Shenzhen Key Laboratory of Marine Biological Resources and Ecological Environment, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, 518060, China; and Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen University, Shenzhen, 518060, China.
College of Science and Engineering, James Cook University, Cairns, Australia.
Funct Plant Biol. 2020 Jun;47(7):611-627. doi: 10.1071/FP19242.
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°C of temperature during ~2 week drought and re-watering. Results showed that drought decreased net photosynthesis (Anet), stomatal conductance (gs), maximum velocity of ribulose-1, 5-bisphosphate carboxylase/oxygenase carboxylation (Vcmax) and electron transport rate (J) in both wheat and sorghum. Heat interference did not further reduce Anet or gs. Drought increased non-photochemical quenching (Φnpq), whereas heat interference decreased Φnpq. The δ13C 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 gs 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 δ13C. 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.
干旱和热应激显著影响全球作物的生长和生产力。目前尚不清楚干旱期间的热干扰如何动态影响作物的生理过程。在这里，我们专注于小麦和高粱在模拟热干扰下的气体交换和光化学响应，即在约 2 周的干旱和再浇水期间，温度升高 +15°C。结果表明，干旱降低了小麦和高粱的净光合速率（Anet）、气孔导度（gs）、核酮糖-1,5-二磷酸羧化酶/加氧酶羧化的最大速率（Vcmax）和电子传递速率（J）。热干扰并没有进一步降低 Anet 或 gs。干旱增加了非光化学猝灭（Φnpq），而热干扰降低了 Φnpq。干旱处理的小麦叶片、茎和根的 δ13C 更高，而干旱处理的高粱的 δ13C 更低。结果表明：（1）即使在干旱条件下，小麦和高粱增加或维持 gs 以进行蒸腾冷却，以减轻热干扰的负面影响；（2）非光化学猝灭对干旱和热胁迫的响应不同；（3）小麦和高粱对 δ13C 的响应呈相反模式。这些发现表明在热胁迫与干旱胁迫交叉作用下，气孔调节的重要性，并为未来气候变化下保障作物生产的更好策略的发展提供了有用信息。
