Abstract The search for more productive crops is exploring accessions with reduced chlorophyll accumulation in leaves, which would promote plant growth mainly because of a higher light transmittance throughout the canopy. Under continuous light, chlorophyll-depleted chlorina mutants of wheat can reach yields similar to WT; however, their performance under fluctuating light could possibly be lowered by a disturbed photosynthetic electron transport. Six chlorina mutants of Triticum aestivum (ANBW4A, ANBW4B, ANK32A) or T. durum (ANDW7A, ANDW7B, ANDW8A) were compared to WT genotypes under continuous and fluctuating light regimes, the latter obtained through a randomized pattern of light intensity changes. After two weeks of plant acclimation under either regimes, light energy management was thoroughly analysed for four weeks. All chlorina mutants showed a defective ability to regulate the electron poise during a fast rise in irradiance. Different extent of deregulation depended on mutation and genomic background, durum wheat being more severely impaired than bread wheat. However, a great acclimative capacity to a fluctuating light regime unexpectedly still characterized the chlorina wheat plants, with the only exception of the mutants carrying the cn-B1b mutated locus (ANDW7B and ANBW4B). Under fluctuating light, all other chlorina mutants developed indeed an ability to improve their control of electron transport against the recurrent reducing bursts caused by lightflecks. Compensatory responses included the regulation of energy distribution between photosystems, the use of alternative electron sinks, and a structural reorganization of the thylakoid system. However, in no case a reduced chlorophyll content led to more productive plants. Among 23 measured photosynthetic parameters, especially the non-regulatory energy dissipation in photosystem II - Y(NO) –, when probed during a light rise, can be proposed in automated phenotyping experiments as a straightforward index to be used for chlorina wheat screening with respect to potential productivity.

中文翻译：

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叶绿素耗尽的小麦突变体在光合电子流调节方面受到干扰，但可以保持对波动光环境的适应能力

摘要 寻找产量更高的作物正在探索叶片中叶绿素积累减少的种质，这将促进植物生长，主要是因为整个冠层的透光率更高。在连续光照下，小麦叶绿素耗尽的小叶突变体可以达到与WT相似的产量；然而，它们在波动光下的性能可能会因光合电子传输受到干扰而降低。将小麦（ANBW4A、ANBW4B、ANK32A）或硬粒小麦（ANDW7A、ANDW7B、ANDW8A）的六个小叶绿藻突变体与连续和波动光照条件下的 WT 基因型进行比较，后者通过光强度变化的随机模式获得。在任一方案下植物适应两周后，对光能管理进行了为期四个星期的彻底分析。所有 chlorina 突变体在辐照度快速上升期间都显示出调节电子平衡的能力有缺陷。不同程度的放松管制取决于突变和基因组背景，硬粒小麦比面包小麦受损更严重。然而，出乎意料的是，除了携带 cn-B1b 突变位点（ANDW7B 和 ANBW4B）的突变体之外，对波动光照条件的巨大适应能力仍然是 chlorina 小麦植物的特征。在波动的光线下，所有其他小绿藻突变体确实发展出了一种能力，可以改善它们对电子传输的控制，以对抗由光斑引起的反复减少爆发。补偿反应包括光系统之间能量分布的调节、替代电子汇的使用以及类囊体系统的结构重组。然而，在任何情况下，叶绿素含量的降低都不会导致植物的生产力更高。在 23 个测量的光合参数中，尤其是光系统 II 中的非调节性能量耗散 - Y(NO) -，当在光照上升期间进行探测时，可以在自动表型实验中提出，作为用于筛选 chlorina 小麦的直接指标到潜在生产力。