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Chinese Journal of Applied Ecology ›› 2016, Vol. 27 ›› Issue (12): 3987-3995.doi: 10.13287/j.1001-9332.201612.017

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Effect of exogenous γ-aminobutyric acid on NO3--N assimilation in muskmelon under Ca(NO3)2 stress

ZHEN Ai1,2,3, HU Xiao-hui1,2,3, REN Wen-qi1,2,3, SU Chun-jie1,2,3, JIN Xiao-qing1,2,3, SUN Xian-peng1,2,3   

  1. 1College of Horticulture, Northwest A&F University, Yangling 712100, Shaanxi, China;
    2Key Laboratory of Protected Horticultural Engineering in Northwest, Ministry of Agriculture, Yangling 712100, Shaanxi, China;
    3Shaanxi Province Facility Agriculture Engineering Center, Yangling 712100, Shaanxi, China
  • Received:2016-05-03 Online:2016-12-18 Published:2016-12-18
  • Contact: * E-mail: hxh1977@163.com
  • Supported by:
    This paper was supported by the Innovation Project of Science and Technology Plan of Shaanxi Province (2015KTTSNY03-03), Special Projiect of China Morden Agricultural Industry System Construction (CARS-25-D-02) and Doctors’ Scientific Research Start-up Foundation of Northwest A&F University (Z109021104).

Abstract: The effect of exogenous γ-aminobutyric acid (GABA) on NO3--N assimilation in muskmelon under Ca(NO3)2 stress was investigated in ‘ Yipintianxia 208’, a salt-sensitive melon variety cultured under deep flow hydroponics which simulated soil salinization. The results showed that under Ca(NO3)2 stress, the activities of nitrate reductase (NR), glutamate synthetase (GS) and glutamate amino transferase (GOGAT) in muskmelon seedlings were significantly reduced, while the activities of glutamate dehydrogenase (GDH), glutamate oxaloacetate transaminase (GOT) and glutamate pyruvate aminotransferase (GPT) were enhanced, leading to increased contents of NH4+-N and total amino acids, and decreased contents NO3--N and soluble protein in muskmelon, which further severely inhibited plant growth and photosynthesis of muskmelon seedlings. Exogenous GABA effectively improved the absorption of NO3--N in muskmelon roots and its transportation from root to shoot under Ca(NO3)2 stress, and improved NH4+-N assimilation by enhancing NR, GS and GOGAT activities in muskmelon seedlings. Exogenous GABA also reduced NH4+ release by limiting GDH deamination, thus further alleviated the toxication of NH4+-N induced by Ca(NO3)2 stress. In addition, foliage spraying of GABA could regulate amino acids metabolic pathways and promote protein synthesis. The results suggested that exogenous GABA could improve NO3--N assimilation and regulate amino acids metabolism to alleviate Ca(NO3)2 stress damage in muskmelon seedlings.