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Chinese Journal of Applied Ecology ›› 2016, Vol. 27 ›› Issue (8): 2527-2534.doi: 10.13287/j.1001-9332.201608.029

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Effects of different NO3--N/NH4+-N ratios on cucumber seedlings growth, nitrogen absorption and metabolism under suboptimal temperature and light intensity

ZHANG Xiao-cui1, LIU Yu-mei2, BAI Long-qiang1, HE Chao-xing1, YU Xian-chang1, LI Yan-su1*   

  1. 1Institute of Vegetables and Flowers, Chinese Academy of Agricultural Sciences, Beijing 100081, China;
    2Department of Landscape Engineering, Heze University, Heze 274000, Shandong, China
  • Received:2016-01-12 Published:2016-08-18
  • Contact: * E-mail: liyansu@caas.cn
  • Supported by:
    This work was supported by National Natural Science Foundation of China (31101583,31272212), Special Fund for China Morden Agriculture Technology Construction System (CARS-25-C-01), the Science and Technology Innovation Program of the Chinese Academy of Agricultural Sciences (CAAS-ASTIP-IVFCAAS), The Special Public Welfare Industry (Agriculture) Research Project (201203005) and Ministry of Agriculture Key Laboratory of Biology and Genetic Improvement of Horticultural Crops.

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Abstract: Cucumber (cv. Zhongnong 26) was used as material, the effects of NO3--N/NH4+-N ratios on growth and physiological characteristics of cucumber seedlings under suboptimal temperature and light intensity (18 ℃/10 ℃,180 ± 20 μmol·m-2·s-1) were studied. Total nitrogen in the nutrient solution was equal and three NO3--N/NH4+-N ratios, 26:2, 21:7 and 14:14, were applied as treatments. The results showed that cucumber treated by NO3--N/NH4+-N=21:7 had the longest total root length, the biggest root volume and root surface area, and the maximum number of root tips. H+-ATPase activity and relative expression of genes encoding nitrate transporter (NRT) and ammonium transporter (AMT) in cucumber roots were increased significantly by the treatment of NO3--N/NH4+-N=21:7. In addition, nitrate reductase (NR), glutamine synthetase (GS) and glutamate synthase (GOGAT) in cucumber leaves under the treatment of NO3--N/NH4+-N=21:7 were higher. As a result, the nitrogen content and biomass of cucumber were significantly increased. Compared with the plants under the treatment of NO3--N/NH4+-N=26:2 or 14:14, cucumber seedlings under the treatment of NO3--N/NH4+-N=21:7 had the highest biomass and total dry mass (DM) which were increased by 14.0% and 19.3% respectively under suboptimal temperature and light intensity. In conclusion, under suboptimal environmental conditions, NO3- -N/NH4+-N ratio could be adjusted to increase nitrogen absorption and metabolism of cucumber and alleviate the de-trimental effects caused by suboptimal conditions and promoted the cucumber growth.