高温胁迫下外源GABA对黄瓜幼苗生长的影响

以清白黄瓜为材料,在高温(40℃/35℃,昼/夜,各12 h)条件下研究了外源γ-氨基丁酸(GABA)对黄瓜幼苗形态生长、光合特性、生理代谢的影响。试验结果表明,高温胁迫下,外源GABA显著增加了黄瓜幼苗的株高、茎粗、叶面积,增强了壮苗指数、根冠比和根系活力,降低了叶片相对电导率(REC)和丙二醛(MDA)含量,减缓了叶绿素的分解,提高了渗透调节物质脯氨酸(Pro)和可溶性糖(SSC)含量,并有效增强了抗氧化酶(SOD、POD、CAT、APX)活性及光合作用,使Pn、Gs、Tr加强,Ci积累减少,缓解了高温对黄瓜幼苗的伤害,可维持植株正常生长,以10 mmol/L GABA处理效果最优。

Effects of Exogenous GABA on Growth of Cucumber Seedlings under High Temperature Stress

Taking Qingbai cucumber as material, we studied the effects of exogenous γ-aminobutyric acid (GABA) on seedling growth, photosynthetic characteristics and physiological metabolism under high temperature (40℃/35℃). The results showed that, under high temperature stress, exogenous GABA significantly promoted the growth of plant height, stem diameter, leaf area of cucumber seedlings, and enhanced sound seedling index, root-shoot ratio and root activity, while reduced REC and MDA content of leaves, with chlorophyll decompose slowed down, and Pro and SSC content increased. In addition, exogenous GABA effectively enhanced the activity of antioxidant enzymes (SOD, POD, CAT, APX) and photosynthesis, and increased Pn, Gs, Tr, while decreased Ci accumulation, thereby relieved the damage of high temperature on cucumber seedlings and maintained plant normal growth, among which 10 mmol/L GABA treatment had the best effect.