大白菜子叶光合功能及其对幼苗和产量的影响

大白菜绝非“基生叶展开以后才能开始完全依靠叶的光合作用独立生活…… ”。本试验确认子叶是第一个同化器官,它在大白菜的幼苗期起着一定作用。如在5叶期以前摘除子叶不仅对幼苗而且对叶球的重量(产量)也会有一定影响,愈是早期摘除子叶其影响愈大。

THE ROLE OF CHINESE CABBAGE COTYLEDONS IN PHOTOSYNTHESIS AND ITS EFFECT ON SEEDLING GROWTH AND HEADING YIELD

The cotyledons is the first photosynthetic organ of Chinese cabbage possessing a similar function with that of foliage leaves. The variations in net photosynthetic rate of the cotyledon are shown in table 2. The changing tendencies of net weight rate of photosynthesis represents increasing from the beginning of the cotyledons getting green color to 2 leaves period ( 8-days after emerging ) . The highest photosynthetic rate occurs between 2 leaves period. The growth of the whole plant either in seedling period or in heading period was severely affected evidently, while two cotyledons were removed ( defolicated ) at these periods. But the earlier the cotyledons were removed, the smaller the fresh weight of plant, the plant leaves area and the length of main root grew, as well as the lower the heading leaves number and the head weight got. The correspoundant results are shown in table 4 and 5.