三种测定植物叶水势方法的比较

染色法测定玉米叶水势,样品在溶液中不需浸泡30min。压力室和热电偶测定小麦、玉米叶水势值基本一致;但测定棉花、杨树叶水势差异较大。染色法测定玉米叶水势,在高水势时其值比热电偶低,低水势下比热电偶高。虽然三种方法测定值不完全相同,但均随叶片脱水而变化。因此可用它们测定不同条件下叶片水势值的相对变化。

COMPARISONS OF THREE METHODS FOR DETERMING WATER POTENTIAL IN PLANT LEAVES

When the dye method is used to determine water potential of corn leaves , it is not necessary to immerse corn leaf samples into the test solution for 30 min. When the pressure chamber a'nd the thermocouple psychrometer are used to determine water potential of wheat and corn leaves, the values of water potential are basically in agreement, but when they are used to determine water potential of cotton and popular leaves, the values of wheat potential are greatly different, when the dye method is used to determine water potential of corn leaves, its values are lower in the case of high water potential and higher in the case of low water potential than those determined by the thermocouple psychrometer. Alt-bough the values determined by three methods are not entirely the same, they vary with the leaf dehydration. Therefore, these methods can be used to determine the relative variations of values of leaf water potential under different conditions.