Cd2＋对狗牙根、假俭草种子萌发及幼苗生长的影响

摘要

探讨了Cd2＋浓度对狗牙根与假俭草种子萌发和幼苗生长的影响。结果表明，两草种种子的发芽势、发芽率、发芽指数、活力指数、根长以及幼苗长度均随Cd2＋浓度的升高而降低；叶片叶绿素含量随Cd2＋浓度的升高略有降低；叶片丙二醛（MDA）含量随Cd2＋浓度的升高呈先降后升趋势；狗牙根过氧化氢酶（CAT）活性随Cd2＋浓度升高呈先升高后降低趋势，在5．0 mg／L时显著高于CK，假俭草各处理浓度的CAT活性均低于CK；两草种的过氧化物酶（POD）活性随Cd2＋浓度的升高呈先升高后降低趋势，并在10．0 mg／L 时达到峰值；Cd2＋浓度在5．0，10．0，20．0，40．0 mg／L时，狗牙根和假俭草多酚氧化酶（PPO）活性均高于CK，两草种PPO 活性随Cd2＋浓度的升高都呈先升高后降低趋势。两草种对 Cd2＋均有一定的耐受能力，狗牙根耐受能力大于假俭草，二者均可以应用于Cd2＋轻度污染土壤。%The effect of Cd2+ concentration on the germination and growth of Cynodondactylon and Eremochloa ophiuroides has been studied.The results showed that the seed germination rate,germination vigor,germina-tion index,vigor index,root length and seedling length of the two turfgrass species decreased with increases in Cd2+ concentration.Chlorophyll content in leaves decreased slightly and the MDA contents in leaves showed a rising trend after an initial drop with increasing Cd2+ concentration.The CAT activities of C. dactylon in-creased at first and then decreased with increasing concentrations.At a Cd2+ concentration of 5 .0 mg/L,CAT activities were significantly higher than that of CK,while the CAT activities of E. ophiuroides in all treat-ments were lower than that of CK.The POD activities of the two turfgrass species increased at first and then decreased with increasing Cd2+ concentration,reaching its peak at 10.0 mg/L.The PPO activities of C. dac-tylon and E. ophiuroides were higher than CK when the concentrations were at 5.0,10.0,20.0 and 40.0 mg/L.With increasing Cd2+ concentrations,the PPO activities of both species showed a declining trend follow-ing an initial rise.The two turfgrass species have a certain degree tolerance of Cd2+,with the tolerance of C. dactylon greater than that of E. ophiuroides.Both turfgrass species can thus be used in soils with low levels of Cd2+ pollution.