1
|
Xu H, Liu M, Li C, Tang Y, Xue Q, Xiao W, Gao D, Peng D, Dai X. Optimizing Agronomic Management Practices for Enhanced Radiation Capture and Improved Radiation Use Efficiency in Winter Wheat. PLANTS (BASEL, SWITZERLAND) 2024; 13:2036. [PMID: 39124154 PMCID: PMC11314148 DOI: 10.3390/plants13152036] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/09/2024] [Revised: 07/16/2024] [Accepted: 07/23/2024] [Indexed: 08/12/2024]
Abstract
Increased aboveground biomass is contingent on enhanced photosynthetically active radiation intercepted by the canopy (IPAR), improved radiation use efficiency (RUE), or both. We investigated whether and how optimized agronomic management practices promote IPAR and RUE. Four integrated agronomic management treatments, i.e., local traditional practice (LP), improved local traditional practice (ILP), high-yield agronomic management (HY), and improved high-yield agronomic management (IHY), were compared over two wheat (Triticum aestivum L.) growing seasons. The average grain yield obtained with IHY was 96% relative to that of HY and was 7% and 23% higher than that with ILP and LP, respectively. Both HY and IHY consistently supported large values of the leaf area index and IPAR fraction, thereby increasing total IPAR. Treatment HY showed increased pre-anthesis RUE, manifested as a higher specific leaf nitrogen content and whole-plant N nutrition index at anthesis. The highest pre-anthesis aboveground biomass was obtained with HY due to the highest pre-anthesis IPAR and RUE. Along with a higher canopy apparent photosynthetic rate, IHY produced higher post-anthesis aboveground biomass due to its higher post-anthesis IPAR and RUE. Treatment IHY had a slightly lower total IPAR but a similar total RUE and harvest index, thus producing a slightly lower grain yield relative to HY. These results demonstrate that the optimized agronomic management practice used under IHY effectively enhances radiation capture and improves radiation utilization. Additionally, the net profit for IHY was higher than that for HY, ILP, and LP by 8%, 11%, and 88%, respectively. Considering the high grain yield, high RUE and high economic benefits, we recommend IHY as the agronomic management practice in the target region, although further study of improvements in pre-anthesis RUE is required.
Collapse
Affiliation(s)
- Haicheng Xu
- Shandong Provincial University Laboratory for Protected Horticulture, Weifang University of Science and Technology, Weifang 262700, China; (H.X.); (M.L.); (Y.T.); (Q.X.); (W.X.); (D.G.)
| | - Mei Liu
- Shandong Provincial University Laboratory for Protected Horticulture, Weifang University of Science and Technology, Weifang 262700, China; (H.X.); (M.L.); (Y.T.); (Q.X.); (W.X.); (D.G.)
| | - Chuanxing Li
- Shouguang Vegetable Industry Development Center, Weifang 262700, China;
| | - Yuhai Tang
- Shandong Provincial University Laboratory for Protected Horticulture, Weifang University of Science and Technology, Weifang 262700, China; (H.X.); (M.L.); (Y.T.); (Q.X.); (W.X.); (D.G.)
| | - Qiqin Xue
- Shandong Provincial University Laboratory for Protected Horticulture, Weifang University of Science and Technology, Weifang 262700, China; (H.X.); (M.L.); (Y.T.); (Q.X.); (W.X.); (D.G.)
| | - Wanli Xiao
- Shandong Provincial University Laboratory for Protected Horticulture, Weifang University of Science and Technology, Weifang 262700, China; (H.X.); (M.L.); (Y.T.); (Q.X.); (W.X.); (D.G.)
| | - Dongyao Gao
- Shandong Provincial University Laboratory for Protected Horticulture, Weifang University of Science and Technology, Weifang 262700, China; (H.X.); (M.L.); (Y.T.); (Q.X.); (W.X.); (D.G.)
| | - Dianliang Peng
- Shandong Provincial University Laboratory for Protected Horticulture, Weifang University of Science and Technology, Weifang 262700, China; (H.X.); (M.L.); (Y.T.); (Q.X.); (W.X.); (D.G.)
| | - Xinglong Dai
- State Key Laboratory of Crop Biology, Agronomy College, Shandong Agricultural University, Tai’an 271018, China
| |
Collapse
|
2
|
Lopes ADR, Lage Filho NM, do Rêgo AC, Domingues FN, da Silva TC, Faturi C, da Silva NC, da Silva WL. Effect of nitrogen fertilization and shading on morphogenesis, structure and leaf anatomy of Megathyrsus maximus genotypes. FRONTIERS IN PLANT SCIENCE 2024; 15:1411952. [PMID: 39104848 PMCID: PMC11298344 DOI: 10.3389/fpls.2024.1411952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 07/11/2024] [Indexed: 08/07/2024]
Abstract
The use of exotic grasses of African origin for pastures in Brazil has been a major advancement in livestock production, but little is known about the responses of these grasses to nitrogen fertilizers associated with shading. In this study, the morphogenetic, structural, and leaf anatomical characteristics of Megathyrsus maximus cultivars' Tamani and Quênia were investigated as a function of N dose and shade. Morphogenetic and structural characteristics and leaf anatomy were studied under three shading levels (0, 30, and 50 %) and four N doses (0, 100, 200, and 300 kg N ha-1) to simulate growth in a silvopastoral system. When comparing the cultivars, Quênia was more efficient in terms of phyllochron up to fertilization with 100 kg N ha-1. The leaf senescence rate of Tamani was higher than that of Quênia at the 30 and 50 % shade levels. The total area (TA) occupied by leaf tissues decreased in Quênia as a function of the increase in N fertilization, whereas the TA of Tamani did not change. The thickness of the adaxial epidermis was greater in Quênia (0.68 µm) than in Tamani (0.50 µm) when not fertilized. The area occupied by the mesophyll was greater in both cultivars when they received fertilization equivalent to 300 kg N ha-1. Quênia grass has a smaller phyllochron than Tamani grass, due to the rapid reconstruction of its photosynthetic apparatus, especially when it receives higher levels of nitrogen fertilization. However, Tamani grass has a greater distribution of plant tissues. The mesophyll area is larger in Tamani grass due to the greater presence of chloroplasts, which facilitates digestion by animals. The Tamani modified the leaf anatomical tissues more significantly in relation to shading, whereas the Quênia modified them in relation to N fertilization, which reinforces the suggestion of a more appropriate use of Tamani in silvopastoral systems.
Collapse
Affiliation(s)
- Aline da Rosa Lopes
- Institute of Veterinary Medicine, Federal University of Pará, Castanhal, Pará, Brazil
| | - Nauara Moura Lage Filho
- Institute of Veterinary Medicine, Federal University of Pará, Castanhal, Pará, Brazil
- Department of Animal Science, Federal University of Ceará, Fortaleza, Ceará, Brazil
| | | | - Felipe Nogueira Domingues
- Institute of Agrarian Science, Federal University of Jequitinhonha and Mucuri Valleys, Unaí, Minas Gerais, Brazil
| | - Thiago Carvalho da Silva
- Institute of Health and Animal Production, Federal Rural University of Amazon, Belém, Pará, Brazil
| | - Cristian Faturi
- Institute of Health and Animal Production, Federal Rural University of Amazon, Belém, Pará, Brazil
| | | | | |
Collapse
|
3
|
Huang R, Wang Z, Wen W, Yao M, Liu H, Li F, Zhang S, Ni D, Chen L. Comprehensive dissection of variation and accumulation of free amino acids in tea accessions. HORTICULTURE RESEARCH 2024; 11:uhad263. [PMID: 38304331 PMCID: PMC10833077 DOI: 10.1093/hr/uhad263] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/11/2023] [Accepted: 11/26/2023] [Indexed: 02/03/2024]
Abstract
Free amino acids (FAAs) positively determine the tea quality, notably theanine (Thea), endowing umami taste of tea infusion, which is the profoundly prevalent research in albino tea genetic resources. Therefore, 339 tea accessions were collected to study FAAs level for deciphering its variation and accumulation mechanism. Interestingly, alanine (Ala) and Thea which had the highest diversity index (H') value among three varieties of Camellia sinensis (L.) O. Kuntze were significantly higher than wild relatives (P < 0.05). The intraspecific arginine (Arg) and glutamine (Gln) contents in C. sinensis var. assamica were significantly lower than sinensis and pubilimba varieties. Moreover, the importance of interdependencies operating across FAAs and chlorophyll levels were highlighted via the cell ultrastructure, metabolomics, and transcriptome analysis. We then determined that the association between phytochrome interacting factor 1 (CsPIF1) identified by weighted gene co-expression network analysis (WGCNA) and Thea content. Intriguingly, transient knock-down CsPIF1 expression increased Thea content in tea plant, and the function verification of CsPIF1 in Arabidopsis also indicated that CsPIF1 acts as a negative regulator of Thea content by mainly effecting the genes expression related to Thea biosynthesis, transport, and hydrolysis, especially glutamate synthase (CsGOGAT), which was validated to be associated with Thea content with a nonsynonymous SNP by Kompetitive Allele-Specific PCR (KASP). We also investigated the interspecific and geographical distribution of this SNP. Taken together, these results help us to understand and clarify the variation and profile of major FAAs in tea germplasms and promote efficient utilization in tea genetic improvement and breeding.
