Amitrano Chiara, Rouphael Youssef, De Pascale Stefania, De Micco Veronica
Department of Agricultural Sciences, University of Naples Federico II, 80055 Naples, Italy.
Plants (Basel). 2022 Sep 11;11(18):2369. doi: 10.3390/plants11182369.
The coordination of leaf hydraulic-related traits with leaf size is influenced by environmental conditions and especially by VPD. Water and gas flows are guided by leaf anatomical and physiological traits, whose plasticity is crucial for plants to face environmental changes. Only a few studies have analysed how variations in VPD levels influence stomatal and vein development and their correlation with leaf size, reporting contrasting results. Thus, we applied microscopy techniques to evaluate the effect of low and high VPDs on the development of stomata and veins, also analysing leaf functional traits. We hypothesized that leaves under high VPD with a modified balance between veins and stomata face higher transpiration. We also explored the variability of stomata and vein density across the leaf lamina. From the results, it was evident that under both VPDs, plants maintained a coordinated development of stomata and veins, with a higher density at low VPD. Moreover, more stomata but fewer veins developed in the parts of the lettuce head exposed to light, suggesting that their differentiation during leaf expansion is strictly dependent on the microclimatic conditions. Knowing the plasticity of hydraulic-related morpho-functional traits and its intra-leaf variability is timely for their impact on water and gas fluxes, thus helping to evaluate the impact of environmental-driven anatomical variations on productivity of natural ecosystems and crops, in a climate change scenario.
叶片水力相关性状与叶片大小的协调受到环境条件的影响，尤其是受蒸汽压亏缺（VPD）的影响。水分和气体流动受叶片解剖学和生理学性状的引导，这些性状的可塑性对于植物应对环境变化至关重要。只有少数研究分析了VPD水平的变化如何影响气孔和叶脉的发育及其与叶片大小的相关性，报告的结果相互矛盾。因此，我们应用显微镜技术来评估低VPD和高VPD对气孔和叶脉发育的影响，并分析叶片功能性状。我们假设，在高VPD条件下，叶脉和气孔之间平衡发生改变的叶片面临更高的蒸腾作用。我们还探究了整个叶片层面上气孔和叶脉密度的变异性。从结果来看，很明显在两种VPD条件下，植物都保持了气孔和叶脉的协调发育，在低VPD时密度更高。此外，生菜头部暴露于光照下的部分形成了更多的气孔但叶脉较少，这表明它们在叶片扩展过程中的分化严格依赖于微气候条件。了解水力相关形态功能性状的可塑性及其叶内变异性对于其对水分和气体通量的影响而言很及时，从而有助于在气候变化情景下评估环境驱动的解剖学变化对自然生态系统和作物生产力的影响。
