Effects of different stress treatments on γ-aminobutyric acid(GABA)content in cabbage | 不同胁迫处理方法对结球甘蓝GABA含量的影响

Chinese. 以结球甘蓝(Brassica oleracea var.capitata L.)为试材,研究不同机械切分大小、4℃低温贮藏和浸泡胁迫处理对γ-氨基丁酸(GABA)含量和谷氨酸脱羧酶(GAD)活性的影响。结果表明:机械切分、低温贮藏和浸泡处理均可提高GABA含量和GAD活性。切分大小为0.5 cm×3.0 cm的外叶和内叶中GABA含量最高,分别为1.20 mg・g-1和1.88 mg・g-1,内叶显著高于外叶。4℃下贮藏1.5 h时外叶和内叶中的GABA含量达到最大值,分别为1.77和2.41 mg・g-1,且对应的外叶中GAD活性和GABA含量显著低于内叶。100 μmol・L-1 CaCl2溶液浸泡2 h,内叶GABA含量为2.32 mg・g-1,外叶为1.52 mg・g-1。在pH 5.6的磷酸-柠檬酸缓冲液中浸泡2 h,内叶GABA含量最高为2.01 mg・g-1,而外叶在pH 6.0时达到最大值1.47 mg・g-1。10 g・L-1谷氨酸钠浸泡处理4 h时GABA含量显著增加,内叶为1.36 mg・g-1,外叶为1.04 mg・g-1,内叶显著高于外叶;浸泡过程中,内叶GAD活性较外叶变化显著。

English. The changes of γ-aminobutyric acid(GABA)content,and the activity of glutamic acid decarboxylase(GAD)in the outer and inner leaves of the fresh cabbage(Brassica oleracea var.capitata L.)treated by cutting different sizes,storaging at a low temperature of 4℃ and soaking into solution were observed.The results showed that the GABA contents in both outer and inner leaves with the segmentation size of 0.5 cm×3.0 cm reached the maximum value of 1.02 mg・g-1 and 1.88 mg・g-1,respectively,and the GABA content in inner leaves was significantly higher than that in the outer leaves.The outer and inner leaves with the size of 0.5 cm×3.0 cm were storaged at 4℃,the GABA contents in the outer and inner leaves storaged for 1.5 hours reached the maximum value of 1.77 mg・g-1 and 2.41 mg・g-1,respectively,and the GABA content in the outer leaves was significantly lower than that in the inner.Correspondingly,the GAD activities in the outer and inner leaves storaged for 1.5 hours were also highest.It was observed that the GABA contents in inner and outer leaves soaking into CaCl2 with the concentration of 100 μmol・L-1 reached the maximum values of 2.32 mg・g-1 and 1.52 mg・g-1,respectively.It was also observed that the GABA contents in inner leaves soaking into the phosphate-citric acid buffer solution with the pH value of 5.6 reached the maximum value of 2.01 mg・g-1,but the GABA content in outer leaves reached the maximum value of 1.47 mg・g-1 into the same buffer solution with the pH value of 6.0.It was also observed that the GABA contents in the inner and outer leaves soaking into the 10 g・L-1 sodium glutamate for 4 h reached the maximum values of 1.36 mg・g-1 and 1.04 mg・g-1,respectively,and the GABA content and GAD activities in the outer leaves were significantly lower than those in the inner.