短期低温下稀土对麻楝幼苗生理指标的影响

Effects of Rare Earth on Physiological Indices of Chukrasia tabularis Seedlings Under Short-Time Low Temperature

用500和1 000 mg.L-1稀土溶液喷施麻楝Chukrasia tabularis幼苗,置于3℃低温下3和7 d后,对其生理指标进行了测定.结果表明：2种质量浓度稀土处理的麻楝幼苗叶片的相对电导率,低温处理3 d后分别比对照显著增加9%和14%,低温处理7 d后分别比对照下降4%和11%.2种质量浓度稀土处理的脯氨酸和可溶性蛋白质含量在低温处理3和7 d后增加.低温处理3 d后,500 mg.L-1稀土处理的幼苗叶片中叶绿素含量比对照和1 000mg.L-1处理的均显著减少13%,低温处理7 d后,2种质量浓度稀土处理分别比对照显著增加11%和17%.稀土处理的幼苗叶片SOD活性在低温处理3 d后与对照接近或大于对照,低温处理7 d后比对照显著增加8%~11%.低温处理3 d后,500 mg.L-1稀土处理的丙二醛（MDA）含量比对照增加了8%,而1 000 mg.L-1稀土处理和低温7 d后的2种质量浓度稀土处理比对照减少了7%~11%.可见,500 mg.L-1稀土处理的幼苗经历低温7 d后以及1 000 mg.L-1稀土处理的幼苗经历3和7 d后均提高了抗寒性.

Chukrasia tabularis seedlings were laid on low temperature of 3 ℃for three and seven day after they were sprayed with rare earth of 500 and 1 000 mg·L-1,respectively,and then their physiological indices were determined.The results showed that,as compared with the control,the relative electrical conductivity of the seedlings sprayed with rare earth of two mass concentrations significantly increased by 9% and 14%,respectively,under three-day low temperature,whereas that of the seedlings decreased by 4% and 11%,respectively,under seven-day low temperature.The contents of free praline and soluble protein increased after three-and seven-day low temperature.Under three-day low temperature,the chlorophyll content of seedlings sprayed with rare earth of 500 mg·L-1 significantly decreased by 13% as compared with the control and seedlings sprayed with rare earth of 1 000 mg·L-1,whereas under seven-day low temperature,that of the seedlings sprayed with rare earth of two mass concentrations significantly increased from 11% to 17%.The SOD activity of seedlings sustaining three-day low temperature was greater than the control or close to the latter.Under seven-day low temperature,the SOD activity of seedlings sprayed with rare earth of two mass concentrations significantly increased from 8% to 11%,as compared with the control.Under three-day low temperature,the MDA content of seedlings sprayed with rare earth of 500 mg·L-1 increased by 8%,whereas that of seedlings sprayed with rare earth of 1 000 mg·L-1 and those under seven-day low temperature decreased from 7% to 11% compared with the control.In this study,seedlings sprayed with rare earth of 500 mg·L-1 after seven-day low temperature and sprayed with rare earth of 1 000 mg·L-1 after three-and seven-day improved their cold resistance ability.