镉胁迫对续断菊Sonchus asper L.Hill.根系分泌物的影响

通过盆栽试验,研究了不同Cd质量分数（0、50、100、200 mg.kg-1）对续断菊Sonchus asper L.Hill.根系分泌总有机酸、游离氨基酸、可溶性糖的影响,旨在探明根系分泌物对续断菊超积累Cd的影响。结果表明：Cd胁迫下续断菊根系分泌总有机酸、游离氨基酸和可溶性糖的质量浓度显著增加,同时,总有机酸、可溶性糖和游离氨基酸又促进了植株对Cd的吸收。随着Cd处理质量分数的增加,续断菊地上部和根部镉质量分数显著增加,90 d时续断菊地上部镉质量分数与可溶性糖、游离氨基酸的质量浓度呈极显著正相关,相关系数分别为0.999（P〈0.01）和0.995（P〈0.01）,根部镉质量分数与可溶性糖、游离氨基酸的质量浓度也呈显著正相关,相关系数分别为0.998（P〈0.01）和0.987（P〈0.05）;Cd对续断菊根系可溶性糖的分泌、游离氨基酸的合成有刺激作用,根系分泌的可溶性糖和游离氨基酸可能在续断菊累积镉的过程中有重要作用。

Effects of Cd Contamination on the root exudates of Sonchus asper L. Hill.

Pot experiments was carried out to study the effects of four different cadmium levers（0,50,100,200 mg.kg-1） on the root exudates（total organic acids,amino acids and soluble sugar） of Sonchus asper L.Hill.in order to understand the relationship between root exudates and cadmium accumulation in Sonchus asper（L.） Hill.The results showed that with increasing concentration of cadmium,the contents of total organic acids,soluble sugar and dissociative amino acid of root exudates were increased significantly.In the meanwhile,the content of Cd in the shoot and root of Sonchus asper L.Hill was increased significantly,and Cd absorption of Sonchus asper L.Hill.was promoted with the increase of total organic acids,soluble sugar and dissociative amino acid of root exudates.In the 90 th d,there was a significantly positive correlation between shoot Cd contents and the contents of soluble sugar and dissociative amino acid,and the correlation coefficients are 0.999（P 0.01） and 0.995（P 0.01） respectively.There also was a significantly positive correlation between root Cd contents and the contents of soluble sugar and dissociative amino acid,and the correlation coefficients are 0.998（P 0.01） and 0.987（P 0.05） respectively.Soluble sugar and dissociative amino acid of root exudates might play an important role in cadmium accumulation of Sonchus asper（L.） Hill.