The impact of slow stomatal kinetics on photosynthesis and water use efficiency under fluctuating light.
The impact of slow stomatal kinetics on photosynthesis and water use efficiency under fluctuating light.
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DOI：
10.1093/plphys/kiab114
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发表时间：
2021-06-11
期刊：
影响因子：
7.4
通讯作者：
Carpentier S
中科院分区：
文献类型：
--
作者：
Eyland D;van Wesemael J;Lawson T;Carpentier S
香蕉全株蒸腾速率证实了叶片水平气孔动力学，但波动光下气孔动力学的影响取决于其他因素，如一天中的时间。动态光照条件要求持续调节气孔开度。气孔导度(GS)动力学被认为是植物生产力和水分利用效率(WUE)的关键。利用光强阶跃变化的方法，研究了5个香蕉品种(Musa spp.)并模拟了扩散限制和生物化学限制对光合作用的影响(A)。主要的A限制因素是与GS动力学有关的扩散限制。GS对所有品种的A均有较强的限制作用，表现出优先节水的特点。此外，还观察到A的GS动力学和GS极限存在显著的基因型差异。对于两个不同的基因型，在现实的日波动光照条件下和在全株水平上，进一步研究了差异GS动力学的影响。叶片水平上观察到的气孔动力学在全株水平上被蒸腾动力学所证实，证实了尽管叶片不同部位和不同叶片间GS控制不同，但仍保持了对基因型的响应。然而，在昼夜变化的光照条件下，GS速度对A和内禀(IWUE)的影响依赖于一天中的不同时间。在下午，动力学上出现了一个挫折：绝对GS和GS对光的反应被抑制，强烈地限制了A，并影响了白天的iWUE。我们得出结论，差异GS动力学的影响依赖于目标光强度、变化的幅度、在光强度变化之前的GS，特别是一天中的时间。
Whole-plant transpiration rapidity corroborated leaf-level stomatal kinetics in banana, but impacts of stomatal dynamics under fluctuating light depended on other factors like time of day. Dynamic light conditions require continuous adjustments of stomatal aperture. The kinetics of stomatal conductance (gs) is hypothesized to be key to plant productivity and water use efficiency (WUE). Using step-changes in light intensity, we studied the diversity of light-induced gs kinetics in relation to stomatal anatomy in five banana genotypes (Musa spp.) and modeled the impact of both diffusional and biochemical limitations on photosynthesis (A). The dominant A limiting factor was the diffusional limitation associated with gs kinetics. All genotypes exhibited a strong limitation of A by gs, indicating a priority for water saving. Moreover, significant genotypic differences in gs kinetics and gs limitations of A were observed. For two contrasting genotypes, the impact of differential gs kinetics was further investigated under realistic diurnally fluctuating light conditions and at the whole-plant level. Genotype-specific stomatal kinetics observed at the leaf level was corroborated at whole-plant level by transpiration dynamics, validating that genotype-specific responses are still maintained despite differences in gs control at different locations in the leaf and across leaves. However, under diurnally fluctuating light conditions the impact of gs speediness on A and intrinsic (iWUE) depended on time of day. During the afternoon there was a setback in kinetics: absolute gs and gs responses to light were damped, strongly limiting A and impacting diurnal iWUE. We conclude the impact of differential gs kinetics depended on target light intensity, magnitude of change, gs prior to the change in light intensity, and particularly time of day.