Alleviation of Calcium on Toxicity of Cadmium to Rice Seedlings by Inhibiting Cadmium Accumulation and Relieving Oxidative Damage

【摘要】 Accumulation characteristics and antioxidant enzyme activities in rice seedlings from a high-cadmium（Cd）-accumulating cultivar Tyou705（705）and low-Cd-accumulating cultivar Xiangzao 24（X24）were studied,based on hydroponic experiment.Three levels of calcium（Ca）(0,1.0 and 2.0 mmol·L^-1)and two levels of Cd(0 and 2.7μmol·L^-1)were designed in this study.Experimental results showed that the tolerance of rice seedlings to Cd stress was significantly improved by adding 1.0 or 2.0 mmol·L^-1Ca.Comparing with Cd control,adding 1.0 mmol·L^-1 Ca made the seedling biomass of 705 and X24 increased by 68.9%and116.2%,respectively.Addition of 2.0 mmol·L^-1 Ca was more effective than that of 1.0 mmol·L^-1 Ca in promoting rice biomass,root tip number,total root length,and total root surface area.After addition of 2.0 mmol·L^-1 Ca and Cd contents in roots and shoots of 705 decreased by 23.5%and 35.2%,Cd in roots and shoots of X24 decreased by 22.2%and 18.7%,respectively.Addition of Ca significantly promoted the accumulation of Mg,K and Zn in shoots and roots of X24 under Cd stress environment and eliminated the inhibitory effect of Cd on the uptake of these elements.Both 1.0 and 2.0 mmol·L^-1 Ca significantly decreased the activities of superoxide dismutase（SOD）and peroxidase（POD）in rice seedlings under Cd stress.These results indicated that 1.0-2.0 mmol·L^-1 Ca could significantly reduce Cd content in rice roots and shoots,promote the uptake and accumulation of essential elements and alleviate the oxidative damage caused by Cd stress in rice seedlings.更多还原

【Abstract】 Accumulation characteristics and antioxidant enzyme activities in rice seedlings from a high-cadmium（Cd）-accumulating cultivar Tyou705（705）and low-Cd-accumulating cultivar Xiangzao 24（X24）were studied,based on hydroponic experiment.Three levels of calcium（Ca）(0,1.0 and 2.0 mmol·L^-1)and two levels of Cd(0 and 2.7μmol·L^-1)were designed in this study.Experimental results showed that the tolerance of rice seedlings to Cd stress was significantly improved by adding 1.0 or 2.0 mmol·L^-1Ca.Comparing with Cd control,adding 1.0 mmol·L^-1 Ca made the seedling biomass of 705 and X24 increased by 68.9%and116.2%,respectively.Addition of 2.0 mmol·L^-1 Ca was more effective than that of 1.0 mmol·L^-1 Ca in promoting rice biomass,root tip number,total root length,and total root surface area.After addition of 2.0 mmol·L^-1 Ca and Cd contents in roots and shoots of 705 decreased by 23.5%and 35.2%,Cd in roots and shoots of X24 decreased by 22.2%and 18.7%,respectively.Addition of Ca significantly promoted the accumulation of Mg,K and Zn in shoots and roots of X24 under Cd stress environment and eliminated the inhibitory effect of Cd on the uptake of these elements.Both 1.0 and 2.0 mmol·L^-1 Ca significantly decreased the activities of superoxide dismutase（SOD）and peroxidase（POD）in rice seedlings under Cd stress.These results indicated that 1.0-2.0 mmol·L^-1 Ca could significantly reduce Cd content in rice roots and shoots,promote the uptake and accumulation of essential elements and alleviate the oxidative damage caused by Cd stress in rice seedlings.更多还原