硫缓解龙葵镉毒害效应的研究

采用水培试验，研究了不同浓度镉和硫交互处理下，龙葵（Solanum nigrum L.）生物量、镉含量、各器官非蛋白巯基含量的变化，以及镉在龙葵各器官的亚细胞分布情况。结果表明：（1）适量的硫可以增加龙葵的生物量；（2）龙葵地上部镉含量随着镉处理浓度的提高而降低，地下部镉含量则相反。同一浓度镉处理下，龙葵地上、地下部的镉含量都随着硫处理浓度的提高而呈现一定的下降趋势；（3）不同处理条件下，植物体内非蛋白巯基含量无显著差异；（4）镉主要集中在细胞壁而不是细胞器中。故推测，硫是通过阻止龙葵对镉的吸收而不是促进无毒化合物（Cd—S4-complex）的形成来缓解龙葵的镉毒害症状。

Alleviation of Cadmium Toxicity to Solanum nigrum L. by Sulfur

By water culture experiments with different concentrations of cadmium and sulfur,the biomass and cadmium content of Solanum nigrum L.were determined besides the non-protein thiol content and the subcellular distribution in different of organs.The results were as follows: ⑴ the biomass of Solanum nigrum L.could be raised by appropriate amount of sulfur under the same concentration of Cd stress;⑵ with the increasing of the cadmium concentration,the cadmium content decreased in shoots but increased in roots.Under the treatments with the same cadmium concentration,as the sulfur concentration increased,the cadmium content in both shoots and roots showed a certain trend of decrease;⑶ there was no significant difference of the non-protein thiol content among the different treatments;⑷ the cadmium mainly accumulated in cell wall but not in cell organelles.From all these results,one conclusion could be speculated that sulfur could alleviate the cadmium poisoning symptoms of Solanum nigrum L.by stopping the absorption of cadmium,but not by forming Cd-S4-complex.