Abstract: The primary mechanism of significant increase in resistance of rice to low temperature photoinhibition was studied by foliar spray with 250 mg/L aqueous solution of 5-aminolevulinic acid (ALA). Low concentration ALA-treatment enhanced the resistance of rice to low temperature photoinhibition, for the significant enhancement of the ascorbate peroxidase (APX) and glutathione reductase (GR) activities as well as the less decline superoxide dismutase (SOD) activity which alleviates the photoinhibition of photosystem Ⅱ by reducing the accumulation of the hydrogen peroxide (H2O2) rather than strengthing the thermal energy dissipation through xanthophyll cycle. Moreover, the increased activity of APX was probably resulted in the accumulation of heme.

Key words: 5-aminolevulinic acid, rice, low temperature photoinhibition, anti-oxidant enzyme

摘要： 研究了喷施250 mg/L 5氨基乙酰丙酸（ALA）明显提高水稻对低温光抑制适应能力的主要机制。低浓度的ALA提高水稻耐低温强光的主要机制不是通过叶黄素循环加强热耗散，而是通过显著增加叶绿体抗氧化酶系统中抗坏血酸过氧化酶（APX）、谷胱甘肽还原酶（GR）的活性，减少超氧化物歧化酶（SOD）活性的下降，从而降低过氧化氢（H2O2）的含量，减轻PSⅡ的光抑制。而且，APX活性的增加可能是由于亚铁血红素库积累而引起的。

关键词: 5-氨基乙酰丙酸, 水稻, 低温光抑制