Collapse
Affiliation(s)
- Rong Huang
- Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs; Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Zhihua Wang
- Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs; Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
| | - Weiwei Wen
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Mingzhe Yao
- Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs; Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
| | - Haoran Liu
- Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs; Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
| | - Fang Li
- Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs; Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
| | - Shuran Zhang
- Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs; Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
| | - Dejiang Ni
- College of Horticulture and Forestry Science, Huazhong Agricultural University, Wuhan 430070, China
| | - Liang Chen
- Key Laboratory of Biology, Genetics and Breeding of Special Economic Animals and Plants, Ministry of Agriculture and Rural Affairs; Tea Research Institute of the Chinese Academy of Agricultural Sciences, Hangzhou 310008, China
| |
Collapse
|
4
|
Gauthier M, Barillot R, Schneider A, Chambon C, Fournier C, Pradal C, Robert C, Andrieu B. A functional structural model of grass development based on metabolic regulation and coordination rules. JOURNAL OF EXPERIMENTAL BOTANY 2020; 71:5454-5468. [PMID: 32497176 DOI: 10.1093/jxb/eraa276] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Accepted: 05/27/2020] [Indexed: 05/28/2023]
Abstract
Shoot architecture is a key component of the interactions between plants and their environment. We present a novel model of grass, which fully integrates shoot morphogenesis and the metabolism of carbon (C) and nitrogen (N) at organ scale, within a three-dimensional representation of plant architecture. Plant morphogenesis is seen as a self-regulated system driven by two main mechanisms. First, the rate of organ extension and the establishment of architectural traits are regulated by concentrations of C and N metabolites in the growth zones and the temperature. Second, the timing of extension is regulated by rules coordinating successive phytomers instead of a thermal time schedule. Local concentrations are calculated from a model of C and N metabolism at organ scale. The three-dimensional representation allows the accurate calculation of light and temperature distribution within the architecture. The model was calibrated for wheat (Triticum aestivum) and evaluated for early vegetative stages. This approach allowed the simulation of realistic patterns of leaf dimensions, extension dynamics, and organ mass and composition. The model simulated, as emergent properties, plant and agronomic traits. Metabolic activities of growing leaves were investigated in relation to whole-plant functioning and environmental conditions. The current model is an important step towards a better understanding of the plasticity of plant phenotype in different environments.
Collapse
Affiliation(s)
- Marion Gauthier
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, Thiverval-Grignon, France
- ITK, Clapiers, France
| | | | - Anne Schneider
- Université d'Angers, INRAE, Agrocampus-Ouest, Angers, France
| | - Camille Chambon
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, Thiverval-Grignon, France
| | - Christian Fournier
- Université de Montpellier, INRAE, Montpellier SupAgro, UMR LEPSE, Montpellier, France
| | - Christophe Pradal
- CIRAD, UMR AGAP, and Inria, Montpellier, France
- AGAP, Univ Montpellier, CIRAD, INRAE, Montpellier SupAgro, Montpellier, France
| | - Corinne Robert
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, Thiverval-Grignon, France
| | - Bruno Andrieu
- Université Paris-Saclay, INRAE, AgroParisTech, UMR ECOSYS, Thiverval-Grignon, France
| |
Collapse
|
5
|
Zhang K, Tang J, Wang Y, Kang H, Zeng J. The tolerance to saline-alkaline stress was dependent on the roots in wheat. PHYSIOLOGY AND MOLECULAR BIOLOGY OF PLANTS : AN INTERNATIONAL JOURNAL OF FUNCTIONAL PLANT BIOLOGY 2020; 26:947-954. [PMID: 32377044 PMCID: PMC7196563 DOI: 10.1007/s12298-020-00799-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Revised: 02/03/2020] [Accepted: 03/10/2020] [Indexed: 05/31/2023]
Abstract
Saline-alkaline stress is one of the most serious global problems affecting agriculture, causing enormous economic and yield losses in agricultural production. Wheat, one of the most important crops worldwide, is often subjected to saline-alkaline stress. In this study, two wheat cultivars with different saline-alkaline tolerance, XC-12 (non-tolerance) and XC-45 (tolerance), were used to investigate the influence of saline-alkaline stress on photosynthesis and nitrogen (N) metabolism through hydroponic experiment with aim of elucidating the mechanism of resistance to salt-alkali. These results showed that saline-alkaline stress significantly reduced biomass accumulation, chlorophyll content, photosynthetic ability and N absorption but increased N utilization efficiency. There was no significant difference in photosynthesis between XC-12 and XC-45 under saline-alkaline stress. In addition, XC-45 had lower ratio of Na+/K+ in leaves and Na+-K+ selection rate and higher N absorption ability than XC-12, thereby improving physiological metabolism. Moreover, the roots exhibited greater growth performance in response to saline-alkaline stress as a result of increasing glutamine synthetase activity in roots, thus promoting N metabolism in roots. By coordinating the synergistic effect of increasing soluble protein in root, XC-45 exhibited greater tolerance to saline-alkaline stress. All data pinpoint that the root physiological function was more responsible for resistance to saline-alkaline stress in wheat.
Collapse
Affiliation(s)
- Kehao Zhang
- College of Resource Science and Technology, Sichuan Agricultural University, Chengdu, 611130 China
| | - Jingru Tang
- College of Resource Science and Technology, Sichuan Agricultural University, Chengdu, 611130 China
| | - Yi Wang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, 611130 China
| | - Houyang Kang
- Triticeae Research Institute, Sichuan Agricultural University, Chengdu, 611130 China
| | - Jian Zeng
- College of Resource Science and Technology, Sichuan Agricultural University, Chengdu, 611130 China
| |
Collapse
|
6
|
Yang F, Schäufele R, Liu HT, Ostler U, Schnyder H, Gong XY. Gross and net nitrogen export from leaves of a vegetative C 4 grass. JOURNAL OF PLANT PHYSIOLOGY 2020; 244:153093. [PMID: 31841951 DOI: 10.1016/j.jplph.2019.153093] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Revised: 08/31/2019] [Accepted: 11/29/2019] [Indexed: 06/10/2023]
Abstract
Nitrogen (N) mobilization from mature leaves plays a key role in supplying amino acids to vegetative and reproductive sinks. However, it is unknown if the mobilized N is predominantly sourced by net N-export (a senescence-related process) or other source of N-export from leaves. We used a new approach to partition gross and net N-export from leaf blades at different developmental stages in Cleistogenes squarrosa (a perennial C4 grass). Net N-export was determined as net loss of leaf N with age, while gross N-export was quantified from isotopic mass balances obtained following 24 h-long 15N-labeling with nitrate on 10-12 developmentally distinct (mature and senescing) leaves of individual major tillers. Net N-export was apparent only in older leaves (leaf no. > 7, with leaves numbered basipetally from the tip of the tiller and leaf no. 2 the youngest fully-expanded leaf), while gross N-export was largely independent of leaf age category and was ∼8.4 times greater than the net N-export of a tiller. At whole-tiller level, N import compensated 88 ± 14 (SE) % of gross N-export of all mature blades leading to a net N-export of 0.51 ± 0.07 (SE) μg h-1 tiller-1. N-import was equivalent to 0.09 ± 0.01 (SE) d-1 of total leaf N, similar to reported rates of leaf protein turnover. Gross N-export from all mature blades of a tiller was ∼1.9-times the total demand of the immature tissues of the same (vegetative) tiller. Significant N-export is evident in all mature blades, and is not limited to senescence conditions, implying a much shorter mean residence time of leaf N than that calculated from net N-export. Gross N-export contributes not only to the N demand of the immature tissues of the same tiller but also to N supply of other sinks, such as newly formed tillers. N dynamics at tiller level is integrated with that of the remainder of the shoot, thus highlights the importance of integration of leaf-, tiller-, and plant-scale N dynamics.
