Dynamic responses of gas exchange and photochemistry to heat interference during drought in wheat and sorghum

Zhu, Lingling, Cernusak, Lucas A., and Song, Xin (2020) Dynamic responses of gas exchange and photochemistry to heat interference during drought in wheat and sorghum. Functional Plant Biology, 47 (7). pp. 611-627.

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Drought and heat stress significantly affect crop growth and productivity worldwide. It is unknown how heat interference during drought affects physiological processes dynamically in crops. Here we focussed on gas exchange and photochemistry in wheat and sorghum in response to simulated heat interference via +15 degrees C of temperature during similar to 2 week drought and re-watering. Results showed that drought decreased net photosynthesis (A(net)), stomatal conductance (g(s)), maximum velocity of ribulose-1, 5-bisphosphate carboxylase/oxygenase carboxylation (V-cmax) and electron transport rate (J) in both wheat and sorghum. Heat interference did not further reduce A(net) or g(s). Drought increased non-photochemical quenching (phi(npq)), whereas heat interference decreased phi(npq). The delta C-13 of leaf, stem and roots was higher in drought-treated wheat but lower in drought-treated sorghum. The results suggest that (1) even under drought conditions wheat and sorghum increased or maintained g(s) for transpirational cooling to alleviate negative effects by heat interference; (2) non-photochemical quenching responded differently to drought and heat stress; (3) wheat and sorghum responded in opposing patterns in delta C-13. These findings point to the importance of stomatal regulation under heat crossed with drought stress and could provide useful information on development of better strategies to secure crop production for future climate change.

Item ID: 63570
Item Type: Article (Research - C1)
ISSN: 1445-4416
Keywords: chlorophyll fluorescence, C-4, high temperature, photosynthesis, stable isotope, water deficit
Copyright Information: (C) CSIRO 2020
Funders: Science and Technology Innovation Commission of the Shenzhen City (STICSC), National Natural Science Foundation of China (NNSFC), China Postdoctoral Science Foundation (CPSF)
Projects and Grants: STICSC Shenzhen Municipal Peacock Team Program KQTD201703271516592, NNSFC 31770435, CPSF 2019M652760
Date Deposited: 24 Jun 2020 07:40
FoR Codes: 31 BIOLOGICAL SCIENCES > 3108 Plant biology > 310806 Plant physiology @ 100%
SEO Codes: 82 PLANT PRODUCTION AND PLANT PRIMARY PRODUCTS > 8204 Summer Grains and Oilseeds > 820404 Sorghum @ 50%
82 PLANT PRODUCTION AND PLANT PRIMARY PRODUCTS > 8205 Winter Grains and Oilseeds > 820507 Wheat @ 50%
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