镉胁迫对欧亚蔊菜克隆苗的萌发和生长的影响

Effects of Cadmium Stress on the Germination and Growth of Clonal Seedlings of Rorippa sylvestris

为了探究镉超富集植物的繁殖能力和群落的持久性,以欧亚蔊菜(Rorippa sylvestris)为试验材料,研究了其横走侧根克隆苗发生特点以及不同温度(15,20,25,30,35℃)和不同浓度(0,10,25,50,100,200μmol·L^(-1))的镉胁迫对克隆苗生长的影响。结果表明:欧亚蔊菜横走侧根发达,克隆能力极强;在15℃条件下克隆苗萌发数量很少,在25℃条件下克隆苗萌发数量最多,粗根、中根和细根萌发的克隆苗数分别为14.7,23.8,16.8个,当温度升高至35℃时,无克隆苗萌发;随着镉浓度的增加,克隆苗的数量表现出低促高抑的现象,当镉浓度为50μmol·L^(-1)时克隆苗萌发数量最多,粗根、中根和细根分别为23.5,23.8,16.8个,且细根的克隆苗萌发的数量始终低于粗根和中根。当镉浓度为25μmol·L^(-1)时克隆苗长度最长,粗根、中根和细根分别为4.94,4.94,4.11cm。与对照比,各个镉处理条件下丙二醛含量差异不显著(p>0.05);随着镉浓度的增加,脯氨酸含量逐渐增大,各处理间差异显著(p<0.05)。研究结果可为欧亚蔊菜应用于镉污染土壤的生态修复提供理论指导。

In order to explore the reproductive capacity and community persistence of cadmium hyperaccumulators, the occurrence characteristics of clonal seedlings on lateral roots and effects of temperature(15,20,25,30,35℃)and cadmium(0,10,25,50,100,200μmol·L^(-1))on the growth of clonal seedlings of Rorippa sylvestris were studied. The results showed that the lateral roots of Rorippa sylvestris were developed and the clone ability was strong. The number of clonal seedlings was smaller at 15℃, and was the largest at25℃, which was 14.7, 23.8 and 16.8 for large root, middle root and fine root, respectively. No clonal seedlings germinated when the temperature increased to 35℃. With the increase of cadmium stress concentration, the number of clonal seedlings showed a phenomenon of low promotion and high inhibition, when the cadmium concentration was 50μmol·L^(-1), the number of clonal seedlings of germination was the largest, which was 23.5, 23.8 and 16.8 for large root, middle root and fine root, respectively, and the number of clonal seedlings sprouting of fine root was always lower than that of large root and middle root. When the concentration of cadmium was 25μmol·L^(-1), the clonal seedlings reached the highest. Compared with the control, there was no significant difference in MDA content under different cadmium treatments(p>0.05). With the increase of cadmium concentration, free proline content increased gradually, and there were significant differences among treatments(p<0.05). This study will provide theoretical guidance for the ecological restoration of Rorippa sylvestris on Cd-contaminated soil.