The effect of different nitrogen source ratios, which the ratio of NO3--N to NH4+-N were 100 : 0, 75 : 25,50 : 50,25 : 75 and 0 : 100, on the seedling growth of Hovenia acerba were studied by sand culture method. The results indicated that with the increase of nitrate nitrogen ratio, the plant height, stem diameter, branch number and biomass of the H. acerba were ascending. The plant height and stem diameter with the ratios of NO3--N to NH4+-N equal to 100 : 0 and 75 : 25, as well as branch number and whole plant biomass with ration of, 75 : 25 were significantly higher than other treatments. With the ratios equal to 75 : 25 and 50 : 50, the median leaf area were the highest. While median leaf area was the smallest with the ratio of 0 : 100, and the leaf apex withered and curled. The content of chlorophyll a and chlorophyll b in the treatment with ratio of 50 : 50 were significantly lower than those in other treatments. The soluble sugar content in leaves treated with ratio of 100 : 0, 75 : 25 and 0 : 100 increased significantly. The leaf nitrogen contents with raitio of 75 : 25 and 100 : 0 were significantly lower than those of other treatments. The nitrogen content of the stem with ratio of 50 : 50 was the lowest, and the nitrogen content with ratio of 75 : 25 root was significantly lower than that of 0 : 100. However, the difference with other treatments was not significant. The nitrogen content with ratio of 0 : 100 was significantly higher than that of other treatments, showing the short plants and decaying roots. It can be seen that nitrogen source and proportion significantly affect the growth of H. acerba, single ammonium nitrogen is unfavorable to the growth of H. acerba, and the ratio of NO3--N to NH4+-N equal to 75 : 25 is more suitable for the growth of H. acerba.%采用砂培的方法研究不同氮素比例(NO3--N:NH4+-N为100:0、75:25、50:50、25:75、0:100)对枳椇(Hovenia acerba)幼苗生长的影响.结果表明:随着硝态氮比例的增加,枳椇的株高、茎粗、分枝数以及生物量呈上升趋势,其中硝铵比为100:0与75:25处理的株高与茎粗,75:25处理的分枝数与全株生物量显著高于其他处理;硝铵比为75:25和50:50处理的中位叶面积最大,0:100处理中位叶面积最小,叶尖枯萎卷曲;硝铵比为50:50处理的叶绿素a及叶绿素b含量显著低于其它处理;100:0、75:25与0:100处理的叶可溶性糖含量显著升高;75:25与100:0的叶含氮量极显著低于其他处理,50:50的茎含氮量最低,75:25的根含氮量显著低于0:100,与其他处理差异不显著.0:100处理的枳椇各器官的含氮量极显著高于其他处理,同时表现为植株矮小,根系有腐烂现象.综上可见,氮素形态和比例显著影响枳椇生长,单一铵态氮不利于枳椇的生长,硝铵比为75:25较适宜枳椇的生长.
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