Drought stress reduces crop carbon gain due to delayed photosynthetic induction under fluctuating light conditions
Drought stress reduces crop carbon gain due to delayed photosynthetic induction under fluctuating light conditions
复制标题
干旱胁迫由于在波动的光照条件下光合诱导延迟而减少了作物的碳增益
DOI：
10.1111/ppl.13603
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发表时间：
2022
影响因子：
6.4
通讯作者：
Tanaka Yu
中科院分区：
文献类型：
--
作者：
Sakoda Kazuma;Taniyoshi Kazuki;Yamori Wataru;Tanaka Yu
干旱胁迫是制约作物生长和产量的主要因素。根据降水模式的不同，田间的可用水量可以在干旱和复水条件之间循环变化。同时，田间条件下的光强可以波动，在作物生长期间诱导动态光合作用和蒸腾作用。本研究旨在描述干旱和复水条件下两种主要作物水稻和大豆在波动光下的碳增益和水分利用。我们在波动光照条件下对水稻和大豆植株进行了气体交换测量，水稻和大豆植株经受了干旱处理（9-13天），包括不浇水和随后的再浇水处理（8-9天）。干旱胁迫显著降低了大豆的最大co2同化速率(A)，但对水稻没有影响。在干旱条件下，两种作物的光照均先增加后逐渐减少，导致水稻和大豆的稳态显著减少。此外，干旱胁迫延迟了两种作物的光合作用诱导，即使它对maximumA的影响相对较小。这些结果表明，干旱对光合作用的影响应基于诱导、最大和稳定状态来评估。干旱条件下气孔气体扩散导度降低导致光合作用诱导延迟，导致叶片在波动光条件下碳增益的大量损失。与此同时，干旱后再浇水，两种作物在波动光下的光合作用完全恢复。因此，光合诱导的稳定性可以成为未来作物育种中提高耐旱性的一个有希望的目标。
Drought stress is a major limiting factor for crop growth and yield. Water availability in the field can cyclically change between drought and rewatering conditions, depending on precipitation patterns. Concurrently, light intensity under field conditions can fluctuate, inducing dynamic photosynthesis and transpiration during the crop growth period. The present study aimed to characterize carbon gain and water use in fluctuating light under drought and rewatering conditions in two major crops, namely rice and soybean. We conducted gas exchange measurements under fluctuating light conditions with rice and soybean plants exposed to drought treatment (9–13 days) imposed by withholding water and subsequent rewatering treatment (8–9 days). Drought stress significantly reduced the maximum CO2assimilation rate (A) in soybean but not in rice. Under drought conditions,Aincreased after a step increase in light and then gradually decreased in both crops, resulting in the significant reduction of steady‐stateAin rice and soybean. Moreover, drought stress delayed photosynthetic induction in both crops even when it had relatively small impact on maximumA. These results suggest that the drought effects on photosynthesis should be evaluated based on induction, maximum, and steady states. The delayed photosynthetic induction under drought owing to the reduced gas diffusional conductance via stomata resulted in a substantial loss of leaf carbon gain under fluctuating light conditions. Meanwhile, rewatering, after drought, completely recovered photosynthesis under fluctuating light in both crops. Therefore, the stability of photosynthetic induction can be a promising target to improve drought tolerance during crop breeding in the future.