Collapse
Affiliation(s)
- Fang Yang
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Rudi Schäufele
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Hai Tao Liu
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Ulrike Ostler
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Hans Schnyder
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany
| | - Xiao Ying Gong
- Technische Universität München, Lehrstuhl für Grünlandlehre, Alte Akademie 12, D-85354, Freising, Germany.
| |
Collapse
|
7
|
Meuriot F, Morvan-Bertrand A, Noiraud-Romy N, Decau ML, Escobar-Gutiérrez AJ, Gastal F, Prud’homme MP. Short-term effects of defoliation intensity on sugar remobilization and N fluxes in ryegrass. JOURNAL OF EXPERIMENTAL BOTANY 2018; 69:3975-3986. [PMID: 29931373 PMCID: PMC6054246 DOI: 10.1093/jxb/ery211] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/12/2018] [Accepted: 06/15/2018] [Indexed: 05/14/2023]
Abstract
In grassland plant communities, the ability of individual plants to regrow after defoliation is of crucial importance since it allows the restoration of active photosynthesis and plant growth. The aim of this study was to evaluate the effects of increasing defoliation intensity (0, 25, 65, 84, and 100% of removed leaf area) on sugar remobilization and N uptake, remobilization, and allocation in roots, adult leaves, and growing leaves of ryegrass over 2 days, using a 15N tracer technique. Increasing defoliation intensity decreased plant N uptake in a correlative way and increased plant N remobilization, but independently. The relative contribution of N stored before defoliation to leaf growth increased when defoliation intensity was severe. In most conditions, root N reserves also contributed to leaf regrowth, but much less than adult leaves and irrespective of defoliation intensity. A threshold of defoliation intensity (65% leaf area removal) was identified below which C (glucose, fructose, sucrose, fructans), and N (amino acids, soluble proteins) storage compounds were not recruited for regrowth. By contrast, nitrate content increased in elongating leaf bases above this threshold. Wounding associated with defoliation is thus not the predominant signal that triggers storage remobilization and controls the priority of resource allocation to leaf meristems. A framework integrating the sequential events leading to the refoliation of grasses is proposed on the basis of current knowledge and on the findings of the present work.
Collapse
Affiliation(s)
- Frédéric Meuriot
- Université de Caen Normandie, INRA, UMR 950, Ecophysiologie Végétale, Agronomie et Nutritions NCS, Caen, France
| | - Annette Morvan-Bertrand
- Université de Caen Normandie, INRA, UMR 950, Ecophysiologie Végétale, Agronomie et Nutritions NCS, Caen, France
| | - Nathalie Noiraud-Romy
- Université de Caen Normandie, INRA, UMR 950, Ecophysiologie Végétale, Agronomie et Nutritions NCS, Caen, France
| | - Marie-Laure Decau
- Université de Caen Normandie, INRA, UMR 950, Ecophysiologie Végétale, Agronomie et Nutritions NCS, Caen, France
| | | | | | - Marie-Pascale Prud’homme
- Université de Caen Normandie, INRA, UMR 950, Ecophysiologie Végétale, Agronomie et Nutritions NCS, Caen, France
| |
Collapse
|
8
|
Muñoz-Nortes T, Pérez-Pérez JM, Sarmiento-Mañús R, Candela H, Micol JL. Deficient glutamate biosynthesis triggers a concerted upregulation of ribosomal protein genes in Arabidopsis. Sci Rep 2017; 7:6164. [PMID: 28733652 PMCID: PMC5522406 DOI: 10.1038/s41598-017-06335-4] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 06/29/2017] [Indexed: 11/29/2022] Open
Abstract
Biomass production requires the coordination between growth and metabolism. In a large-scale screen for mutants affected in leaf morphology, we isolated the orbiculata1 (orb1) mutants, which exhibit a pale green phenotype and reduced growth. The combination of map-based cloning and next-generation sequencing allowed us to establish that ORB1 encodes the GLUTAMATE SYNTHASE 1 (GLU1) enzyme, also known as FERREDOXIN-DEPENDENT GLUTAMINE OXOGLUTARATE AMINOTRANSFERASE 1 (Fd-GOGAT1). We performed an RNA-seq analysis to identify global gene expression changes in the orb1–3 mutant. We found altered expression levels of genes encoding enzymes involved in nitrogen assimilation and amino acid biosynthesis, such as glutamine synthetases, asparagine synthetases and glutamate dehydrogenases, showing that the expression of these genes depends on the levels of glutamine and/or glutamate. In addition, we observed a concerted upregulation of genes encoding subunits of the cytosolic ribosome. A gene ontology (GO) analysis of the differentially expressed genes between Ler and orb1–3 showed that the most enriched GO terms were ‘translation’, ‘cytosolic ribosome’ and ‘structural constituent of ribosome’. The upregulation of ribosome-related functions might reflect an attempt to keep protein synthesis at optimal levels even when the pool of glutamate is reduced.
Collapse
Affiliation(s)
- Tamara Muñoz-Nortes
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - José Manuel Pérez-Pérez
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - Raquel Sarmiento-Mañús
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - Héctor Candela
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain
| | - José Luis Micol
- Instituto de Bioingeniería, Universidad Miguel Hernández, Campus de Elche, 03202, Elche, Spain.
| |
Collapse
|
9
|
Fuchs B, Breuer T, Findling S, Krischke M, Mueller MJ, Holzschuh A, Krauss J. Enhanced aphid abundance in spring desynchronizes predator-prey and plant-microorganism interactions. Oecologia 2017; 183:469-478. [PMID: 27858148 PMCID: PMC5306164 DOI: 10.1007/s00442-016-3768-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Accepted: 11/04/2016] [Indexed: 11/10/2022]
Abstract
Climate change leads to phenology shifts of many species. However, not all species shift in parallel, which can desynchronize interspecific interactions. Within trophic cascades, herbivores can be top-down controlled by predators or bottom-up controlled by host plant quality and host symbionts, such as plant-associated micro-organisms. Synchronization of trophic levels is required to prevent insect herbivore (pest) outbreaks. In a common garden experiment, we simulated an earlier arrival time (~2 weeks) of the aphid Rhopalosiphum padi on its host grass Lolium perenne by enhancing the aphid abundance during the colonization period. L. perenne was either uninfected or infected with the endophytic fungus Epichloë festucae var. lolii. The plant symbiotic fungus produces insect deterring alkaloids within the host grass. Throughout the season, we tested the effects of enhanced aphid abundance in spring on aphid predators (top-down) and grass-endophyte (bottom-up) responses. Higher aphid population sizes earlier in the season lead to overall higher aphid abundances, as predator occurrence was independent of aphid abundances on the pots. Nonetheless, after predator occurrence, aphids were controlled within 2 weeks on all pots. Possible bottom-up control of aphids by increased endophyte concentrations occurred time delayed after high herbivore abundances. Endophyte-derived alkaloid concentrations were not significantly affected by enhanced aphid abundance but increased throughout the season. We conclude that phenology shifts in an herbivorous species can desynchronize predator-prey and plant-microorganism interactions and might enhance the probability of pest outbreaks with climate change.
