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

用10 ~ 10 μ M的Cd溶液培养耐重金属植物横隔沙芥（A. yokosense）和敏感植物桑、菜豆<-6><-3>3天，测定植物器官中重金属含量。在含有0.25M蔗糖的Tris HCl缓冲液（pH7.8）中研磨后，通过在200 xg、700 xg、10，000 xg下离心30分钟来分级分离各个器官。[结果]随着Cd浓度的升高，蹄盖蕨的养分吸收量没有迅速下降，而桑葚和大豆的养分吸收量则迅速下降。在低浓度Cd处理下，横隔蒿根系Cd含量低于桑葚和大豆。但在高浓度Cd处理下，植株间差异不明显，横蒿F1根系Cd含量超过90%，菜豆为55-70%，桑葚为30-50%。用茎尖培养法培育出二倍体、二倍体和四倍体植株，并在含5、10、15和20 μ M Cd的水溶液中培养。测定干重生长抑制系数。并通过上述方法进行分级。[结果]不同多倍体材料的耐药性存在差异，表现为二倍体&gt;二倍体&gt;四倍体。F_1代Cd含量表现为二倍体&gt;二倍体&gt;四倍体。这种秩序与宽容的秩序是一致的。

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.