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Wang Z, Liu J, Wang Y, Agathokleous E, Hamoud YA, Qiu R, Hong C, Tian M, Shaghaleh H, Guo X. Relationships between stable isotope natural abundances (δ 13C and δ 15N) and water use efficiency in rice under alternate wetting and drying irrigation in soils with high clay contents. Front Plant Sci 2022; 13:1077152. [PMID: 36531393 PMCID: PMC9756853 DOI: 10.3389/fpls.2022.1077152] [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] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/22/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Natural abundance of the stable isotope (δ13C and δ15N) in plants is widely used to indicate water use efficiency (WUE). However, soil water and texture properties may affect this relationship, which remains largely elusive. Therefore, the purpose of this study was to evaluate δ13C as affected by different combinations of alternate wetting and drying irrigation (AWD) with varied soil clay contents in different organs and whole plant and assess the feasibility of using δ13C and δ15N as a physiological indicator of whole-plant water use efficiency (WUEwhole-plant). Three AWD regimes, I100 (30 mm flooded when soil reached 100% saturation), I90 (30 mm flooded when reached 90% saturation) and I70 (30 mm flooded when reached 70% saturation) and three soil clay contents, 40% (S40), 50% (S50), and 60% (S60), were included. Observed variations in WUEwhole-plant did not conform to theoretical expectations of the organs δ13C (δ13Corgans) of plant biomass based on pooled data from all treatments. However, a positive relationship between δ13Cleaf and WUEET (dry biomass/evapotranspiration) was observed under I90 regime, whereas there were no significant relationships between δ13Corgans and WUEET under I100 or I70 regimes. Under I100, weak relationships between δ13Corgans and WUEET could be explained by (i) variation in C allocation patterns under different clay content, and (ii) relatively higher rate of panicle water loss, which was independent of stomatal regulation and photosynthesis. Under I70, weak relationships between δ13Corgans and WUEET could be ascribed to (i) bigger cracks induced by water-limited irrigation regime and high clay content soil, and (ii) damage caused by severe drought. In addition, a negative relationship was observed between WUEwhole-plant and shoot δ15N (δ15Nshoot) across the three irrigation treatments, indicating that WUEwhole-plant is tightly associated with N metabolism and N isotope discrimination in rice. Therefore, δ13C should be used cautiously as an indicator of rice WUEwhole-plant at different AWD regimes with high clay content, whereas δ15N could be considered an effective indicator of WUEwhole-plant.
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Affiliation(s)
- Zhenchang Wang
- College of Agricultural Science and Engineering, Hohai University, Nanjing, China
- Jiangsu Province Engineering Research Center for Agricultural Soil-Water Efficient Utilization, Carbon Sequestration and Emission Reduction, Nanjing, China
| | - Jinjing Liu
- College of Agricultural Science and Engineering, Hohai University, Nanjing, China
- Jiangsu Province Engineering Research Center for Agricultural Soil-Water Efficient Utilization, Carbon Sequestration and Emission Reduction, Nanjing, China
| | - Yaosheng Wang
- Institute of Environment and Sustainable Development in Agriculture, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Evgenios Agathokleous
- School of Applied Meteorology, Nanjing University of Information Science and Technology, Nanjing, China
| | - Yousef Alhaj Hamoud
- College of Agricultural Science and Engineering, Hohai University, Nanjing, China
- Department of Soil and Land Reclamation, Aleppo University, Aleppo, Syria
| | - Rangjian Qiu
- State Key Laboratory of Water Resources and Hydropower Engineering Science, Wuhan University, Wuhan, China
| | - Cheng Hong
- College of Agricultural Science and Engineering, Hohai University, Nanjing, China
- Jiangsu Province Engineering Research Center for Agricultural Soil-Water Efficient Utilization, Carbon Sequestration and Emission Reduction, Nanjing, China
| | - Minghao Tian
- College of Agricultural Science and Engineering, Hohai University, Nanjing, China
- Jiangsu Province Engineering Research Center for Agricultural Soil-Water Efficient Utilization, Carbon Sequestration and Emission Reduction, Nanjing, China
| | - Hiba Shaghaleh
- College of Environment, Hohai University, Nanjing, China
| | - Xiangping Guo
- College of Agricultural Science and Engineering, Hohai University, Nanjing, China
- Jiangsu Province Engineering Research Center for Agricultural Soil-Water Efficient Utilization, Carbon Sequestration and Emission Reduction, Nanjing, China
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Domergue J, Lalande J, Beucher D, Satour P, Abadie C, Limami AM, Tcherkez G. Experimental Evidence for Seed Metabolic Allometry in Barrel Medic (Medicago truncatula Gaertn.). Int J Mol Sci 2022; 23:8484. [PMID: 35955618 PMCID: PMC9369157 DOI: 10.3390/ijms23158484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 07/22/2022] [Accepted: 07/28/2022] [Indexed: 12/10/2022] Open
Abstract
Seed size is often considered to be an important trait for seed quality, i.e., vigour and germination performance. It is believed that seed size reflects the quantity of reserve material and thus the C and N sources available for post-germinative processes. However, mechanisms linking seed size and quality are poorly documented. In particular, specific metabolic changes when seed size varies are not well-known. To gain insight into this aspect, we examined seed size and composition across different accessions of barrel medic (Medicago truncatula Gaertn.) from the genetic core collection. We conducted multi-elemental analyses and isotope measurements, as well as exact mass GC–MS metabolomics. There was a systematic increase in N content (+0.17% N mg−1) and a decrease in H content (–0.14% H mg−1) with seed size, reflecting lower lipid and higher S-poor protein quantity. There was also a decrease in 2H natural abundance (δ2H), due to the lower prevalence of 2H-enriched lipid hydrogen atoms that underwent isotopic exchange with water during seed development. Metabolomics showed that seed size correlates with free amino acid and hexoses content, and anticorrelates with amino acid degradation products, disaccharides, malic acid and free fatty acids. All accessions followed the same trend, with insignificant differences in metabolic properties between them. Our results show that there is no general, proportional increase in metabolite pools with seed size. Seed size appears to be determined by metabolic balance (between sugar and amino acid degradation vs. utilisation for storage), which is in turn likely determined by phloem source metabolite delivery during seed development.
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