Collapse
Affiliation(s)
- Benjamin Fuchs
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany.
| | - Tatjana Breuer
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Simone Findling
- Department of Pharmaceutical Biology, Biocenter, University of Würzburg, Julius von Sachs Platz 2, 97082, Würzburg, Germany
| | - Markus Krischke
- Department of Pharmaceutical Biology, Biocenter, University of Würzburg, Julius von Sachs Platz 2, 97082, Würzburg, Germany
| | - Martin J Mueller
- Department of Pharmaceutical Biology, Biocenter, University of Würzburg, Julius von Sachs Platz 2, 97082, Würzburg, Germany
| | - Andrea Holzschuh
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| | - Jochen Krauss
- Department of Animal Ecology and Tropical Biology, Biocenter, University of Würzburg, Am Hubland, 97074, Würzburg, Germany
| |
Collapse
|
10
|
Yang F, Gong XY, Liu HT, Schäufele R, Schnyder H. Effects of nitrogen and vapour pressure deficit on phytomer growth and development in a C4 grass. AOB PLANTS 2017; 8:plw075. [PMID: 27810947 PMCID: PMC5206350 DOI: 10.1093/aobpla/plw075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 10/19/2016] [Indexed: 05/12/2023]
Abstract
Phytomers are basic morphological units of plants. Knowledge of phytomer development is essential for understanding morphological plasticity, functional-structural modelling of plant growth and the usage of leaf characteristics to indicate growth conditions at the time of production (e.g. stable isotope signals). Yet, systematic analysis on the process of phytomer development is unavailable for wild or perennial C4 grasses. Also, effects of environmental factors, such as nitrogen nutrition or vapour pressure deficit (VPD), on coordination events of developmental processes of C4 grasses have not been studied. This study investigates phytomer growth and development in Cleistogenes squarrosa, a predominant C4 grass in the Eurasian steppe, grown at low (0.63 kPa) or high (1.58 kPa) VPD with low or high nitrogen supply in controlled environments. Elongation of phytomers on marked tillers was measured daily for 13 days. Then lengths of immature and mature phytomer components (blade, sheath and internode) of all phytomers were measured following dissection. Nitrogen nutrition and VPD had no effects on coordination of growth within and between phytomers: phytomer tips emerged when phytomers reached 26 % of their final length, coincident with the acceleration phase of its elongation; blade elongation stopped when phytomers reached ∼75 % of their final length and elongation of the preceding phytomer was confined to the internode. The relationship between fraction of final phytomer length and days after tip emergence for all treatments was well described by a sigmoidal function: y = 1/{1 + exp[(1.82 - x)/1.81]}. C. squarrosa exhibited little morphological plasticity at phytomer-level in response to nitrogen supply and VPD, but a clear increase in tillering under high N supply. Also, the invariant coordination of elongation within and between phytomers was a stable developmental feature, thus the quantitative coordination rules are applicable for predicting morphological development of C. squarrosa under contrasting levels of nitrogen nutrition or VPD.
Collapse
Affiliation(s)
- Fang Yang
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Xiao Ying Gong
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Hai Tao Liu
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Rudi Schäufele
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| | - Hans Schnyder
- Lehrstuhl für Grünlandlehre, Department für Pflanzenwissenschaften, Technische Universität München, Alte Akademie 12, D-85354 Freising, Germany
| |
Collapse
|
11
|
Sprangers K, Avramova V, Beemster GTS. Kinematic Analysis of Cell Division and Expansion: Quantifying the Cellular Basis of Growth and Sampling Developmental Zones in Zea mays Leaves. J Vis Exp 2016:54887. [PMID: 28060300 PMCID: PMC5226352 DOI: 10.3791/54887] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Growth analyses are often used in plant science to investigate contrasting genotypes and the effect of environmental conditions. The cellular aspect of these analyses is of crucial importance, because growth is driven by cell division and cell elongation. Kinematic analysis represents a methodology to quantify these two processes. Moreover, this technique is easy to use in non-specialized laboratories. Here, we present a protocol for performing a kinematic analysis in monocotyledonous maize (Zea mays) leaves. Two aspects are presented: (1) the quantification of cell division and expansion parameters, and (2) the determination of the location of the developmental zones. This could serve as a basis for sampling design and/or could be useful for data interpretation of biochemical and molecular measurements with high spatial resolution in the leaf growth zone. The growth zone of maize leaves is harvested during steady-state growth. Individual leaves are used for meristem length determination using a DAPI stain and cell-length profiles using DIC microscopy. The protocol is suited for emerged monocotyledonous leaves harvested during steady-state growth, with growth zones spanning at least several centimeters. To improve the understanding of plant growth regulation, data on growth and molecular studies must be combined. Therefore, an important advantage of kinematic analysis is the possibility to correlate changes at the molecular level to well-defined stages of cellular development. Furthermore, it allows for a more focused sampling of specified developmental stages, which is useful in case of limited budget or time.
Collapse
|
12
|
Céccoli G, Bustos D, Ortega LI, Senn ME, Vegetti A, Taleisnik E. Plasticity in sunflower leaf and cell growth under high salinity. PLANT BIOLOGY (STUTTGART, GERMANY) 2015; 17:41-51. [PMID: 24942979 DOI: 10.1111/plb.12205] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2014] [Accepted: 04/09/2014] [Indexed: 05/21/2023]
Abstract
A group of sunflower lines that exhibit a range of leaf Na(+) concentrations under high salinity was used to explore whether the responses to the osmotic and ionic components of salinity can be distinguished in leaf expansion kinetics analysis. It was expected that at the initial stages of the salt treatment, leaf expansion kinetics changes would be dominated by responses to the osmotic component of salinity, and that later on, ion inclusion would impose further kinetics changes. It was also expected that differential leaf Na(+) accumulation would be reflected in specific changes in cell division and expansion rates. Plants of four sunflower lines were gradually treated with a relatively high (130 mm NaCl) salt treatment. Leaf expansion kinetics curves were compared in leaves that were formed before, during and after the initiation of the salt treatment. Leaf areas were smaller in salt-treated plants, but the analysis of growth curves did not reveal differences that could be attributed to differential Na(+) accumulation, since similar changes in leaf expansion kinetics were observed in lines with different magnitudes of salt accumulation. Nevertheless, in a high leaf Na(+) -including line, cell divisions were affected earlier, resulting in leaves with proportionally fewer cells than in a Na(+) -excluding line. A distinct change in leaf epidermal pavement shape caused by salinity is reported for the first time. Mature pavement cells in leaves of control plants exhibited typical lobed, jigsaw-puzzle shape, whereas in treated plants, they tended to retain closer-to-circular shapes and a lower number of lobes.
Collapse
Affiliation(s)
- G Céccoli
- Facultad de Ciencias Agrarias, Instituto de Agrobiotecnología del Litoral (CONICET-Universidad Nacional del Litoral), Esperanza, Argentina; CONICET, Consejo de Investigaciones Científicas y Técnicas de la República Argentina, Córdoba, Argentina
| | | | | | | | | | | |
Collapse
|
13
|
Lehmeier CA, Wild M, Schnyder H. Nitrogen stress affects the turnover and size of nitrogen pools supplying leaf growth in a grass. PLANT PHYSIOLOGY 2013; 162:2095-105. [PMID: 23757403 PMCID: PMC3729785 DOI: 10.1104/pp.113.219311] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2013] [Accepted: 06/10/2013] [Indexed: 05/18/2023]
Abstract
The effect of nitrogen (N) stress on the pool system supplying currently assimilated and (re)mobilized N for leaf growth of a grass was explored by dynamic ¹⁵N labeling, assessment of total and labeled N import into leaf growth zones, and compartmental analysis of the label import data. Perennial ryegrass (Lolium perenne) plants, grown with low or high levels of N fertilization, were labeled with ¹⁵NO₃⁻/¹⁴NO₃⁻ from 2 h to more than 20 d. In both treatments, the tracer time course in N imported into the growth zones fitted a two-pool model (r² > 0.99). This consisted of a "substrate pool," which received N from current uptake and supplied the growth zone, and a recycling/mobilizing "store," which exchanged with the substrate pool. N deficiency halved the leaf elongation rate, decreased N import into the growth zone, lengthened the delay between tracer uptake and its arrival in the growth zone (2.2 h versus 0.9 h), slowed the turnover of the substrate pool (half-life of 3.2 h versus 0.6 h), and increased its size (12.4 μg versus 5.9 μg). The store contained the equivalent of approximately 10 times (low N) and approximately five times (high N) the total daily N import into the growth zone. Its turnover agreed with that of protein turnover. Remarkably, the relative contribution of mobilization to leaf growth was large and similar (approximately 45%) in both treatments. We conclude that turnover and size of the substrate pool are related to the sink strength of the growth zone, whereas the contribution of the store is influenced by partitioning between sinks.
