不同氮素形态配比对花榈木幼苗根系生长及氮代谢关键酶活性的影响

Effects of Different Nitrogen Forms Ratios on Root Growth and Activities of Key Enzymes in Nitrogen Metabolism in Ormosia henryi Prain Seedlings

为探究最适于花榈木幼苗生长的氮素形态配比,采用氮素形态配比为NH_(4)^(+)∶NO_(3)^(-)=10∶0、5∶5、0∶10及以改良霍格兰标准营养液为对照的营养液,共4个处理,对花榈木1 a生幼苗进行处理。结果表明,处理期间氮素配比为NH_(4)^(+)∶NO_(3)^(-)=5∶5时,花榈木幼苗根系形态指标及硝酸还原酶和谷氨酰胺合成酶活性均显著大于其他处理,可知花榈木幼苗根系喜欢混合氮源,且铵硝1∶1均衡配比更利于氮素吸收和代谢,而单一氮源营养液对于花榈木幼苗生长的促进效果不佳,其中全铵营养液会抑制幼苗生长,降低硝酸还原酶活性。

To determine the optimum nitrogen ratio for the growth of Ormosia henryi Prain seedlings,a modified Hoagland standard nutrient solution was used as the control,four treatments were set in this study using annual seedlings of Ormosia henryi Prain,treated with the nutrient solution with NH_(4)^(+)∶NO_(3)^(-)=10∶0、5∶5、0∶10.The results showed that during the treatment period,when the nitrogen ratio was(NH_(4)^(+)∶NO_(3)^(-)=5∶5)the root morphological indexes and the activities of NR and GS of Ormosia henryi Prain seedlings were significantly higher than those in the other treatments.This suggests that Ormosia henryi Prain seedlings exhibit a preference for mixed nitrogen sources,and a balanced ratio of ammonium nitrate 1∶1 is more conducive to nitrogen absorption and metabolism.In contrast,the single nitrogen source nutrient solution has a limited effect on the growth of Ormosia henryi Prain seedlings.The total ammonium nutrient solutions can inhibit seedling growth and reduce nitrate reductase activity.