苹果树Zn含量的年变化及与根活力的关系

本试验以20年生‘红星/海棠’与盆栽‘辽伏/平邑甜茶’为试材,通过测定缺Zn病株与正常株的Zn含量及根活力,探讨了苹果树不同器官及根际土内Zn含量的年变化规律,分析了根含Zn量与根活力的关系。结果表明:(1)病叶的含Zn量显著低于正常叶,一年内正常叶Zn的含量有2次高峰,分别在春、秋梢生长的前期,而病叶只有1次,出现在春梢迅速生长期;病株根的含Zn量不低于正常株根。(2)在相同的立地条件下,缺Zn小叶病株与正常株的根系活力无显著差异。(3)根际土有效Zn含量充足时,苹果树根内含Zn量不完全决定于根系活力。

ANNUAL VARIATIONS OF ZINC CONTENT IN APPLE TREES AND ITS RELATION WITH ROOT VIGOUR

Two cultivars, the 20-yr-old'Starking' and'Liao Fu'apple trees, were used as material in the experiment. The content of zinc and root vigour of diseased and healthy plants were measured. The annual variations of zinc in different organs and rhizosphere soil were investigated. The relation between the content of zinc in roots and root vigour was also studied. The results were as follows: (1) The content of zinc in abnormal leaves was apparently less than that in normal ones. There were two times when much more zinc was measured in normal leaves, i.e. at the beginning of growth of spring and autumn shoots, but there was only one time for zinc to get peak level in abnormal ones, at the stage of rapid growth of spring shoots. The content of zinc in roots of diseased trees was no less than that in ones of normal trees. (2) Under the same soil conditions, there was no significant difference between the root vigour of diseased trees and that of normal trees. (3) Under conditions of sufficient content of available zinc in soil, the content of zinc in roots was not entirely dependent on the root vigour.