Cd胁迫对续断菊Cd吸收分配及有机酸代谢的影响  

Effects of Cd stress on uptake and distribution of Cd and the low molecular weight organic acid metabolism in Sonchus asper L. Hill.

作　　者：秦丽[1] 何永美[1] 李元[1] 李博[1] 祖艳群[1] 

机构地区：[1]云南农业大学资源与环境学院,昆明650201

出　　处：《环境化学》2016年第8期1592-1600,共9页Environmental Chemistry

基　　金：国家自然科学基金云南联合项目(U1202236)和国家自然科学基金(31560163)资助~~

摘　　要：通过水培试验,研究了Cd在续断菊(Sonchus asper L.Hill.)体内的亚细胞分布、化学形态,Cd对续断菊地上部和根部有机酸含量的影响,以及根系分泌低分子有机酸对Cd胁迫的响应.结果表明:(1)续断菊根部和地上部的Cd含量随Cd处理浓度增加而显著增加;(2)Cd在续断菊体内的化学提取形态分布为:NaCl提取态(F_(NaCl))>HAC提取态(F_(HAC))>HCl提取态(F_(HCl))>残渣态(FR)>去离子水提取态(FW)>乙醇提取态(FE);(3)续断菊体内的Cd主要分布在细胞壁中,占总Cd含量的36%—47%,且随着Cd浓度的升高,细胞壁中的分布量增加;其次是细胞核中,占总含量的20%—33%;(4)续断菊体内低分子有机酸含量大小为:酒石酸>苹果酸>柠檬酸>乙酸,酒石酸占有机酸总量的68%—96%,植株地上部和根部Cd含量均与体内苹果酸和柠檬酸含量显著正相关,相关系数为0.993和0.994(P<0.01)、0.953和0.982(P<0.05);(5)不同Cd浓度下,续断菊根系分泌低分子有机酸主要为酒石酸,占有机酸总量的52%—89%,且在30 d时与植株地上部和根部Cd含量显著正相关,相关系数为0.967和0.978(P<0.05).根系分泌酒石酸和苹果酸促进了续断菊对Cd的吸收,续断菊体内的苹果酸和柠檬酸参与Cd的吸收、运输、积累,从而缓解了Cd的危害;同时,细胞壁固持和活性较强化学形态的减少是续断菊耐Cd胁迫的主要机制.A hydroponic experiment was applied to explore the subcellular distribution and chemical forms of Cd in hyperaccumulator Sonchus asper L. Hill. （S. asper）, the effects of Cd on the contents of organic acids in shoots and roots, and the response of root exudates to Cd tolerance. The results showed that Cd contents in the shoot and root of S. asper increased with the increase of Cd concentrations in solution. The contents of Cd chemical forms upon Cd addition followed the order of NaC1 extractable fraction （ FNaCl ） 〉 HAC extractable fraction （ FHAC ） 〉 HC1 extractable fraction （ FHCl ） 〉 residual fraction（ FR ） 〉water extractable fraction （ Fw ） 〉 ethanol-extractable fraction （ FE ）. 36%-47% and 20%-33% of total Cd distributed in cell wall and nucleus, respectively. The subcellular distribution of Cd was mainly in cell wall and the percentage of Cd in cell wall increased with the increase of Cd concentration. The contents of organic acids in S. asper followed the tendency of tartaric acid〉 malic acid 〉citric acid 〉 acetic acid. Tartaric acid was dominant, accounting for 68%-96% of total organic acids. Significandy positive correlations between shoot Cd and malic acid and citric acid were observed with correlation coefficients 0.993 （P〈0.01） and 0.953 （P〈0.05）, and significantly positive correlations between root Cd and malic acid and citric acid were observed with correlation coefficients 0. 994 （ P 〈 0.01 ） and 0. 982 （ P 〈 0.05 ）, respectively. With Cd concentrations in solution, low molecular weight organic acids of root exudates were mainly tartaric acid, which accounted for 52%-89%. Significantly positive correlation was observed between shoot Cd and root Cd with tartaric acid contents, and the correlation coefficient was 0.967 （P〈0.05） and 0.978 （P〈0.05）, respectively. The results indicate that tartaric acid and malic acid in root exudates of S. asper facilitated the absorption and accumulation of Cd, and malic acid and citric ac

关 键 词：CD 续断菊 亚细胞分布 化学形态 低分子有机酸 

分 类 号：X173[环境科学与工程—环境科学]