Collapse
|
14
|
Zegada-Lizarazu W, Wullschleger SD, Surendran Nair S, Monti A. Crop Physiology. GREEN ENERGY AND TECHNOLOGY 2012. [DOI: 10.1007/978-1-4471-2903-5_3] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
15
|
Granier C, Tardieu F. Multi-scale phenotyping of leaf expansion in response to environmental changes: the whole is more than the sum of parts. PLANT, CELL & ENVIRONMENT 2009; 32:1175-84. [PMID: 19210637 DOI: 10.1111/j.1365-3040.2009.01955.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The leaf is a multi-scale dynamic unit that is determined by mechanisms at different organizational scales (cell, tissue, whole leaf and whole plant) and affected by both internal (genotype) and external (environmental) determinisms. The recent development of phenotyping platforms and imaging techniques provides new insights into the temporal and spatial patterns of leaf growth as affected by those determinisms. Conclusions about the overriding mechanisms often depend on the considered organizational scale and of time resolution which varies from minutes to several weeks. Analyses of leaf growth responses to environmental conditions have revealed robust emerging properties at whole plant or whole leaf scales. They have highlighted that the control of individual leaf expansion is more complex than merely the sum of cellular processes, and the control at the whole plant level is more complex than the sum of individual leaf expansions. However, in many cases, the integrated leaf-growth variable can be simplified to a limited set of underlying variables to be measured for comparative analyses of leaf growth or modelling purposes.
Collapse
Affiliation(s)
- Christine Granier
- Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux UMR 759, Institut de Biologie Intégrative des Plantes, Institut National de la Recherche Agronomique/Ecole Nationale Supérieure d'Agronomie, Place Viala, F-34060 Montpellier, Cedex 1, France
| | | |
Collapse
|
16
|
Kavanová M, Lattanzi FA, Schnyder H. Nitrogen deficiency inhibits leaf blade growth in Lolium perenne by increasing cell cycle duration and decreasing mitotic and post-mitotic growth rates. PLANT, CELL & ENVIRONMENT 2008; 31:727-37. [PMID: 18208511 DOI: 10.1111/j.1365-3040.2008.01787.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
Nitrogen deficiency severely inhibits leaf growth. This response was analysed at the cellular level by growing Lolium perenne L. under 7.5 mM (high) or 1 mM (low) nitrate supply, and performing a kinematic analysis to assess the effect of nitrogen status on cell proliferation and cell growth in the leaf blade epidermis. Low nitrogen supply reduced leaf elongation rate (LER) by 43% through a similar decrease in the cell production rate and final cell length. The former was entirely because of a decreased average cell division rate (0.023 versus 0.032 h(-1)) and thus longer cell cycle duration (30 versus 22 h). Nitrogen status did not affect the number of division cycles of the initial cell's progeny (5.7), and accordingly the meristematic cell number (53). Meristematic cell length was unaffected by nitrogen deficiency, implying that the division and mitotic growth rates were equally impaired. The shorter mature cell length arose from a considerably reduced post-mitotic growth rate (0.033 versus 0.049 h(-1)). But, nitrogen stress did not affect the position where elongation stopped, and increased cell elongation duration. In conclusion, nitrogen deficiency limited leaf growth by increasing the cell cycle duration and decreasing mitotic and post-mitotic elongation rates, delaying cell maturation.
Collapse
Affiliation(s)
- Monika Kavanová
- Lehrstuhl für Grünlandlehre, Technische Universität München, Am Hochanger 1, D-85350 Freising, Weihenstephan, Germany
| | | | | |
Collapse
|
17
|
Hu Y, Schmidhalter U. Spatial and temporal quantitative analysis of cell division and elongation rate in growing wheat leaves under saline conditions. JOURNAL OF INTEGRATIVE PLANT BIOLOGY 2008; 50:76-83. [PMID: 18666954 DOI: 10.1111/j.1744-7909.2007.00379.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Leaf growth in grasses is determined by the cell division and elongation rates, with the duration of cell elongation being one of the processes that is the most sensitive to salinity. Our objective was to investigate the distribution profiles of cell production, cell length and the duration of cell elongation in the growing zone of the wheat leaf during the steady growth phase. Plants were grown in loamy soil with or without 120 mmol/L NaCl in a growth chamber, and harvested at day 3 after leaf 4 emerged. Results show that the elongation rate of leaf 4 was reduced by 120 mmol/L NaCl during the steady growth phase. The distribution profile of the lengths of abaxial epidermal cells of leaf 4 during the steady growth stage shows a sigmoidal pattern along the leaf axis for both treatments. Although salinity did not affect or even increased the length of the epidermal cells in some locations in the growth zone compared to the control treatment, the final length of the epidermal cells was reduced by 14% at 120 mmol/L NaCl. Thus, we concluded that the observed reduction in the leaf elongation rate derived in part from the reduced cell division rate and either the shortened cell elongation zone or shortened duration of cell elongation. This suggests that more attention should be paid to the effects of salinity on those properties of cell production and the period of cell maturation that are related to the properties of cell wall.
Collapse
Affiliation(s)
- Yuncai Hu
- Technical University of Munich, Freising D-85350, Germany.
| | | |
Collapse
|
18
|
Basu P, Pal A, Lynch JP, Brown KM. A novel image-analysis technique for kinematic study of growth and curvature. PLANT PHYSIOLOGY 2007; 145:305-16. [PMID: 17720760 PMCID: PMC2048733 DOI: 10.1104/pp.107.103226] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
Kinematic analysis has provided important insights into the biology of growth by revealing the distribution of expansion within growing organs. Modern methods of kinematic analysis have made use of new image-tracking algorithms and computer-assisted evaluation, but these methods have yet to be adapted for examination of growth in a variety of plant species or for analysis of graviresponse. Therefore, a new image-analysis program, KineRoot, was developed to study spatio-temporal patterns of growth and curvature of roots. Graphite particles sprinkled on the roots create random patterns that can be followed by image analysis. KineRoot tracks the displacement of patterns created by the graphite particles over space and time using three search algorithms. Following pattern tracking, the edges of the roots are identified automatically by an edge detection algorithm that provides root diameter and root midline. Local growth rate of the root is measured by projecting the tracked points on the midline. From the shape of the root midline, root curvature is calculated. By combining curvature measurement with root diameter, the differential growth ratio between the greater and lesser curvature edges of a bending root is calculated. KineRoot is capable of analyzing a large number of images to generate local root growth and root curvature data over several hours, permitting kinematic analysis of growth and gravitropic responses for a variety of root types.
Collapse
Affiliation(s)
- Paramita Basu
- Intercollege Program in Plant Biology, Pennsylvania State University, University Park, Pennsylvania 16802, USA
| | | | | | | |
Collapse
|
19
|
PONTES LDAS, SOUSSANA JF, LOUAULT F, ANDUEZA D, CARRÈRE P. Leaf traits affect the above-ground productivity and quality of pasture grasses. Funct Ecol 2007. [DOI: 10.1111/j.1365-2435.2007.01316.x] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
|
20
|
GRAAL-CN: A model of GRowth, Architecture and ALlocation for Carbon and Nitrogen dynamics within whole plants formalised at the organ level. Ecol Modell 2007. [DOI: 10.1016/j.ecolmodel.2007.03.036] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
|
21
|
Kavanová M, Grimoldi AA, Lattanzi FA, Schnyder H. Phosphorus nutrition and mycorrhiza effects on grass leaf growth. P status- and size-mediated effects on growth zone kinematics. PLANT, CELL & ENVIRONMENT 2006; 29:511-20. [PMID: 17080603 DOI: 10.1111/j.1365-3040.2005.01428.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
This study tested whether leaf elongation rate (LER, mm h(-1)) and its components--average relative elemental growth rate (REGRavg, mm mm(-1) h(-1)) and leaf growth zone length (L(LGZ), mm)--are related to phosphorus (P) concentration in the growth zone (P(LGZ) mg P g(-1) tissue water) of Lolium perenne L. cv. Condesa and whether such relationships are modified by the arbuscular mycorrhizal fungus (AMF) Glomus hoi. Mycorrhizal and non-mycorrhizal plants were grown at a range of P supply rates and analysed at either the same plant age or the same tiller size (defined by the length of the sheath of the youngest fully expanded leaf). Both improved P supply (up to 95%) and AMF (up to 21%) strongly increased LER. In tillers of even-aged plants, this was due to increased REGRavg and L(LGZ). In even-sized tillers, it was exclusively due to increased REGRavg. REGRavg was strictly related to P(LGZ) (r2 = 0.95) and independent of tiller size. Conversely, L(LGZ) strictly depended on tiller size (r2 = 0.88) and not on P(LGZ). Hence, P status affected leaf growth directly only through effects on relative tissue expansion rates. Symbiosis with AMF did not modify these relationships. Thus, no evidence for P status-independent effects of AMF on LER was found.
