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Ribeiro IM, Vinson CC, Coca GC, Ferreira CDS, Franco AC, Williams TCR. Differences in the metabolic and functional mechanisms used to tolerate flooding in Guazuma ulmifolia (Lam.) from flood-prone Amazonian and dry Cerrado savanna populations. Tree Physiol 2022; 42:2116-2132. [PMID: 35640151 DOI: 10.1093/treephys/tpac059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/26/2022] [Accepted: 05/19/2022] [Indexed: 06/15/2023]
Abstract
Flood tolerance is crucial to the survival of tree species subject to long periods of flooding, such as those present in the Amazonian várzea. Tolerance can be mediated by adjustments of metabolism, physiology and morphology, reinforcing the need to investigate the physiological and biochemical mechanisms used by tropical tree species to survive this stress. Moreover, such mechanisms may vary between populations that are subjected to differences in the frequency of flooding events. Here, we aimed to identify the mechanisms used by two populations of the tropical tree Guazuma ulmifolia (Lam.) to tolerate flooding: an Amazonian population frequently exposed to flooding and a Cerrado population, adapted to a dry environment. Young plants were subjected to a flooding of the roots and lower stem for 32 days, followed by 17 days of recovery. Amazonian plants exhibited greater increases in shoot length and higher maximum photosynthetic rate (Amax) compared with non-flooded plants from 7 days of flooding onwards, whereas increased Amax occurred later in flooded Cerrado plants and was not accompanied by increased shoot length. Lactate accumulated in roots of Cerrado plants after 24 h flooding, together with transcripts coding for lactate dehydrogenase in roots of both Cerrado and Amazonian plants. After 7 days of flooding, lactate decreased and alcohol dehydrogenase activity increased transiently, together with concentrations of alanine, γ-aminobutyric acid and succinate, indicating activation of metabolic processes associated with low oxygen availability. Other amino acids also increased in flooded Cerrado plants, revealing more extensive metabolic changes than in Amazonian plants. Wetland and dryland populations of G. ulmifolia revealed the great capacity to tolerate flooding stress through a suite of alterations in photosynthetic gas exchange and metabolism. However, the integrated physiological, biochemical and molecular analyses realized here indicated that wetland plants acclimatized more efficiently with increased shoot elongation and more rapid restoration of normal metabolism.
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Affiliation(s)
- Isadora M Ribeiro
- Department of Botany, University of Brasília, Institute of Biological Sciences, Campus Darcy Ribeiro, Asa Norte, Brasília DF 70910-900, Brazil
| | - Christina C Vinson
- Department of Botany, University of Brasília, Institute of Biological Sciences, Campus Darcy Ribeiro, Asa Norte, Brasília DF 70910-900, Brazil
| | - Guilherme C Coca
- Department of Botany, University of Brasília, Institute of Biological Sciences, Campus Darcy Ribeiro, Asa Norte, Brasília DF 70910-900, Brazil
| | - Cristiane da S Ferreira
- Department of Botany, University of Brasília, Institute of Biological Sciences, Campus Darcy Ribeiro, Asa Norte, Brasília DF 70910-900, Brazil
| | - Augusto C Franco
- Department of Botany, University of Brasília, Institute of Biological Sciences, Campus Darcy Ribeiro, Asa Norte, Brasília DF 70910-900, Brazil
| | - Thomas C R Williams
- Department of Botany, University of Brasília, Institute of Biological Sciences, Campus Darcy Ribeiro, Asa Norte, Brasília DF 70910-900, Brazil
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Proença CEB, Tuler AC, Lucas EJ, Vasconcelos TNDC, de Faria JEQ, Staggemeier VG, de-Carvalho PS, Forni-Martins ER, Inglis PW, da Mata LR, da Costa IR. Diversity, phylogeny and evolution of the rapidly evolving genus Psidium L. (Myrtaceae, Myrteae). Ann Bot 2022; 129:367-388. [PMID: 35034117 PMCID: PMC8944734 DOI: 10.1093/aob/mcac005] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 01/14/2022] [Indexed: 06/14/2023]
Abstract
