硝态氮浓度对长春花体内生理代谢指标的影响

Effects of Nitrate Nitrogen Content on Physiological indicators of Catharanthus roseus

以药用植物长春花为研究对象,通过施加不同浓度硝态氮,揭示其体内长春碱积累受氮水平的调控特征及其与内源碳/氮(C/N)代谢的联系。结果表明,中等浓度的氮水平能显著诱导根系和叶片中硝酸还原酶活性的提高,并且该效应依赖于处理时间,处理12 h后其诱导效果最为显著。对比氮代谢,测定了叶片中蔗糖的质量分数,在外施18 mmol·L-1NO-3溶液后6 h内蔗糖质量分数低于对照水平,之后又升高至对照水平。HPLC检测叶片中长春碱的结果显示,经不同浓度硝态氮处理2 h后显著诱导长春碱质量分数增加。

Catharanthus roseus were investigated for the characteristics of the alkaloids accumulation and the metabolism ot en- dogenous carbon/nitrogen （C/N） of plants by applying different nitrate contents. The medium concentration of nitrogen can significantly induce NR activity in roots and leaves of C. roseus. In different processing time （20 min, 2 hours, 6 hours, 12 hours and 24 hours）, the content of nitrate reductase （NR） activity （ μg·h^-1·g^-1 ） is the most significant in roots and leaves after 12 hours. Compared with the contents of nitrogen metabolism, the content of sucrose in leaves is less than that of control in the concentration of nutrient solution （NO3 ） with 18 mmol ·L^-1for 6 hours, which is increased to the levels of control after 6 hours. The alkaloids content is increased in Medium content of nitrogen for 2 hours according to the HPLC detection. The alkaloids accumulation is closely related to endogenous carbon and nitrogen metabolism of plants in different exogenous nitrate levels.