Cr^（3＋）胁迫对青菜中植物络合素含量及AsA-GSH代谢关键酶活性的影响

采用不同浓度Cr3＋处理,测定不同耐铬性青菜品种叶片中抗坏血酸-谷胱甘肽（AsA-GSH）代谢关键酶活性及植物络合素含量等生理指标。结果表明,随着处理浓度的增加,两个青菜品种叶片中植物络合素及抗氧化剂含量呈增加趋势。高浓度Cr3＋（250mg·L-1）处理下,耐铬性强的矮抗青品种叶片中超氧阴离子（O-2·）含量与对照相比增幅较小,耐铬性差的绿秀品种则增幅较大;耐铬性强的矮抗青叶片中还原型抗坏血酸（AsA）、还原型谷胱甘肽（GSH）含量显著高于对照（P〈0.05）,而绿秀品种则略增,差异不显著（P〉0.05）;耐铬性强的矮抗青品种叶片中脱氢抗坏血酸（DHA）、氧化型谷胱甘肽（GSSG）含量分别是对照的1.87、1.72倍,低于耐性差的绿秀品种（1.98、1.94倍）。随着铬处理浓度的增加,AsA-GSH关键酶活性呈先增后降趋势。高浓度Cr3＋处理下,耐铬性强的矮抗青品种叶片中植物络合素（PCs）含量、抗坏血酸过氧化物酶（APX）及脱氢抗坏血酸还原酶（DHAR）活性分别比对照增加了30.9%、38.9%、45.2%,而耐性差的绿秀分别增加了11.5%、30.5%、43.0%。综合分析表明,矮抗青在Cr3＋处理下具有较高的AsA-GSH代谢关键酶活性和非酶物质含量,可能是不同青菜品种对Cr3＋耐受性差异的内在生理原因。

Effects of Chromium Stress on the Content of Phytochelatins and the Activities of Key Enzymes of Ascorbate- glutathione Cycle in Brassica chinensis L.

The content of phytochelatins and the activities of key enzymes of Ascorbate-glutathione cycle in wtrieties of Aikangqing and Lvx- iu were studied with different concentrations of Cr^3＋. The results showed that the contents of phytochelatins and antioxidant increased with the increase of Cr^3＋ concentration in both varieties.Under high concentration of Cr^3＋（250 gmg. L^-1 ）, O2- contents in leaves of cabbages were signifi- cantly increased （P〈0.05）, and the increased amount of Aikangqing was lower than that of Lvxiu. AsA and GSH contents in leaves of Aikangqing were significantly increased compared to control（P〈0.05 ）, while those of in Lvxiu were not significantly increased（P〉0.05 ）. DHA and GSSG contents in Aikangqing were 1.87 and 1.72 times as much as control and those were 1.98 and 1.94 times as much as control in Lvxiu, respectively. The activities of key enzymes in AsA-GSH increased with the increase of Cr^3＋ concentration. The content of phy- tochelatins （PCs）,the activity of ascorbte peroxidase （APX）, and dehydrateasorbate reductase （DHAR） in Aikangqing were 30.9%, 38.9%, 45.2% higher than control under the concentration of 250 mg.L^-1 Cr^3＋ treatment, respectively, while those in Lvxiu were 11.5%, 30.5%, 43.0% higher than control, respectively. In conclusion, Aikangqing had a higher activities of key enzymes of AsA-GSH and phytoehelatins under Cr^3＋ stress, which attribute to its higher Cr^3＋ tolerance. Our results showed that there were chromium-resistance differences between va- rieties of cabbages, this provides the theoretical guidance and technical support for people had the choice of 1,3w accumulation cabbages vari- eties.