【摘要】 自然条件下水分状况对箭杆杨叶中输导组织及叶肉组织有一定的影响。水分状况好的叶中导管管腔直径大于水分状况差的，而管壁厚度却相反，水分状况差的导管管壁厚度大于水分状况好的。此点与试验条件下所得的结果略有差异，原因在于，试验条件下所用的材料为植物的幼茎或同化枝，而此项工作所用的材料为叶，在对干旱环境及水分状况变化的适应上，叶比茎或同化枝更为敏感。叶肉中栅栏组织在水分状况较差时发育程度比水分状况好时高。无论是导管管腔直径、管壁厚度还是栅栏组织，在５、７、９三个月内皆呈逐渐发达状态，显示了叶内组织的发育与成熟的过程。更多还原

【Abstract】 he result of this research shows that water can influence the conducting tis sue and the mesophyll tissue of the leaves of Populus nigra var thevestina in natural condi tion.When the water condition is good,the diameter of vessel is bigger but the thickness of the wall of vssel is smaller. In contrast,the diameter of vessel is smaller and the thickness of wall is bigger when the water condition is bad.This result is different from the result which we got under potted condition.The reason is the different meterials. In this research,the me terlal we used is leaves,the meterials we used under potted condition are branches and young stems.The leaves are more sensitive than branches and young stems to the change of water condition.The palisade tissue of mesophyll is more developed when the water condition is bad.The diamter of vessel,the thickness of the wall and the palisade tissue of mesophyll are all increase gradually from May to September.更多还原