Xiong Dongliang, Flexas Jaume
National Key Laboratory of Crop Genetic Improvement, MOA Key Laboratory of Crop Ecophysiology and Farming System in the Middle Reaches of the Yangtze River, College of Plant Science and Technology, Huazhong Agricultural University, Wuhan, Hubei, 430070, China.
Research Group on Plant Biology under Mediterranean Conditions, Universitat de les Illes Balears/Instituto de Investigaciones Agroambientales y de Economía del Agua (INAGEA), Carretera de Valldemossa Km 7.5, Palma de Mallorca, Illes Balears, 07121, Spain.
New Phytol. 2020 Dec;228(6):1754-1766. doi: 10.1111/nph.16801. Epub 2020 Aug 28.
The functions of stomata have been studied for a long time; however, a clear understanding of the influences of stomatal distribution on photosynthesis, especially the CO diffusion, is still unclear. Here, we investigated the stomatal morphology, distribution on leaf surfaces, vein traits and gas exchange parameters of 61 species, of which 29 were amphistomatous, spanning 32 families. Photosynthesis (A) was tightly coupled with operational stomatal conductance (g ) and mesophyll conductance (g ) regardless of whether phylogenetic relationships were accounted for. Although the enhancement of g from ferns and gymnosperms to angiosperms could largely be explained by the increase in leaf vein density (VLA) and stomatal density (SD), the g was decoupled from VLA and SD across angiosperm species. Instead, A in angiosperms was further influenced by the allocation of stomatal pores on leaf surfaces, which dramatically increased g and g . Moreover, the ratio of g to anatomically based maximum g was, on average, 0.12 across species. Our results show that the shift of stomatal pores from one leaf side to both sides played an important role in regulating CO diffusion via both stomata and mesophyll tissues. Modifications of stomata distribution have potential as a functional trait for photosynthesis improvement.
气孔的功能已经被研究了很长时间；然而，对于气孔分布对光合作用，尤其是二氧化碳扩散的影响，仍缺乏清晰的认识。在此，我们研究了61种植物的气孔形态、叶片表面分布、叶脉特征和气体交换参数，其中29种为双面气孔植物，涵盖32个科。无论是否考虑系统发育关系，光合作用（A）都与有效气孔导度（g）和叶肉导度（g）紧密相关。尽管从蕨类植物、裸子植物到被子植物，g的增加在很大程度上可以由叶脉密度（VLA）和气孔密度（SD）的增加来解释，但在被子植物物种中，g与VLA和SD解耦。相反，被子植物中的A进一步受到叶片表面气孔孔隙分配的影响，这显著增加了g和g。此外， across species（此处across species表述似乎有误，可能影响理解，暂按原文），g与基于解剖学的最大g的比值平均为0.12。我们的结果表明，气孔孔隙从叶片一侧转移到两侧在通过气孔和叶肉组织调节二氧化碳扩散方面发挥了重要作用。气孔分布的改变作为提高光合作用的功能性状具有潜力。