BACKGROUND AND AIMS Psidium is the fourthth largest genus of Myrtaceae in the Neotropics. Psidium guajava is widely cultivated in the tropics for its edible fruit. It is commercially under threat due to the disease guava decline. Psidium cattleyanum is one of the 100 most invasive organisms in the world. Knowledge of the phylogenetic relationships within Psidium is poor. We aim to provide a review of the biology, morphology and ecology of Psidium, a phylogenetic tree, an infrageneric classification and a list of species. METHODS Morphological and geographic data were obtained by studying Psidium in herbaria and in the field between 1988 and 2020. Forty-six herbaria were visited personally. A database of approx. 6000 specimens was constructed, and the literature was reviewed. Thirty species (about a third of the species in the genus) were sampled for molecular phylogenetic inference. Two chloroplast (psbA-trnH and ndhF) and two nuclear (external transcribed spacer and internal transcribed spacer) regions were targeted. Phylogenetic trees were constructed using maximum likelihood (ML; RaxML) and Bayesian inference (BI; MrBayes). KEY RESULTS Psidium is a monophyletic genus with four major clades recognized as sections. Section Psidium (ten species), to which P. guajava belongs, is sister to the rest of the genus; it is widespread across the Neotropics. Section Obversifolia (six species; restricted to the Brazilian Atlantic Forest), which includes P. cattleyanum, is sister to the innermost clade composed of sister sections Apertiflora (31 species; widespread but most diverse in the Brazilian Atlantic Forest) + Mitranthes (26 species; widespread in dry forests and probably diverse in the Caribbean). Characters associated with diversification within Psidium are discussed. CONCLUSIONS Research on pre-foliation, colleters, leaf anatomy, leaf physiology, staminal development, placentation and germination associated with the anatomy of the opercular plug is desirable. Studies are biased towards sections Psidium and Obversifolia, with other sections poorly known.
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Affiliation(s)
| | - Amélia Carlos Tuler
- Instituto Nacional da Mata Atlântica, Av. José Ruschi 4, Santa Teresa, ES, CEP, Brazil
| | | | | | | | - Vanessa Graziele Staggemeier
- Departamento de Ecologia, Universidade Federal do Rio Grande do Norte, R. das Biociências, Lagoa Nova, Natal, RN, CEP, Brazil
| | | | | | | | - Lorena Ramos da Mata
- Empresa Brasileira de Pesquisa Agropecuária, Recursos Genéticos e Biotecnologia (EMBRAPA CENARGEN)
, SAIN Parque Rural, W5, Asa Norte, Brasília, DF, Brazil
| | - Itayguara Ribeiro da Costa
- Departamento de Biologia, Universidade Federal do Ceará, Campus do Pici Bloco 906, Fortaleza, CE, Brazil
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Ambastha V, Sopory SK, Tripathy BC, Tiwari BS. Salt induced programmed cell death in rice: evidence from chloroplast proteome signature. Funct Plant Biol 2020; 48:8-27. [PMID: 32702286 DOI: 10.1071/fp19356] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/09/2019] [Accepted: 07/01/2020] [Indexed: 06/11/2023]
Abstract
Soil salinity, depending on its intensity, drives a challenged plant either to death, or survival with compromised productivity. On exposure to moderate salinity, plants can often survive by sacrificing some of their cells 'in target' following a route called programmed cell death (PCD). In animals, PCD has been well characterised, and involvement of mitochondria in the execution of PCD events has been unequivocally proven. In plants, mechanistic details of the process are still in grey area. Previously, we have shown that in green tissues of rice, for salt induced PCD to occur, the presence of active chloroplasts and light are equally important. In the present work, we have characterised the chloroplast proteome in rice seedlings at 12 and 24 h after salt exposure and before the time point where the signature of PCD was observed. We identified almost 100 proteins from chloroplasts, which were divided in to 11 categories based on the biological functions in which they were involved. Our results concerning the differential expression of chloroplastic proteins revealed involvement of some novel candidates. Moreover, we observed maximum phosphorylation pattern of chloroplastic proteins at an early time point (12 h) of salt exposure.
