Trade-off between grain yield and protein concentration is modulated by canopy photosynthesis in Japanese wheat cultivars
Trade-off between grain yield and protein concentration is modulated by canopy photosynthesis in Japanese wheat cultivars
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日本小麦品种的冠层光合作用调节谷物产量和蛋白质浓度之间的权衡
DOI：
10.1101/2022.08.17.502868
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Ikawa Hiroki
中科院分区：
文献类型：
--
作者：
Murakami Keach;Ikawa Hiroki
谷物产量和蛋白质浓度之间的负相关阻碍了有效的养分供应。为了分析这种相反关系的原因，我们比较了两个日本小麦品种的叶片和冠层光合作用。叶片气体交换测定表明，高产低蛋白品种‘Kitahonami’从开花前到灌浆后期一直保持较高的气孔导度，而低产高蛋白品种‘Yumechikara’白天气孔关闭，导致光合作用下降。我们用一个模型模拟了冠层光合作用，并量化了不同的气孔行为对冠层碳增益的贡献。虽然当使用上午获得的模型参数时，‘Yumechikara’的冠层每日光合作用增益与之相当或略低，但当使用中午参数时，‘Yumechikara’的光合作用增益显著低于‘Kitahonami’。在灌浆中期，‘Yumechikara’的冠层呼吸损失大于‘Kitahonami’，这是因为‘Yumechikara’的冠层含氮量较高，导致两个品种的冠层净碳增量存在较大差异。我们的研究表明，高蛋白品种获得较低碳增量的途径之一，较高的氮含量并不一定会导致较大的碳增量。
A negative correlation between grain yield and protein concentration hinders an efficient nutrient supply. To analyze the causation of this inverse relationship, we compared the leaf and canopy photosynthesis of two Japanese wheat cultivars. Gas exchange measurements of leaves revealed that ‘Kitahonami’ (a high-yielding and low-protein cultivar) maintained high stomatal conductance from pre-anthesis to late grain-filling stage while stomata of ‘Yumechikara’ (a low-yielding and high-protein cultivar) were closed during the daytime, leading to decreased photosynthesis. We simulated canopy photosynthesis using a model and quantified the contribution of distinct stomatal behavior to canopy carbon gain. Although daily canopy photosynthetic gain was comparable or slightly low in ‘Yumechikara’ when model parameters obtained in the morning were used, the gain was substantially lower in ‘Yumechikara’ than in ‘Kitahonami’ when midday parameters were used. Canopy respiratory loss in ‘Yumechikara’ was greater than that in ‘Kitahonami’ during the middle of the grain-filling period because of its high canopy nitrogen content, leading to a considerable difference in net canopy carbon gain between the cultivars. Our study suggests one of the pathways for a lower carbon gain of a high protein cultivar and the greater nitrogen content does not necessarily result in a greater carbon gain.