MECHANISM OF HEAVY METAL TOLERANCE IN FEW PLANTS,MULBERRY DND OTHERS

在含Cd浓度为10℃~(-6)~(-6)~(-3)~(-3)M的Cd水溶液中，对耐重金属的植物、敏感植物桑树和菜豆进行培养3d，测定植物各器官中的重金属含量。各器官在含0.25M蔗糖的Tris HCl缓冲液(pH7.8)中研磨后，分别以200xg、700xg、10000xg的浓度离心30min。[结果]随着Cd浓度的升高，蹄盖蕨属植物的养分吸收没有迅速下降，但桑树和大豆的养分吸收迅速下降。杨梅根系中Cd含量低于低浓度Cd处理的桑树和大豆。但在较高Cd浓度处理下，植株间差异不明显，黄豆根系Cd占总Cd的90%以上，菜豆为55~70%，桑树为30~50%。通过对单倍体、二倍体和四倍体植株进行茎尖培养，并在含Cd 5，10，15和20muM的水溶液中培养，结果表明，耐Cd植株首先被细胞壁捕获，Cd的抑制作用减弱。测定干重生长的抑制系数。[结果]观察到多倍体之间的耐性差异，单倍体、二倍体和四倍体。F1组分中Cd含量为单倍体、二倍体和四倍体。这个命令与宽容的命令是一致的。

Heavy metal tolerant plant, Athyrium yokoscense and sensitive plants, mulbeey and kidneybean were cultivated in water solution containing Cd at 10^<-6>-10^<-3>M for 3 days and heavy metal contents in plant organs were measured. And individual organs were fractioned by centrifuged at 200xg, 700xg, 10,000xg for 30min after grind in Tris HCl buffer (pH7.8) containing 0.25M succrose.[result] Nutrient uptake did not fall rapidly as the ascent of Cd concentration in Athyyrium yokoscense, but it fell rapidly in mulberry and soybean. Cd content in roots in A.Yokoscense was lower than that in mulberry and soybean treated with lower concentration of Cd. But the difference among plants was not observed treated with higher Cd concentration.Cd in the F1 raction of roots was more than 90% of the whole in A.yokoscence but 55-70% in kidneybean and 30-50% in mulberry. It was considered that Cd was catched by cell wall at first in the tolerant plant and the inhibition by Cd was weakened.Monoploid, dipoid and tetraploid plants were grown by the culure of shoot apex and cultiivated in water solutions containing 5,10,15 and 20muM Cd. Inhibition cofficient of dry weight growth was measured. And fractination was performed by the method as above-mentioned.[result] Differnce of tolerance among pollyploids were observed, monoploid>dipolid>tetraploid. Cd content in the F1 fraction was monoploid>dipolid>tetraploid. This order agreed with that of tolerance.