镉对小麦幼苗的生长和生理生化反应的影响

镉对小麦幼苗和根系生长有抑制作用,尤以对根系的抑制更为显著,但镉浓度为5ppm时,有刺激生长的作用.幼苗的脯氨酸和可溶性蛋白质含量随镉浓度的增加而增加,尤其在高浓度镉下脯氨酸含量剧增,电解质外渗率也明显增大.镉使胚乳中的α-淀粉酶活性降低,这种效应随镉浓度增高而加强,随幼苗的生长却趋于减弱.镉诱导根的正、负极向过氧化物酶同工酶产生新谱带,并使原有的一些谱带活性增强.上述结果显示出镉使小麦幼苗的细胞结构和功能受到损害,而小麦幼苗对镉害也表现出一定的适应性保护反应.

Effects of Cadmium on the Growth and Physiological and Biochemical Reactions of Wheat Seedlings

With the content of Cd2+ of 0 , 5 , 10, 20, 50 and 100 ppm, we grew wheat seedlings in knop nutritive solutions to study their effects on the growth and physiological functions of the wheat seedlings. And we found the effects. Under cadmium stress, both the growth of wheat seedlings and its roots were inhibited, and the inhibitions to the latter were more obvious; but 5 ppm-concentration cadmium could simulate the growth of wheat seedlings (Fig. 1 ) .As the cadmium concentration increased, the proline and soluble protein contents in wheat seedlings also increased, and the proline contents would increase a lot with high cadmium concentration (Fig. 2 ) . With high cadmium concentration, the electrolyte leakage increased obviously (Fig. 3 ) , and this showed that cadmium could injure membrane. Cadmium could inhibite the activities of ?-amylase in endosperm, which intensified as the cadmium concentration increased, and which tended to abate as the wheat seedlings were growing (Fig. 3 ) . Cadmium could induce the anode and cathode peroxidase isoenzyme bands of the roots new enzymatic bands,and also could intensify the activities of some original enzymatic bands (Fig. 4 , Fig. 5). All these indicated that the effects of cadmium on the shape and physiological and biochemical functions of wheat seedlings has some relationship with cadmium concentration. Meanwhile, it showed that cadmium could do harm to the structure and functions of the cells in the wheat seedlings. The wheat seedlings had some adaptable protection to cadmium calamities.