Collapse
Affiliation(s)
- Monika Kavanová
- Lehrstuhl für Grünlandlehre, Technische Universität München, Am Hochanger 1, D-85350 Freising-Weihenstephan, Germany
| | | | | | | |
Collapse
|
22
|
La H, Li J, Ji Z, Cheng Y, Li X, Jiang S, Venkatesh PN, Ramachandran S. Genome-wide analysis of cyclin family in rice (Oryza Sativa L.). Mol Genet Genomics 2006; 275:374-86. [PMID: 16435118 DOI: 10.1007/s00438-005-0093-5] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2005] [Accepted: 12/17/2005] [Indexed: 11/24/2022]
Abstract
The cyclins together with highly conserved cyclin-dependent kinases regulate cell cycle progression in plants. Although extensive and systematic study on cell cycle mechanisms and cyclin functions in yeasts and animals has been carried out, only a small number of plant cyclins have been characterized and classified functionally and phylogenetically. We identified several types of cyclin genes in the rice genome and characterized them by phylogenetic, tandem and segmental duplications analyses. Our results indicated that there were at least 49 predicted rice cyclin genes in the rice genome, and they were distributed on 12 chromosomes. Of these cyclins, one possessed only cyclin_C domain and no cyclin_N domain, and the remaining 48 cyclins with cyclin_N domains were classified as nine types based on evolutionary relationships. Eight of these nine types were common between rice and Arabidopsis, whereas only one, known as F-type cyclins, was unique to rice. No homologues of the F-type cyclins in plants could be retrieved from the public databases, and reverse transcription-PCR analysis supported an existence of the F-type cyclin genes. Sequence alignment suggested that the cyclin genes in the rice genome experienced a mass of gene tandem and segmental duplications occurred on seven chromosomes related to the origins of new cyclin genes. Our study provided an opportunity to facilitate assessment and classification of new members, serving as a guide for further functional elucidation of rice cyclins.
Collapse
Affiliation(s)
- Honggui La
- Rice Functional Genomics, Joint Laboratory of Temasek Life Sciences Laboratory of Singapore and Institute of Genetics and Developmental Biology, The Chinese Academy of Sciences, 100101, Beijing, China
| | | | | | | | | | | | | | | |
Collapse
|
23
|
Abstract
A simple, improved model of Rubisco synthesis and degradation in cereal leaves is developed using data obtained over the leaf lifespan to return maximum likelihood values for Rubisco proteolysis and biosynthesis. It assumes that the time course of leaf Rubisco content can be described using a log-normal curve, and degradation of the Rubisco pool occurs exponentially. Curve parameters give an insight into how Rubisco dynamics differ among treatments or genotypes; also, statistical analyses can be performed more easily, requiring fewer data and allowing more flexibility in sampling than previous studies. Predicted patterns of synthesis correlate well with independent rbc gene transcript data. Rubisco degradation is a first-order decay process, and biosynthesis correlates with leaf elongation rates. As Rubisco degradation takes place according to first-order kinetics, control of leaf Rubisco concentration must be exerted by adjustment of biosynthetic, rather than proteolytic, rates.
Collapse
Affiliation(s)
- Louis John Irving
- School of Biological Sciences, University of Aberdeen, Cruickshank Building, St Machar Drive, Aberdeen AB24 3UU, UK.
| | | |
Collapse
|
24
|
Hu Y, Fricke W, Schmidhalter U. Salinity and the growth of non-halophytic grass leaves: the role of mineral nutrient distribution. FUNCTIONAL PLANT BIOLOGY : FPB 2005; 32:973-985. [PMID: 32689193 DOI: 10.1071/fp05080] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 07/27/2005] [Indexed: 06/11/2023]
Abstract
Salinity is increasingly limiting the production of graminaceous crops constituting the main sources of staple food (rice, wheat, barley, maize and sorghum), primarily through reductions in the expansion and photosynthetic yield of the leaves. In the present review, we summarise current knowledge of the characteristics of the spatial distribution patterns of the mineral elements along the growing grass leaf and of the impact of salinity on these patterns. Although mineral nutrients have a wide range of functions in plant tissues, their functions may differ between growing and non-growing parts of the grass leaf. To identify the physiological processes by which salinity affects leaf elongation in non-halophytic grasses, patterns of mineral nutrient deposition related to developmental and anatomical gradients along the growing grass leaf are discussed. The hypothesis that a causal link exists between ion deficiency and / or toxicity and the inhibition of leaf growth of grasses in a saline environment is tested.
Collapse
Affiliation(s)
- Yuncai Hu
- Chair of Plant Nutrition, Department of Plant Sciences, Technical University of Munich, D-85350 Freising, Germany
| | - Wieland Fricke
- Division of Biology, University of Paisley, Paisley PA1 2BE, Scotland, UK
| | - Urs Schmidhalter
- Chair of Plant Nutrition, Department of Plant Sciences, Technical University of Munich, D-85350 Freising, Germany
| |
Collapse
|
25
|
Massonneau A, Condamine P, Wisniewski JP, Zivy M, Rogowsky PM. Maize cystatins respond to developmental cues, cold stress and drought. ACTA ACUST UNITED AC 2005; 1729:186-99. [PMID: 15979170 DOI: 10.1016/j.bbaexp.2005.05.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2005] [Revised: 05/02/2005] [Accepted: 05/07/2005] [Indexed: 11/23/2022]
Abstract
Comprehensive searches of maize EST data allowed us to identify 8 novel Corn Cystatin (CC) genes in addition to the previously known genes CCI and CCII. The deduced amino acid sequences of all 10 genes contain the typical cystatin family signature. In addition, they show an extended overall similarity with cystatins from other species that belong to several different phyto-cystatin subfamilies. To gain further insight into their respective roles in the maize plant, gene-specific expression profiles were established by semi-quantitative RT-PCR. While 7 CC genes were expressed in two or more tissues varying from gene to gene, CCI was preferentially expressed in immature tassels and CC8 and CC10 in developing kernels. As shown by in situ hybridisation of maize kernels, CC8 was specifically expressed in the basal region of the endosperm and CC10 both in the starchy endosperm and the scutellum of the embryo. The remaining, not kernel-specific genes, all had distinct expression kinetics during kernel development, generally with peaks during the early stages. In addition to developmental regulation, the effect of cold stress and water starvation were tested on cystatin expression. Two genes (CC8 and CC9) were induced by cold stress and 5 genes (CCII, CC3, CC4, CC5 and CC9) were down-regulated in response to water starvation. Taken together our data suggest distinct functions for CC genes in the maize plant.
Collapse
Affiliation(s)
- Agnès Massonneau
- RDP, UMR 5667 CNRS-INRA-ENSL-UCBL, IFR128 BioSciences Lyon-Gerland, ENS-Lyon, 46 Allée d'Italie, F-69364 Lyon Cedex 07, France
| | | | | | | | | |
Collapse
|
26
|
Girousse C, Moulia B, Silk W, Bonnemain JL. Aphid infestation causes different changes in carbon and nitrogen allocation in alfalfa stems as well as different inhibitions of longitudinal and radial expansion. PLANT PHYSIOLOGY 2005; 137:1474-84. [PMID: 15778456 PMCID: PMC1088336 DOI: 10.1104/pp.104.057430] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2004] [Revised: 02/25/2005] [Accepted: 03/01/2005] [Indexed: 05/19/2023]
Abstract
Alfalfa (Medicago sativa) stem elongation is strongly reduced by a pea aphid (Acyrthosiphon pisum Harris) infestation. As pea aphid is a phloem feeder that does not transmit virus or toxins, assimilate withdrawal is generally considered as the main mechanism responsible for growth reduction. Using a kinematic analysis, we investigated the spatial distributions of relative elemental growth rates of control and infested alfalfa stems. The water, carbon, and nitrogen contents per unit stem length were measured along the growth zone. Deposition rates and growth-sustaining fluxes were estimated from these patterns. Severe short-term aphid infestation (200 young adults over a 24-h period) induced a strong and synchronized reduction in rates of elongation and of water and carbon deposition. Reduced nitrogen content and associated negative nitrogen deposition rates were observed in some parts of the infested stems, especially in the apex. This suggested a mobilization of nitrogen from the apical part of the growth zone, converted from a sink tissue into a source tissue by aphids. Calculation of radial growth rates suggested that aphid infestation led to a smaller reduction in radial expansion than in elongation. Together with earlier observations of long-lasting effects of a short-term infestation, this supports the hypothesis that in addition to nutrient withdrawal, a thigmomorphogenesis-like mechanism is involved in the effect of aphid infestation on stem growth.
