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为了探讨赤霉素(GA)对黄瓜在根区亚低温下氮(N)吸收和代谢的影响机理,以营养液栽培的‘中农26’黄瓜为试材,研究了外源GA对黄瓜在根区亚低温下叶片叶绿素荧光参数、光合参数和碳(C)、氮代谢平衡调节酶活性的影响。结果表明:与根区适温处理相比,根区亚低温使黄瓜幼苗生长受抑,叶片光系统Ⅱ(PSⅡ)的光化学活性、光合放氧速率、净光合速率(Pn)、磷酸烯醇式丙酮酸羧化酶(PEPCase)和蔗糖磷酸合成酶(SPS)活性等降低,单株C与N积累量的比值(C/N)升高,N代谢消耗的能量减少。外源GA处理缓解了根区亚低温对黄瓜生长的抑制,使PSⅡ光化学活性、光合放氧速率、Pn、PEPCase和SPS活性都有不同程度的提高,C/N值和N代谢消耗的能量恢复至与根区适温处理相当的水平。表明,外源GA可以通过增强光能捕获和CO_2同化能力,调节N、C代谢平衡,促进根区亚低温下黄瓜对N的吸收与代谢。
In order to explore the mechanism of gibberellin (GA) on nitrogen (N) uptake and metabolism of cucumber in the root zone, we studied the effects of exogenous GA on cucumber And chlorophyll fluorescence parameters, photosynthetic parameters and carbon (C), nitrogen balance balance regulators in the region under mild hypothermia. The results showed that compared with the moderate temperature treatment in root zone, the hypothermia in the root zone inhibited the growth of cucumber seedlings, the photochemical activity of PSⅡ, the photosynthetic oxygen evolution rate, net photosynthetic rate (Pn), phosphoenol The activity of PEPCase and SPS decreased, the C / N ratio increased and the energy consumed by N metabolism decreased. Exogenous GA alleviated the inhibition of the growth of cucumber at the root zone, and increased the photochemical activity of PSⅡ, the rate of photosynthetic oxygen evolution, the activity of Pn, PEPCase and SPS, and restored the energy consumption of C / N and N metabolism To the root zone and appropriate temperature treatment level. The results showed that exogenous GA can regulate the balance of N and C metabolism and enhance the uptake and metabolism of N by cucumber in the root zone under the mild hypothermia by enhancing light harvesting and CO 2 assimilation ability.