Combined effects of drought and high temperature on photosynthetic characteristics in four winter wheat genotypes

0491726 - ÚVGZ 2019 RIV NL eng J - Článek v odborném periodiku
Urban, Otmar - Hlaváčová, Marcela - Klem, Karel - Surá, Kateřina - Rapantová, Barbora - Smutná, P. - Horáková, V. - Hlavinka, Petr - Škarpa, P. - Trnka, Miroslav
Combined effects of drought and high temperature on photosynthetic characteristics in four winter wheat genotypes.
Field Crops Research. Roč. 223, JUN (2018), s. 137-149. ISSN 0378-4290. E-ISSN 1872-6852
Grant CEP: GA MŠMT(CZ) LO1415; GA MŠMT(CZ) EF16_013/0001609
Výzkumná infrastruktura: CzeCOS II - 90061
Institucionální podpora: RVO:86652079
Klíčová slova: stress tolerance * stomatal conductance * abiotic stress * carbon-dioxide * climate-change * water-deficit * responses * plants * yield * barley * Chlorophyll fluorescence * Heat stress * Interactive effect * Photosynthesis * Triticum aestivum * Water use efficiency
Obor OECD: Agronomy, plant breeding and plant protection
Impakt faktor: 3.868, rok: 2018

Terrestrial ecosystems are expected to experience more intense and longer drought and heat-waves in the future. How these environmental factors and their interaction influence photosynthetic activity and water use efficiency remains, however, an open question. Since the photosynthetic activity determines yield response, we investigated gas-exchange and chlorophyll fluorescence traits of flag leaves in four winter wheat cultivars, including two genotypes widely grown in Central Europe and two genotypes considered as drought tolerant. Pot grown plants were cultivated under natural field conditions until anthesis (DC 61). Subsequently, the plants were exposed to a set of temperature regimes with daily maxima of 26-41 degrees C (temperature treatment) and maximum soil water holding capacity above 70% and below 30% (drought treatment) using laboratory growth chambers. Primary photochemical reactions after 7 and 14 days of acclimation, measured as maximum quantum yield of photosystem II photochemistry and total chlorophyll content, showed typical interactions of temperature and water availability resulting in an amplified response under combined influence of drought and temperatures above 35 degrees C. In contrast, drought and temperature treatment had only minor effects on content of epidermal flavonols. A dominant effect of drought over temperature on stomatal conductance (G(Smax)) was observed. Although substantial genotype-specific responses were found, reduced stomatal conductance resulted in significant decrease in light-saturated rates of CO2 assimilation (A(max)) in all genotypes studied. The G(Smax)-A(max) relationship, however, revealed limitation of CO2 uptake by other, non-stomatal processes at temperatures above 32 degrees C, particularly in the sensitive genotypes. Strong interaction of combined drought and temperature treatments was found on water use efficiency (WUE). Decline in WUE with increasing temperature was steeper in water-deficit than well-watered plants of all genotypes studied. Our results thus document a strong interactive effect of elevated temperature and drought on photosynthetic carbon uptake. Detected thresholds of sensitivity to combined drought and heat stress will contribute to improved modelling of wheat growth and production under expected future climate conditions.
Trvalý link: http://hdl.handle.net/11104/0285352