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目的:探讨不同氮素形态对夏枯草生长及光合特性的影响,为夏枯草氮肥的合理施用提供一定依据。方法:采用水培法,测定在等氮水平(15 mmol.L-1)不同铵硝比处理下,夏枯草叶面积、生物量、叶绿素含量及光合相关参数。结果:随着铵硝比的下降,夏枯草叶面积先增加后下降,全铵营养(NH4+-N∶NO3--N为100∶0)下最小,当NH4+-N∶NO3--N为25∶75时最大;随硝态氮比例的提高,夏枯草全株鲜重不断增加,在全硝处理时达到最大,是全铵处理的5.11倍;而全株干重则以NH 4+-N∶NO 3--N为25∶75的最大,且与全硝处理无显著差异。铵硝比为50∶50时叶片中总叶绿素、类胡萝卜素含量最高。铵硝比为25∶75时,夏枯草净光合速率(Pn)最大,全铵处理下最低。结论:在总氮水平为15 mmol.L-1下,适量增加硝态氮比例,有利于促进夏枯草苗期生长、提高干物质积累和净光合速率。
Objective: To investigate the effects of different nitrogen forms on the growth and photosynthetic characteristics of Prunella vulgaris, and provide some evidences for the rational application of Prunella vulgaris nitrogen fertilizers. Methods: The leaf area, biomass, chlorophyll content and photosynthetic parameters of Prunella vulgaris under different nitrogen and nitrogen ratios (15 mmol·L -1) were determined by hydroponics. Results: The leaf area of Prunella vulgaris first increased and then decreased with the decrease of NH4 + -N ratio. NH4 + -N:NO3 - N was the lowest at NH4 + -N: NO3 - N of 100: : 75. With the increase of the proportion of nitrate nitrogen, the fresh weight of Prunella vulgaris increased continuously and reached 5.11 times of the total ammonium treatment, : NO 3 - N is 25:75 at the maximum, and no significant difference with the whole nitrate treatment. Ammonium nitrate ratio of 50:50 leaf chlorophyll, carotenoids content highest. When the ratio of ammonium to nitrate was 25:75, the net photosynthetic rate (Pr) of Prunella vulgaris was the highest, and the lowest under the whole ammonium treatment. CONCLUSION: When the total nitrogen level is 15 mmol·L-1, the appropriate amount of nitrate increases the growth of Prunella vulgaris at seedling stage, and increases the dry matter accumulation and net photosynthetic rate.