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[目的]为明确低磷、铝毒单独及复合胁迫下,不同水稻品种生理响应的差异。[方法]采用营养液培养试验,以秀水132(耐铝型)和甬优8号(铝敏感型)为材料,研究了各胁迫下幼苗干物质积累、光合能力和根系有机酸分泌量。[结果]低磷、铝毒胁迫下根系和地上部干重、叶绿素含量、光合速率、气孔导度和蒸腾速率均显著下降。低磷铝毒复合胁迫下幼苗干重及光合参数值均显著低于单一胁迫处理;酒石酸、苹果酸、柠檬酸和乙酸是根系各处理下分泌的主要有机酸。低磷、铝毒胁迫下根系乙酸、苹果酸和柠檬酸分泌量增加,复合胁迫时根系3种有机酸的分泌量高于单一胁迫处理。低磷、铝毒胁迫下水稻幼苗干重、光合能力及根系有机酸分泌存在显著的基因型差异。各胁迫下甬优8号植株干重和光合参数的下降幅度高于秀水132,而秀水132根系有机酸分泌量的增幅大于甬优8号。[结论]低磷铝毒复合胁迫引发水稻幼苗更严重的生理代谢抑制,以甬优8号表现更明显;复合胁迫下根系有机酸分泌量高于单一胁迫,以秀水132增幅更大。
[Objective] The research aimed to clarify the difference of physiological responses of different rice cultivars under single and combined stress of low phosphorus and aluminum toxicity. [Method] With nutrient solution culture experiment, the dry matter accumulation, photosynthetic capacity and root organic acid secretion of seedlings under different stress were studied using Xiushui 132 (aluminum tolerant) and Yongyou 8 (aluminum sensitive) as materials. [Result] The dry weight, chlorophyll content, photosynthetic rate, stomatal conductance and transpiration rate of root and shoot in low phosphorus and aluminum stress decreased significantly. The dry weight and photosynthetic parameters of seedlings under low phosphorus and aluminum toxicity were significantly lower than those under single stress. Tartaric acid, malic acid, citric acid and acetic acid were the main organic acids secreted by the roots. Under low phosphorus and aluminum stress, the exudation of acetic acid, malic acid and citric acid increased under root stress. The excretion of three kinds of organic acids in roots was higher than that of single stress under compound stress. Under low phosphorus and aluminum stress, there were significant genotypic differences in dry weight, photosynthetic capacity and organic acid secretion of rice seedlings. The decrease of dry weight and photosynthetic parameters of Yongyou 8 under stress was higher than that of Xiushui 132, while the increase of organic acid secretion of Xiushui 132 was greater than that of Yongyou 8. [Conclusion] The combination of low phosphorus and aluminum toxicity caused more severe physiological and metabolic inhibition in rice seedlings. The expression of Yongyou 8 was more obvious. Under combined stress, the organic acid secretion of root was higher than that of single stress, and the increase of Xiushui 132 was larger.