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Affiliation(s)
- Vivek Ambastha
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India
| | - Sudhir K Sopory
- Plant Molecular Biology, International Centre of Genetic Engineering and Biotechnology, New Delhi 110067, India
| | - Baishnab C Tripathy
- School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India; and Corresponding author. ; ;
| | - Budhi Sagar Tiwari
- Institute of Advanced Research, Gandhinagar, Gujrat 482007, India; and Corresponding author. ; ;
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Zhang Y, Zhao L, Xiao H, Chew J, Xiang J, Qian K, Fan X. Knockdown of a Novel Gene OsTBP2.2 Increases Sensitivity to Drought Stress in Rice. Genes (Basel) 2020; 11:E629. [PMID: 32521717 DOI: 10.3390/genes11060629] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 06/05/2020] [Accepted: 06/05/2020] [Indexed: 02/06/2023] Open
Abstract
Drought stress is a major environmental stress, which adversely affects the biological and molecular processes of plants, thereby impairing their growth and development. In the present study, we found that the expression level of OsTBP2.2 which encodes for a nucleus-localized protein member belonging to transcription factor IID (TFIID) family, was significantly induced by polyethylene glycol (PEG) treatment. Therefore, knockdown mutants of OsTBP2.2 gene were generated to investigate the role of OsTBP2.2 in rice response to drought stress. Under the condition of drought stress, the photosynthetic rate, transpiration rate, water use efficiency, and stomatal conductance were significantly reduced in ostbp2.2 lines compared with wild type, Dongjin (WT-DJ). Furthermore, the RNA-seq results showed that several main pathways involved in "MAPK (mitogen-activated protein kinase) signaling pathway", "phenylpropanoid biosynthesis", "defense response" and "ADP (adenosine diphosphate) binding" were altered significantly in ostbp2.2. We also found that OsPIP2;6, OsPAO and OsRCCR1 genes were down-regulated in ostbp2.2 compared with WT-DJ, which may be one of the reasons that inhibit photosynthesis. Our findings suggest that OsTBP2.2 may play a key role in rice growth and the regulation of photosynthesis under drought stress and it may possess high potential usefulness in molecular breeding of drought-tolerant rice.
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Zúñiga-Feest A, Bustos-Salazar A, Alves F, Martinez V, Smith-Ramírez C. Physiological and morphological responses to permanent and intermittent waterlogging in seedlings of four evergreen trees of temperate swamp forests. Tree Physiol 2017; 37:779-789. [PMID: 28338952 DOI: 10.1093/treephys/tpx023] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2016] [Accepted: 02/22/2017] [Indexed: 06/06/2023]
Abstract
Waterlogging decreases a plant's metabolism, stomatal conductance (gs) and photosynthetic rate (A); however, some evergreen species show acclimation to waterlogging. By studying both the physiological and morphological responses to waterlogging, the objective of this study was to assess the acclimation capacity of four swamp forest species that reside in different microhabitats. We proposed that species (Luma apiculata [D.C.] Burret. and Drimys winteri J.R. et G. Forster.) abundant in seasonally and intermittently waterlogged areas (SIWA) would have a higher acclimation capacity than species abundant in the inner swamp (Blepharocalyx cruckshanksii [H et A.] Mied. and Myrceugenia exsucca [D.C.] Berg.) where permanent waterlogging occurs (PWA); it was expected that the species from SIWA would maintain leaf expansion and gas exchange rates during intermittent waterlogging treatments. Conversely, we expected that PWA species would have higher constitutive waterlogging tolerance, and this would be reflected in the formation of lenticels and adventitious roots. Over the course of 2 months, we subjected seedlings to different waterlogging treatments: (i) permanent (sudden, SW), (ii) intermittent (gradual) or (iii) control (field capacity, C). Survival after waterlogging was high (≥80%) for all species and treatments, and only the growth rate of D. winteri subjected to SW was affected. Drimys winteri plants had low, but constant A and g during both waterlogging treatments. Conversely, L. apiculata had the highest A and g values, and g increased significantly during the first several days of waterlogging. In general, seedlings of all species subjected to waterlogging produced more adventitious roots and fully expanded leaves and had higher specific leaf area (SLA) and stomatal density (StD) than seedlings in the C treatment. From the results gathered here, we partially accept our hypothesis as all species showed high tolerance to waterlogging, maintained growth, and had increased A or g during different time points of waterlogging. Differences in leaf (SLA) and stomata functioning (gs, StD) plasticity likely allows plants to maintain positive carbon gains when waterlogging occurs. The species-specific differences found here were not entirely related to microhabitat distribution.
