镉胁迫下柠条锦鸡儿种子萌发及幼苗生长的抗性分析

Resistance of Caragana Korshinskii Kom to Cd^(2+) Stress on Seeds Germination and Seedling Growth

采用滤纸-Hoagland营养液培养法研究了种子萌发和幼苗生长期的柠条锦鸡儿对高浓度重金属Cd2+的抗性表现,分析了幼苗叶片中丙二醛、可溶性蛋白和脯氨酸3个抗性生理生化指标的响应变化.结果表明:Cd2+≤300mg/L时,柠条锦鸡儿的种子发芽率66.7%、幼苗成活率63%,和对照(无Cd2+胁迫)相比,其根和茎受抑制程度较轻、生物量无显著下降,表现出良好的抗性和耐受性;Cd2+浓度在400mg/L^500mg/L时,种子发芽率40%、幼苗成活率低于50%,幼苗生物量下降了33%,Cd2+毒害率高达44%,对种子萌发和幼苗生长的抑制非常显著.幼苗叶片中丙二醛、脯氨酸和可溶性蛋白等抗性生理指标变化趋势表明在Cd2+浓度≥300mg/L时对柠条细胞质膜、蛋白质合成造成较大毒害,导致抗性的急剧降低.

The resistance of Caragana korshinskii Kom to high concentration of Cd^2＋during seeds germination and seedling growth was studied by using filter paper-Hoagland nutrient solution method.The response changes of three physiological and biochemical resistance indexes（malondialdehyde,soluble protein and proline）in seedling leaves were analyzed.Under lower concentration of Cd2＋（≤300 mg/L）,the germination rate of the seeds of Caragana korshinskii Kom was 66.7%,and the seedling survival rate was63%.Compared with the control（no cadmium stress）,the inhibited degree of roots and stems was lighter,and the biomass did not decrease significantly,showing good resistance and tolerance.Under higher concentration of Cd^2＋（400-500 mg/L）,the germination rate was 40%,seedling survival rate was under50%,and biomass of seedlings reduced by 33%,and the toxicity reached to 44%,showing significant inhibition of seeds germination and seedling growth.The changes of physiological resistance indexes indicate that cell plasmalemma and protein synthesis will be damaged seriously when the Cd^2＋concentration is above 300 mg/L,which will lead to sharp decrease of resistance.