氯化镧对铝胁迫下大豆幼苗抗氧化能力及光合性能的影响

Effects of LaCl_3 on the Photo-synthesis and Anti-oxidant Capacity of Soybean Seedlings Under Aluminum Stress

目的:探究镧对大豆铝胁迫的缓解效应;方法:以铝敏感大豆BD2为材料,进行50μmol/L铝胁迫处理,然后添加不同浓度氯化镧(10、100和1000 mg L/L)测定大豆幼苗抗氧化及光合指标;结果:与对照组相比较,铝胁迫导致大豆幼苗根系伸长率、根冠比、鲜重及干重显著降低,叶片SOD、POD活性显著降低,且MDA含量显著升高,叶绿素与类胡萝卜素含量、光合速率、蒸腾速率、气孔导度及胞间CO_2浓度也均显著下降;而与铝胁迫处理相比,不同浓度镧处理对大豆幼苗根长、鲜重与干重、SOD与POD活性有不同程度地促进作用,并显著降低MDA含量,同时提高叶绿素与类胡萝卜素含量,增强光合速率、蒸腾速率、气孔导度和胞间CO_2浓度,其中以10 mg/L镧处理效果最好;结论:适宜浓度的镧处理能够通过增强大豆幼苗的抗氧化能力,提高其光合性能,提高大豆幼苗对铝胁迫的适应能力,有效缓解铝对大豆幼苗生长的毒害。

Objective： To investigate the alleviation effects of trace earth element on soybean seedlings under alu- minum stress. Methods： Aluminum（A1） sensitive soybean cultivar B D2 was exposed to 50p,mol/L Al3 ＋ stress and determined the antioxidant performance and photosynthesis parameters after the addition of different concen- trations of lanthanum chloride （LaC13, 10, 100, 1000 mgL/L）. Results： Compared with the control, A1 stress led to significant decrease of root elongation rate, root - shoot ratio, fresh and dry weight as well as the SOD and POD activities, but caused the increase of MDA content of soybean seedlings. Al3 ＋ stress also resulted in the de- crease of chlorophyll and carotenoid contents, leaf photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration. However, comparing with the A1 stress treatment, addition of La can not on- ly promote the root elongation, root- shoot ratio, fresh and dry weight as well as SOD and POD activities while reduced the MDA content of soybean seedlings in varied degrees, but also enhance chlorophyll and carotenoid contents, photosynthetic rate, transpiration rate, stomatal conductance and intercellular CO2 concentration. And 10 mgL/L La was found to be the most effective concentration. Conclusions： Appropriate addition of LaCl3,therefore, can enhance the antioxidant capacity and the photosynthetic performance of soybean, through which enhances its tolerance to Al3 ＋ stress, and finally alleviates Al toxicity on the growth of soybean seedlings.