Pichaco Javier, Manandhar Anju, McAdam Scott A M
Irrigation and Crop Ecophysiology Group, Instituto de Recursos Naturales y Agrobiología de Sevilla (IRNAS, CSIC), Avenida Reina Mercedes 10, 41012 Seville, Spain.
Department of Botany and Plant Pathology, Purdue University, West Lafayette, IN 47907, USA.
Plant Physiol. 2024 Apr 30;195(1):370-377. doi: 10.1093/plphys/kiae023.
Stomatal opening in the light, observed in nearly all vascular land plants, is essential for providing access to atmospheric CO2 for photosynthesis. The speed of stomatal opening in the light is critical for maximizing carbon gain in environments in which light intensity changes, yet we have little understanding of how other environmental signals, particularly evaporative demand driven by vapor pressure deficit (VPD) influences the kinetics of this response. In angiosperms, and some fern species from the family Marsileaceae, a mechanical interaction between the guard cells and the epidermal cells determines the aperture of the pore. Here, we examine whether this mechanical interaction influences the speed of stomatal opening in the light. To test this, we investigated the speed of stomatal opening in response to light across a range of VPDs in seven plant species spanning the evolutionary diversity of guard cell and epidermal cell mechanical interactions. We found that stomatal opening speed is a function of evaporative demand in angiosperm species and Marsilea, which have guard cell and epidermal cell mechanical interactions. Stomatal opening speeds did not change across a range of VPD in species of gymnosperm and fern, which do not have guard cell mechanical interactions with the epidermis. We find that guard cell and epidermal cell mechanical interactions may play a key role in regulating stomatal responsiveness to light. These results provide valuable insight into the adaptive relevance of mechanical advantage.
在几乎所有维管陆地植物中观察到的气孔在光照下开放，对于光合作用获取大气中的二氧化碳至关重要。在光照强度变化的环境中，气孔在光照下开放的速度对于最大化碳获取至关重要，但我们对其他环境信号，特别是由蒸汽压亏缺（VPD）驱动的蒸发需求如何影响这种反应的动力学了解甚少。在被子植物以及一些来自苹科的蕨类物种中，保卫细胞与表皮细胞之间的机械相互作用决定了气孔的孔径。在这里，我们研究这种机械相互作用是否会影响气孔在光照下开放的速度。为了测试这一点，我们在跨越保卫细胞和表皮细胞机械相互作用进化多样性的七种植物物种中，研究了在一系列VPD条件下气孔对光照的开放速度。我们发现，气孔开放速度是具有保卫细胞和表皮细胞机械相互作用的被子植物物种和苹属植物中蒸发需求的函数。在裸子植物和蕨类植物物种中，气孔开放速度在一系列VPD范围内没有变化，这些物种的保卫细胞与表皮没有机械相互作用。我们发现，保卫细胞和表皮细胞的机械相互作用可能在调节气孔对光照的反应中起关键作用。这些结果为机械优势的适应性相关性提供了有价值的见解。