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Affiliation(s)
- Alejandra Zúñiga-Feest
- Laboratorio de Biología vegetal, Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
- Centro de investigaciones en Suelo volcánicos, CISVo, Universidad Austral de Chile, Valdivia, Chile
| | - Angela Bustos-Salazar
- Laboratorio de Biología vegetal, Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile
- Escuela de Graduados Facultad de Ciencias Forestales, Universidad Austral de Chile, Chile
- Centro de Ciencia del Clima y Resiliencia (CR), Santiago, Chile
| | - Fernanda Alves
- Laboratorio de Biología vegetal, Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia , Chile
| | - Vanessa Martinez
- Laboratorio de Biología vegetal, Instituto de Ciencias Ambientales y Evolutivas, Facultad de Ciencias, Universidad Austral de Chile, Casilla 567, Valdivia , Chile
| | - Cecilia Smith-Ramírez
- Instituto de Ecología y Biodiversidad (IEB), Universidad de Chile, Casilla 653, Santiago, Chile
- Instituto de Bosques y Territorio, Facultad de Ciencias Forestales y Recursos Naturales, Universidad Austral de Chile, Valdivia, Chile
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Kreuzwieser J, Rennenberg H. Molecular and physiological responses of trees to waterlogging stress. Plant Cell Environ 2014; 37:2245-59. [PMID: 24611781 DOI: 10.1111/pce.12310] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Revised: 02/09/2014] [Accepted: 02/12/2014] [Indexed: 05/23/2023]
Abstract
One major effect of global climate change will be altered precipitation patterns in many regions of the world. This will cause a higher probability of long-term waterlogging in winter/spring and flash floods in summer because of extreme rainfall events. Particularly, trees not adapted at their natural site to such waterlogging stress can be impaired. Despite the enormous economic, ecological and social importance of forest ecosystems, the effect of waterlogging on trees is far less understood than the effect on many crops or the model plant Arabidopsis. There is only a handful of studies available investigating the transcriptome and metabolome of waterlogged trees. Main physiological responses of trees to waterlogging include the stimulation of fermentative pathways and an accelerated glycolytic flux. Many energy-consuming, anabolic processes are slowed down to overcome the energy crisis mediated by waterlogging. A crucial feature of waterlogging tolerance is the steady supply of glycolysis with carbohydrates, particularly in the roots; stress-sensitive trees fail to maintain sufficient carbohydrate availability resulting in the dieback of the stressed tissues. The present review summarizes physiological and molecular features of waterlogging tolerance of trees; the focus is on carbon metabolism in both, leaves and roots of trees.
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Affiliation(s)
- Jürgen Kreuzwieser
- Institute of Forest Science, Chair of Tree Physiology, Albert-Ludwigs-Universität Freiburg, Freiburg, 79110, Germany
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Herrera A. Responses to flooding of plant water relations and leaf gas exchange in tropical tolerant trees of a black-water wetland. Front Plant Sci 2013; 4:106. [PMID: 23641246 PMCID: PMC3640197 DOI: 10.3389/fpls.2013.00106] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2013] [Accepted: 04/08/2013] [Indexed: 05/17/2023]
Abstract
This review summarizes the research on physiological responses to flooding of trees in the seasonal black-water wetland of the Mapire River in Venezuela. Inter-annual variability was found during 8 years of sampling, in spite of which a general picture emerged of increased stomatal conductance (gs) and photosynthetic rate (PN) during the flooded period to values as high as or higher than in plants in drained wet soil. Models explaining the initial inhibitory responses and the acclimation to flooding are proposed. In the inhibitory phase of flooding, hypoxia generated by flooding causes a decrease in root water absorption and stomatal closure. An increase with flooding in xylem water potential (ψ) suggests that flooding does not cause water deficit. The PN decreases due to changes in relative stomatal and non-stomatal limitations to photosynthesis; an increase in the latter is due to reduced chlorophyll and total soluble protein content. Total non-structural carbohydrates (TNC) accumulate in leaves but their content begins to decrease during the acclimatized phase at full flooding, coinciding with the resumption of high gs and PN. The reversal of the diminution in gs is associated, in some but not all species, to the growth of adventitious roots. The occurrence of morpho-anatomical and biochemical adaptations which improve oxygen supply would cause the acclimation, including increased water absorption by the roots, increased rubisco and chlorophyll contents and ultimately increased PN. Therefore, trees would perform as if flooding did not signify a stress to their physiology.
