Studies on gas transport system in plants.

用扫描显微镜对莲叶片中央板的形态进行了观察。中央板表面有类似气孔的结构。叶片上的气孔器比气孔器大2倍左右，分布密度约为气孔器的1/4。在装置中观察到了保卫细胞结构。在器官下方有一个腔隙，与叶片上的大腔隙相连。在白天，仪器中的守卫状细胞之间的间隙大多非常狭窄或封闭，另一方面，大多数间隙在夜间是大而开放的。实验结果表明，该装置主要负责控制空隙内的气体压力，空隙内的压力主要是由空隙与大气之间的温度和湿度差异驱动的热渗透和湿度增压的物理效应产生的。穴腔内压力的增加可能最有利于氧气通过扩散向根系的运输。相反，较高的压力会导致通气组织中通气速率的降低，从而降低根系呼吸所需的氧浓度。已知加压与通气组织的渗漏呈负相关。

The morphological observation of central plate of leaf blade of Nelumbo nucifera was conducted with a scanning microscope. The apparatus similar to stoma was found on the surface of the central plate. The size of the apparatus was around 2 limes larger than stoma found on the leaf blade, and the distribution density was one fourth of that of leaf stoma. There observed the guard-like cell structure in the apparatus. There found lacuna just under the apparatus, which was connected to large lacunae running in leaf blade. The most of the gaps between the guard-like cells in the apparatus were very narrow or closed in the daytime, on the other hand the most of the gaps were large and open in the nighttime. It was suggested that the apparatus is responsible for controlling the gas pressure in lacunae, where pressure was generated by physical effects of thermo-osmosis and hygrometric pressurization driven by the differences of temperature and humidity between lacunae and atmosphere mostly occurred in daytime. The increase of pressure in the lacunae may be most beneficial for transport of oxygen to roots by diffusion. The higher pressure, on the contrary, leads to the decrease of ventilation rate in aerenchyma, then concentration of oxygen available for root respiration may be lowered. The pressurization is known to be negatively correlated with leakiness of aerenchyma.