Grain carbon isotopes indicate the ability of wheat plants to maintain enhanced intrinsic water-use efficiency even after short-term exposure to high temperatures and drought

0578883 - ÚVGZ 2024 RIV NL eng J - Journal Article
Pernicová, Natálie - Hlaváčová, Marcela - Findurová, Hana - Čáslavský, Josef - Urban, Otmar - Klem, Karel - Trnka, Miroslav
Grain carbon isotopes indicate the ability of wheat plants to maintain enhanced intrinsic water-use efficiency even after short-term exposure to high temperatures and drought.
Plant Physiology and Biochemistry. Roč. 205, DEC (2023), č. článku 108155. ISSN 0981-9428
R&D Projects: GA ČR(CZ) GA21-18532S; GA MŠMT(CZ) EH22_008/0004635
Research Infrastructure: CzeCOS IV - 90248
Institutional support: RVO:86652079
Keywords : abiotic stress * gas-exchange measurements * water-use efficiency * wheat grain * 13c isotope discrimination
OECD category: Agronomy, plant breeding and plant protection
Impact factor: 6.5, year: 2022
Method of publishing: Open access
https://www.sciencedirect.com/science/article/pii/S0981942823006666

Minimizing the impact of heat and drought on crop yields requires varieties with effective protective mechanisms. We tested the hypothesis that even a short-term high temperature amplifies the negative effects of reduced water availability on leaf gas-exchange, but can induce long-lasting improvement in plant water-use efficiency after the stress period. Accordingly, three common varieties of winter wheat (Triticum aestivum) were grown under field conditions. During the stem extension, the plants were exposed to distinct temperatures (daily maximum 26 vs. 38 °C), water availabilities (75% of field water capacity vs. permanent wilting point), and their combination for 14 days.
All treatments reduced light-saturated rates of CO2 assimilation and transpiration, particularly when heat and drought were combined. Drought enhanced water-use efficiency (WUE) in all varieties (31.4–36.4%), but not at high temperatures (decrease by 17–52%). Intrinsic WUE (iWUE), determined from the stable carbon isotope composition of grains, was enhanced by 7.9–37% in all treatments and varieties, however, not all changes were significant. The combination of heat and drought tended to increase total protein content in grains but reduced spike productivity. Noticeably, the strongest decline in spike productivity was observed in Elan – the variety displaying the smallest enhancement of iWUE, while it was negligible in Pannonia which shows the most pronounced improvement of iWUE. We conclude that even several hot and dry days can improve iWUE for the rest of the vegetation season. This improvement, however, does not necessarily lead to increased crop productivity possibly due to physiological trade-offs.
Permanent Link: https://hdl.handle.net/11104/0347804

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