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Affiliation(s)
- A. Herrera
- Centro de Botánica Tropical, Instituto de Biología Experimental, Universidad Central de VenezuelaCaracas, Venezuela
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Dalmolin ÂC, Dalmagro HJ, Lobo FDA, Antunes Junior MZ, Ortíz CER, Vourlitis GL. Effects of flooding and shading on growth and gas exchange of Vochysia divergens Pohl (Vochysiaceae) of invasive species in the Brazilian Pantanal. ACTA ACUST UNITED AC 2012. [DOI: 10.1590/s1677-04202012000200001] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Gimeno V, Syvertsen JP, Simón I, Nieves M, Díaz-López L, Martínez V, García-Sánchez F. Physiological and morphological responses to flooding with fresh or saline water in Jatropha curcas. Environmental and Experimental Botany 2012. [PMID: 0 DOI: 10.1016/j.envexpbot.2011.12.014] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
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Medina CL, Sanches MC, Tucci MLS, Sousa CAF, Cuzzuol GRF, Joly CA. Erythrina speciosa (Leguminosae-Papilionoideae) under soil water saturation: morphophysiological and growth responses. Ann Bot 2009; 104:671-680. [PMID: 19581282 PMCID: PMC2729630 DOI: 10.1093/aob/mcp159] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2009] [Revised: 03/18/2009] [Accepted: 06/01/2009] [Indexed: 05/28/2023]
Abstract
BACKGROUND AND AIMS Erythrina speciosa is a Neotropical tree that grows mainly in moist habitats. To characterize the physiological, morphological and growth responses to soil water saturation, young plants of E. speciosa were subjected experimentally to soil flooding. METHODS Flooding was imposed from 2 to 4 cm above the soil surface in water-filled tanks for 60 d. Non-flooded (control) plants were well watered, but never flooded. The net CO(2) exchange (A(CO2)), stomatal conductance (g(s)) and intercellular CO(2) concentration (C(i)) were assessed for 60 d. Soluble sugar and free amino acid concentrations and the proportion of free amino acids were determined at 0, 7, 10, 21, 28 and 45 d of treatments. After 28, 45 and 60 d, dry masses of leaves, stems and roots were determined. Stem and root cross-sections were viewed using light microscopy. KEY RESULTS The A(CO2) and g(s) were severely reduced by flooding treatment, but only for the first 10 d. The soluble sugars and free amino acids increased until the tenth day but decreased subsequently. The content of asparagine in the roots showed a drastic decrease while those of alanine and gamma-aminobutyric increased sharply throughout the first 10 d after flooding. From the 20th day on, the flooded plants reached A(CO2) and g(s) values similar to those observed for non-flooded plants. These events were coupled with the development of lenticels, adventitious roots and aerenchyma tissue of honeycomb type. Flooding reduced the growth rate and altered carbon allocation. The biomass allocated to the stem was higher and the root mass ratio was lower for flooded plants when compared with non-flooded plants. CONCLUSIONS Erythrina speciosa showed 100 % survival until the 60th day of flooding and was able to recover its metabolism. The recovery during soil flooding seems to be associated with morphological alterations, such as development of hypertrophic lenticels, adventitious roots and aerenchyma tissue, and with the maintenance of neutral amino acids in roots under long-term exposure to root-zone O(2) deprivation.
