磷对铝胁迫下荞麦根际土壤铝形态和酶活性的影响

Effects of phosphorus on aluminum forms and soil enzymatic activities of buckwheat rhizosphere under aluminum stress

采用土培法,以耐铝性明显差异的两个荞麦Fagopyrum esculentum基因型"江西荞麦"(耐性)和"内蒙荞麦"(敏感)为材料,研究铝胁迫下磷对荞麦生长和根际土壤铝形态、土壤酶活性的影响。结果表明,0.4g·kg-1铝配施0.2g·kg-1磷的内蒙和江西荞麦根系生物量分别比不施磷组增加了67.9%和21.2%,磷能显著缓解铝对荞麦根系生长的抑制,提高根系生物量和根冠比。磷铝互作下根际土壤的交换态铝含量显著降低,毒性较小的吸附态羟基铝和络合态铝含量显著增加。根际土壤酶活性变化复杂,过氧化氢酶活性与磷质量分数呈正相关,wp=0.2g·kg-1对铝胁迫下荞麦根际土壤转化酶活性最有利。说明施磷降低铝胁迫根际土壤的交换态铝含量,提高土壤过氧化氢酶活性,减缓铝毒对植株生长的抑制作用。

Two different Al tolerence buckwheat that were Neimeng（Al tolerant） and Jiangxi （Al sensitive） were compared under aluminum stress. The effects of P on buckwheat growth,Al forms and soil enzymatic activities of root rhizosphere microecology under Al toxicity were studied by using methods of soil culture. The results revealed that the biomass of Neimeng and Jiangxi buck-wheat supplied with 0.2 g·kg^-1 P and 0.4 g·kg^-1Al were 67.9% and 21.2% higher than that supplied without P. P could ameliorate the inhibition of Al on root elongation,enhance the root biomass and root-to-shoot ratio. P and Al interaction significantly decreased both exchangeable Al （ExAl）,while increased hydroxyl Al （HyAl） and organically complexed Al （OrAl） content of rhizosphere soil that were low toxicity. Changes of soil enzyme activities in Rhizosphere was complexity. Catalase activities showed positive correlation with P. 0.2 g·kg^-1 P was the most convenient concentration for catalase activities. These results indicated that P application may alleviate Al toxicity by decreasing ExAl content and enhancing catalase activity of rhizosphere soil.