苹果树叶片气孔活动的研究

A Study on Leaf Stomatic Activities of Apple Tree

用LI—1600型气孔计研究了苹果树叶片的气孔活动,结果表明:垂直叶片主脉中部的测量值可以代表叶片的平均值,几个枝中部叶片的平均气孔阻力可以代表该群体的气孔阻力;照光叶片的气孔阻力小于遮阴叶片的气孔阻力;嫩叶的气孔阻力小于成熟叶的气孔阻力。树冠平均气孔传导率与净辐射、气温及土壤含水率均有较密切的关系。有时苹果树的气孔传导率在中午有所下降,即“午休”现象。

A study on leaf stomatic activities of apple tree has been made by using LI-1600porometer. Resultes are presented as follows: the value measured at the middle part of the leaf at the right angles to main arter and veins can represent the average stomatic resistance of this leaf; The average stomatic resistance of some leaves in the middle parts of several branches can represent the average value of this colony; The stomatic reisstance of the sunlit leaf is less than the shaded leaf; The stomatic resistance of the tender leaf is less than the mature leaf. The average stomatic conductance of the canopy is closely related to net radiation, air temperature and soil water content. Decreasing of stomatic conductance, called 'noontime snooze', was found at noon during experimental course.