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Affiliation(s)
- Camilo L. Medina
- Departmento de Biologia Vegetal, IB, Universidade Estadual de Campinas, CP 6109, 13083-970 Campinas, SP, Brazil
| | - Maria Cristina Sanches
- Universidade Federal de Uberlândia, Instituto de Biologia, CP 593, 38400-902 Uberlândia, MG, Brazil
| | | | - Carlos A. F. Sousa
- EMBRAPA Meio-Norte, Av. Duque de Caxias, CP 5650, 64006-220 Teresina, PI, Brazil
| | - Geraldo Rogério F. Cuzzuol
- Universidade Federal do Espírito Santo, Av. Fernando Ferrari 514, 29060-900 Campos de Goiabeiras, ES, Brazil
| | - Carlos A. Joly
- Departmento de Biologia Vegetal, IB, Universidade Estadual de Campinas, CP 6109, 13083-970 Campinas, SP, Brazil
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Parolin P. Submerged in darkness: adaptations to prolonged submergence by woody species of the Amazonian floodplains. Ann Bot 2009; 103:359-76. [PMID: 19001429 PMCID: PMC2707320 DOI: 10.1093/aob/mcn216] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Revised: 06/02/2008] [Accepted: 09/01/2008] [Indexed: 05/19/2023]
Abstract
BACKGROUND In Amazonian floodplain forests, >1000 tree species grow in an environment subject to extended annual submergence which can last up to 9 months each year. Water depth can reach 10 m, fully submerging young and also adult trees, most of which reproduce during the flood season. Complete submergence occurs regularly at the seedling or sapling stage for many species that colonize low-lying positions in the flooding gradient. Here hypoxic conditions prevail close to the water surface in moving water, while anaerobic conditions are common in stagnant pools. Light intensities in the floodwater are very low. QUESTIONS AND AIMS Despite a lack of both oxygen and light imposed by submergence for several months, most leafed seedlings survive. Furthermore, underwater growth has also been observed in several species in the field and under experimental conditions. The present article assesses how these remarkable plants react to submergence and discusses physiological mechanisms and anatomical adaptations that may explain their success.
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Affiliation(s)
- Pia Parolin
- Max-Planck-Institute for Evolutionary Biology, Tropical Ecology, PO Box 165, D-24302 Plön, Germany.
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Herrera A, Tezara W, Marín O, Rengifo E. Stomatal and non-stomatal limitations of photosynthesis in trees of a tropical seasonally flooded forest. Physiol Plant 2008; 134:41-48. [PMID: 18444960 DOI: 10.1111/j.1399-3054.2008.01099.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
Trees in the flooded forest of the Mapire River in Venezuela suffer a decrease in photosynthetic rate (A) when flood begins, which is reverted at maximum flood. Changes in A are accompanied by similar changes in stomatal conductance (g(s)), and the possibility of changes in photosynthetic capacity is not ruled out. In order to understand how relative stomatal and non-stomatal limitations of photosynthesis are affected by flooding, we studied the seasonal changes in A and its response to intercellular CO(2) concentration in trees of Campsiandra laurifolia, Symmeria paniculata, Acosmium nitens and Eschweilera tenuifolia. Flooding caused in trees of C. laurifolia and S. paniculata a reduction in A, g(s), carboxylation efficiency and total soluble protein (TSP), whereas gas exchange in A. nitens and E. tenuifolia was more sensitive to drought. Under flooding, relative stomatal limitation (L(s)) was on average half the highest, and relative non-stomatal limitation (L(ns)) increased from the dry season to flooding. Under full flood, A, g(s) and TSP regained high values. A was positively correlated to light-saturated electron transport rate, suggesting that part of the decrease in A under flooding was due to impairment of photosynthetic capacity. Under flooding, not only stomatal closure but also increased L(ns) causes a reduction in photosynthesis of all four species, and a process of acclimation as flooding progresses allows gas exchange and related variables to regain high values.
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Affiliation(s)
- Ana Herrera
- Centro de Botánica Tropical, Instituto de Biología Experimental, Universidad Central de Venezuela, Apartado, Caracas, Venezuela.
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Abstract
Thirteen new triterpenoid saponins (1-13) were isolated from the aerial parts of Campsiandra guayanensis. Their structures were elucidated by 1D and 2D NMR experiments including 1D-TOCSY, DQF-COSY, ROESY, HSQC, and HMBC spectroscopy, as well as ESIMS analysis. The aglycon moieties of 1-10 were assigned as oleanane derivatives and those of 11-13 as lupane derivatives.
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Affiliation(s)
- Alessandra Braca
- Dipartimento di Chimica Bioorganica e Biofarmacia, Università di Pisa, Via Bonanno 33, 56126 Pisa, Italy.
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