以番茄‘金棚一号’为材料,研究了外源γ-氨基丁酸(GABA)浸种处理对NaCl胁迫下种子萌发及幼苗生长和生理代谢的影响.结果显示:(1) NaCl胁迫显著抑制了番茄种子的萌发和胚根生长,同时导致番茄幼苗体内活性氧(O-·2、H2 O2)大量积累,膜脂过氧化程度加重,幼苗叶片光合系统Ⅱ活性显著降低,幼苗的生长受到严重抑制.(2)外源GABA浸种能够显著提高盐胁迫下番茄种子的萌发和胚根的生长,并以10.00 mmol·L-1 GABA浸种处理效果最好.(3)外源GABA浸种处理显著提高了NaCl胁迫下番茄幼苗根系和叶片抗氧化酶(SOD、POD和CAT)活性,降低了活性氧(O-·2、H2 O2)的产生和膜脂过氧化程度,通过维持较高的光合系统Ⅱ活性,促进了幼苗的生长及生物量积累,但GABA的缓解效应存在较大的浓度差异,其中以10.00 mmol·L-1GABA处理效果较好.研究表明,10.00 mmol·L-1 GABA浸种处理能够通过促进番茄种子萌发和幼苗生长来缓解盐胁迫的伤害.%The purpose of this paper was to study the effects of exogenous GABA in different concentration on seed germination,reactive oxygen species (ROS) metabolism and chlorophyll fluorescence parameters in seedlings of under NaCl stress. Also,tomato plug-seedlings were irrigated with nutrient solution containing 200 mmol · L-1 NaCl in vermiculite. The results showed that: (l)Tomato seed germination ratio and radical growth were inhibited, and photosynthetic system D activity was significantly decreased by increasing ROS accumulation (O2 ,H2O2) and membrane lipid peroxidation level,which severely inhibited the growth of tomato seedlings. (2)Tomato seeds pretreated with different concentration GABA solution showed increased seed germination ratio and radical growth,in which 10. 00 mmol · L-1 GABA treatment was the best under saline stress. (3) With 200 mmol · L-1 NaCl stress, seedlings treated with exogenous GABA soaking especially 10. 00 mmol · L-1 GABA showed significantly increased antioxidant enzyme (SOD, POD,CAT) activities,as well as decrease in accumulation of O2 , H2O2 and membrane lipid peroxidation,so alleviated salt injury induced by NaCl. Furthermore, seedling height and biomass with GABA treatment were improved accordingly through maintaining higher photosynthetic system II activity. In summary,soa-king treatment with 10. 00 mmol · L-1 GABA had more favorable effects on tomato seed germination and seedlings growth under saline stress.
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