Collapse
Affiliation(s)
- Christine Girousse
- Unité de Recherches de Zoologie, Institut National de la Recherche Agronomique, F-86600 Lusignan, France.
| | | | | | | |
Collapse
|
27
|
Lattanzi FA, Schnyder H, Thornton B. The sources of carbon and nitrogen supplying leaf growth. Assessment of the role of stores with compartmental models. PLANT PHYSIOLOGY 2005; 137:383-95. [PMID: 15618429 PMCID: PMC548867 DOI: 10.1104/pp.104.051375] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2004] [Revised: 10/13/2004] [Accepted: 10/26/2004] [Indexed: 05/22/2023]
Abstract
Patterns of synthesis and breakdown of carbon (C) and nitrogen (N) stores are relatively well known. But the role of mobilized stores as substrates for growth remains less clear. In this article, a novel approach to estimate C and N import into leaf growth zones was coupled with steady-state labeling of photosynthesis ((13)CO(2)/(12)CO(2)) and N uptake ((15)NO(3)(-)/(14)NO(3)(-)) and compartmental modeling of tracer fluxes. The contributions of current C assimilation/N uptake and mobilization from stores to the substrate pool supplying leaf growth were then quantified in plants of a C(3) (Lolium perenne) and C(4) grass (Paspalum dilatatum Poir.) manipulated thus to have contrasting C assimilation and N uptake rates. In all cases, leaf growth relied largely on photoassimilates delivered either directly after fixation or short-term storage (turnover rate = 1.6-3.3 d(-1)). Long-term C stores (turnover rate < 0.09 d(-1)) were generally of limited relevance. Hence, no link was found between the role of stores and C acquisition rate. Short-term (turnover rate = 0.29-0.90 d(-1)) and long-term (turnover rate < 0.04 d(-1)) stores supplied most N used in leaf growth. Compared to dominant (well-lit) plants, subordinate (shaded) plants relied more on mobilization from long-term N stores to support leaf growth. These differences correlated well with the C-to-N ratio of growth substrates and were associated with responses in N uptake. Based on this, we argue that internal regulation of N uptake acts as a main determinant of the importance of mobilized long-term stores as a source of N for leaf growth.
Collapse
Affiliation(s)
- Fernando Alfredo Lattanzi
- Lehrstuhl für Grünlandlehre, Technische Universität München, D-85350 Freising-Weihenstephan, Germany
| | | | | |
Collapse
|
28
|
Macduff JH, Bakken AK. Diurnal variation in uptake and xylem contents of inorganic and assimilated N under continuous and interrupted N supply to Phleum pratense and Festuca pratensis. JOURNAL OF EXPERIMENTAL BOTANY 2003; 54:431-444. [PMID: 12493871 DOI: 10.1093/jxb/erg058] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Compensation by dark-period uptake of NH(4)(+) and NO(3)(-) in the grasses Phleum pratense L. and Festuca pratensis Huds. following N deprivation during the preceding light period was investigated in flowing solution culture under an artificial 10/14 h light/dark cycle. N was supplied as either NO(3)(-), NH(4)(+) or NH(4)NO(3) at 20+/-5 mmol m(-3), available continuously or only during the dark period, for 5-10 d. Intermittent N supply did not affect total daily N uptake, growth rate or net partitioning of dry matter. Net uptake and influx of NO(3)(-) varied similarly throughout the diurnal cycle when NO(3)(-) was supplied continuously, with a marginal contribution by NO(3)(-) efflux. Influx was significantly higher and efflux slightly higher following interruption of NO(3)(-) supply during the light period. Nitrate accounted for 80% of N in xylem exudate except between hours 6-9 of the light period when the amino acid concentration increased 3-fold, primarily as glutamine. Diurnal variation in relative NO(3)(-) uptake exhibited five phases of constant acceleration/deceleration, described reasonably well assuming NO(3)(-) influx was subject to metabolic co-regulation by NO(3)(-) and amino acid levels in the cytoplasmic compartment of the roots. Accordingly, influx is determined by variation in root NO(3)(-) levels throughout the dark period and the first half of the light period, but is down-regulated by increased amino acid levels during the second half of the light period. The sharp light/dark transitions affect transpiration rate and hence xylem N flux which, in turn, affect NO(3)(-) levels in the cytoplasmic compartment of the roots and the rate of NO(3)(-) assimilation in the shoot.
Collapse
Affiliation(s)
- J H Macduff
- Institute of Grassland and Environmental Research, Aberystwyth Research Centre, Aberystwyth SY23 3EB, UK.
| | | |
Collapse
|
29
|
Thornton B, Macduff JH. Short-term changes in xylem N compounds in Lolium perenne following defoliation. ANNALS OF BOTANY 2002; 89:715-722. [PMID: 12102527 PMCID: PMC4233839 DOI: 10.1093/aob/mcf132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Previous studies have indicated that an increased asparagine to glutamine ratio (Asn : Gln) occurs in the xylem fluid of Lolium perenne 24 h after defoliation. However, the absolute changes in Asn and Gln leading to the increased Asn : Gln ratio are unknown. The present study tested the hypotheses that: (1) defoliation-induced changes in xylem amino acid composition occur in L perenne within the first 24 h following defoliation, irrespective of phasing with respect to the diurnal light/dark cycle; and (2) the increase in Asn : Gln ratio in the xylem fluid of L perenne following defoliation is due to an increase in Asn content. Plants of L perenne L. 'Aurora' were grown in flowing solution culture for 40 d. Plants were then either left intact, defoliated at the end of the light period or defoliated at the end of the dark period. 15N-labelled NO3- was supplied following defoliation to discriminate between the recovery of N absorbed prior to, and following, defoliation. Xylem samples were collected over the subsequent 24 h period with amino acids speciated by GC-MS. There was support for the first hypothesis: increased Asn : Gln ratios occurred within the first 24 h, irrespective of the phasing of defoliation with respect to light/dark cycles. The second hypothesis was not supported: the concentration of all amino acids in the xylem exudate declined after defoliation, and the increased Asn : Gln ratio was accounted for by a disproportionately large reduction in Gln levels. Low concentrations of amino acids in the xylem of defoliated plants precluded accurate discrimination of their nitrogen content into pre- and post-defoliation sources.
Collapse
Affiliation(s)
- B Thornton
- Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, UK.
| | | |
Collapse
|
30
|
Gastal F, Lemaire G. N uptake and distribution in crops: an agronomical and ecophysiological perspective. JOURNAL OF EXPERIMENTAL BOTANY 2002; 53:789-99. [PMID: 11912222 DOI: 10.1093/jexbot/53.370.789] [Citation(s) in RCA: 124] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The rate of N uptake of crops is highly variable during crop development and between years and sites. However, under ample soil N availability, crop N accumulation is highly related to crop growth rate and to biomass accumulation. Critical N concentration has been defined as the minimum N concentration which allows maximum growth rate. Critical N concentration declines during crop growth. The relationship between critical N concentration and biomass accumulation over the growth period of a crop is broadly similar within major C(3) and C(4) cultivated species. Therefore, the critical N concentration concept is widely used in agronomy as the basis of the diagnosis of crop N status, and allows discrimination between situations of sub-optimal and supra-optimal N supply. The relationship between N and biomass accumulation in crops, relies on the interregulation of multiple crop physiological processes. Among these processes, N uptake, crop C assimilation and thus growth rate, and C and N allocation between organs and between plants, play a particular role. Under sub-optimal N supply, N uptake of the crop depends on soil mineral N availability and distribution, and on root distribution. Under ample N supply, N uptake largely depends on growth rate via internal plant regulation. Carbon assimilation of the crop is related to crop N through the distribution of N between mature leaves with consequences for leaf and canopy photosynthesis. However, although less commonly emphasized, carbon assimilation of the crop also depends on crop N through leaf area development. Therefore, crop growth rate fundamentally relies on the balance of N allocation between growing and mature leaves. Nitrogen uptake and distribution also depends on C allocation between organs and N composition of these organs. Within shoots, allocation of C to stems generally increases in relation to C allocation to the leaves over the crop growth period. Allocation of C and N between shoots and roots also changes to a large extent in relation to soil N and/or crop N. These alterations in C and N allocation between plant organs have implications, together with soil availability and carbon assimilation, on N uptake and distribution in crops. Therefore, N uptake and distribution in plants and crops involves many aspects of growth and development. Regulation of nitrogen assimilation needs to be considered in the context of these interregulatory processes.
