几种作物叶片水势的初步研究

A PRELIMINARY STUDY ON THE LEAF WATER POTENTIAL CHANGES IN SOME CROPS

水稻、玉米和花生3种作物的叶片水势的日变化,都以黎明最高,上午较剧降低,午后13～14时最低,傍晚和晚上逐渐回升,黎明又出现最高值。水稻叶片水势日变化与温度日变化,呈极显著负相关。不同叶位的叶片水势,以最顶部展开叶最高,随着急剧下降,展开叶下一叶及下位叶的水势较低,变化与叶位次序无关。同一种作物,不同植株之间的叶片水势差异甚大。用水势仪(HR——33T DEW POINT MICROVOLTMETER)法和小液流法对5种植物叶片水势进行测定比较,结果基本一致。

The daily changes of water potential in three crops, rice, corn and peanut, were studied. Water potential was highest at dawn, dropping dramatially in the morning, and the lowest at 13- 14 P. M; it rose gradually at dusk and in the evening, and reached the highest again at next dawn. The daily changes in rice leaf water potential showed significant negative correlation with the daily changes of temperature. The leaf water potential varied with the leaf position, being highest in the topmost fully expanded leaves and then falling dramatically sequentially. The beaf water potentials were tower in the second from the fully expanded leaf and in the leaves further down, but there was no regular pattern between the leaf water potential and the leaf sequence. The leaf water potentials varied greatly among individual plants of a crop. The leaf water potentials ofthe five plant species were measured with a HR——33T DEW POINT MICROVOLTMETER and the method ofV. S. Chardakov (1953) and the results compared.