γ-氨基丁酸对枇杷幼果耐寒性的影响

为探索外源γ-氨基丁酸(GABA)对枇杷幼果耐寒性的影响,分别对5年生‘川早枇杷’幼果喷施0、1、5、10、20 mmol.L_-1^GABA溶液一周后,于人工气候箱-3℃处理24h,研究GABA对低温胁迫下枇杷幼果相对电导率(REC)、丙二醛(MDA)含量、抗氧化酶活性及渗透调节物质含量的影响。结果表明,与对照相比低温胁迫使枇杷幼果的REC、MDA含量和冻害指数显著升高,而经外源GABA处理后其REC、MDA含量和冻害指数显著下降。另外,经GABA处理后枇杷幼果的超氧化物歧化酶活性、抗坏血酸过氧化物酶活性、可溶性糖含量、可溶性蛋白含量和脯氨酸含量较0 mmol.L_-1^处理显著升高,并与REC和MDA含量呈极显著负相关的关系。综上,外源GABA能够通过提高抗氧化酶活性和渗透调节物质含量来缓解冻害对枇杷幼果造成的不利影响,其中20 mmol.L_-1^GABA处理对枇杷幼果耐寒性的增强效果最好。

Effects of γ-Aminobutyric acid on the Cold Tolerance of Young Loquat Fruits

In order to explore the effects of exogenous γ-aminobutyric acid (GABA) on the cold tolerance of young loquat fruits. 5-year-old "Chuanzao loquat" young fruits were sprayed with 0, 1, 5, 10, and 20 mmol.L_-1 GABA solution for one week and then treated with -3℃ for 24h in an artificial climate chamber. The effects of GABA on relative electrical conductivity (REC), malondialdehyde (MDA) content, antioxidant enzymes activity and osmoregulatory substances content of young loquat fruits were investigated. The results showed that REC, MDA content and freezing index of young loquat fruits were significantly increased by low temperature stress, whereas their REC, MDA content and freezing index were significantly decreased by exogenous GABA treatmen. In addition, the superoxide dismutase activity, ascorbate peroxidase activity, soluble sugar content, soluble protein content and proline content of young loquat fruits treated with GABA significantly increased compared with those treated without 0 mmol.L_-¹ GABA, and showed a highly significant negative correlation with REC and MDA content. In conclusion, exogenous GABA can alleviate the adverse effects of frost damage on young loquat fruits by increasing the activity of antioxidant enzymes and osmoregulatory substances content, among which the 20 mmol.L_-1 GABA treatment had the best effect on the enhancement of cold tolerance of young loquat fruits.