Collapse
Affiliation(s)
- F Gastal
- Unité d'Ecophysiologie des Plantes Fourragères, INRA-UEPF, 86600 Lusignan, France.
| | | |
Collapse
|
31
|
de O Manes CL, Van Montagu M, Prinsen E, Goethals K, Holsters M. De novo cortical cell division triggered by the phytopathogen Rhodococcus fascians in tobacco. MOLECULAR PLANT-MICROBE INTERACTIONS : MPMI 2001; 14:189-95. [PMID: 11204782 DOI: 10.1094/mpmi.2001.14.2.189] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Plant growth, development, and morphology can be affected by several environmental stimuli and by specific interactions with phytopathogens. In many cases, plants respond to pathogenic stimuli by adapting their hormone levels. Here, the interaction between the phytopathogen Rhodococcus fascians and one of its host plants, tobacco, was analyzed phenotypically and molecularly. To elucidate the basis of the cell division modulation and shoot primordia initiation caused by R. fascians, tobacco plants were infected at leaf axils and shoot apices. Adventitious meristems that gave rise to multiple-shoot primordia (leafy galls) were formed. The use of a transgenic line carrying the mitotic CycB1 promoter fused to the reporter gene coding for beta-glucuronidase from Escherichia coli (uidA), revealed that stem cortical cells were stimulated to divide in an initial phase of the leafy gall ontogenesis. Local cytokinin and auxin levels throughout the infection process as well as modulation of expression of the cell cycle regulator gene Nicta;CycD3;2 are discussed.
Collapse
Affiliation(s)
- C L de O Manes
- Department of Plantengenetica, Vlaams Interuniversitair Instituut voor Biotechnologie, Universiteit Gent, Belgium
| | | | | | | | | |
Collapse
|
32
|
Schnyder, de Visser R. Fluxes of reserve-derived and currently assimilated carbon and nitrogen in perennial ryegrass recovering from defoliation. The regrowing tiller and its component functionally distinct zones. PLANT PHYSIOLOGY 1999; 119:1423-36. [PMID: 10198102 PMCID: PMC32028 DOI: 10.1104/pp.119.4.1423] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/1998] [Accepted: 01/07/1999] [Indexed: 05/20/2023]
Abstract
The quantitative significance of reserves and current assimilates in regrowing tillers of severely defoliated plants of perennial ryegrass (Lolium perenne L.) was assessed by a new approach, comprising 13C/12C and 15N/14N steady-state labeling and separation of sink and source zones. The functionally distinct zones showed large differences in the kinetics of currently assimilated C and N. These are interpreted in terms of "substrate" and "tissue" flux among zones and C and N turnover within zones. Tillers refoliated rapidly, although C and N supply was initially decreased. Rapid refoliation was associated with (a) transient depletion of water-soluble carbohydrates and dilution of structural biomass in the immature zone of expanding leaves, (b) rapid transition to current assimilation-derived growth, and (c) rapid reestablishment of a balanced C:N ratio in growth substrate. This balance (C:N, approximately 8.9 [w/w] in new biomass) indicated coregulation of growth by C and N supply and resulted from complementary fluxes of reserve- and current assimilation-derived C and N. Reserves were the dominant N source until approximately 3 d after defoliation. Amino-C constituted approximately 60% of the net influx of reserve C during the first 2 d. Carbohydrate reserves were an insignificant source of C for tiller growth after d 1. We discuss the physiological mechanisms contributing to defoliation tolerance.
Collapse
Affiliation(s)
- Schnyder
- Chair of Grassland Science, Technische Universitat Munchen, D-85350 Freising-Weihenstephan, Germany (H.S.)
| | | |
Collapse
|
33
|
Ben-Haj-Salah H, Tardieu F. Temperature Affects Expansion Rate of Maize Leaves without Change in Spatial Distribution of Cell Length (Analysis of the Coordination between Cell Division and Cell Expansion). PLANT PHYSIOLOGY 1995; 109:861-870. [PMID: 12228638 PMCID: PMC161387 DOI: 10.1104/pp.109.3.861] [Citation(s) in RCA: 105] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
We have analyzed the way in which temperature affects leaf elongation rate of maize (Zea mays L.) leaves, while spatial distributions (observed at a given time) of cell length and of proportion of cells in DNA replication are unaffected. We have evaluated, in six growth chamber experiments with constant temperatures (from 13 to 34[deg]C) and two field experiments with fluctuating temperatures, (a) the spatial distributions of cell length and of leaf elongation rate, and (b) the distribution of cell division, either by using the continuity equation or by flow cytometry. Leaf elongation rate was closely related to meristem temperature, with a common relationship in the field and in the growth chamber. Cell division and cell elongation occurred in the first 20 and 60 mm after the ligule, respectively, at all temperatures. Similar quantitative responses to temperature were observed for local cell division and local tissue expansion rates (common x intercept and normalized slope), and both responses were spatially uniform over the whole expanding zone (common time courses in thermal time). As a consequence, faster cell elongation matched faster cell division rate and faster elongation was compensated for by faster cell displacement, resulting in temperature-invariant profiles of cell length and of proportion of dividing cells. Cell-to-cell communication, therefore, was not necessary to account for coordination.
Collapse
Affiliation(s)
- H. Ben-Haj-Salah
- Institut National de la Recherche Agronomique, Laboratoire d'Ecophysiologie des Plantes sous Stress Environnementaux, 2 place Viala, 34060 Montpellier, France
| | | |
Collapse
|
34
|
Spollen WG, Nelson CJ. Response of Fructan to Water Deficit in Growing Leaves of Tall Fescue. PLANT PHYSIOLOGY 1994; 106:329-336. [PMID: 12232332 PMCID: PMC159531 DOI: 10.1104/pp.106.1.329] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Changes in dry matter and water-soluble carbohydrate components, especially fructan, were examined in the basal 25 mm of expanding leaf blades of tall fescue (Festuca arundinacea Schreb.) to assess their roles in plant response to water deficit. Water was withheld from vegetative plants grown in soil in controlled-environment chambers. As stress progressed, leaf elongation rate decreased sooner in the light period than it did in the dark period. The decrease in growth rate in the dark period was associated with a decrease in local relative elongation rates and a shortening of the elongation zone from about 25 mm (control) to 15 mm. Dry matter content of the leaf base increased 23% during stress, due mainly to increased water-soluble carbohydrate near the ligule and to increased water-soluble, carbohydrate-free dry matter at distal positions. Sucrose content increased 258% in the leaf base, but especially (over 4-fold) within 10 mm of the ligule. Hexose content increased 187% in the leaf base. Content of total fructan decreased to 69% of control, mostly in regions farther from the ligule. Fructan hydrolysis could account for the hexose accumulated. Stress caused the osmotic potential to decrease throughout the leaf base, but more toward the ligule. With stress there was 70% less direct contribution of low-degree-of-polymerization fructan to osmotic potential in the leaf base, but that for sucrose and hexose increased 96 and 67%, respectively. Thus, fructan metabolism is involved but fructan itself contributes only indirectly to osmotic adjustment.
Collapse
Affiliation(s)
- W. G. Spollen
- Department of Agronomy, University of Missouri, Columbia, Missouri 65211
| | | |
Collapse
|