不同形态氮素及其配比对铁核桃实生苗叶片光合特性和养分含量的影响

Effects of different form nitrogen and ratios on the photosynthetic characteristics and nutrient contents in leaves of Juglans sigillata seedling

【目的】摸清铁核桃(Juglans sigillata)氮素营养生理特性,为铁核桃幼苗氮肥合理应用提供科学依据。【方法】采用盆栽土培实生苗试验,研究铵态氮、硝态氮和酰胺态氮[CO(NH2)2]及其配比对铁核桃叶片净光合速率(Pn)、蒸腾速率(Tr)、气孔导度(Gs)、胞间CO2浓度(Ci)及叶片光合色素和可溶性糖、淀粉、营养元素等的影响。【结果】NO3--N与NH4+-N按照各50%混合施用时,叶片的Tr、Ci、Gs、Chl.a、Chl.b、Chl.a+b、可溶性糖、淀粉和氮、磷、钾、钙、镁、铁、锰、铜、锌、硼的含量及Pn在所试配比中都最高;单一施用CO(NH2)2、NH4+-N或NO3--N时,上述指标都较低,Pn下降;在各处理中,单一施用NO3--N的叶片气体交换参数指标、光合色素和养分含量和Pn最小。【结论】铁核桃实生苗不具喜NO3--N特性;氮素形态及其配比对铁核桃实生苗叶片光合特性及养分含量影响明显,在NO3--N与NH4+-N的混合比例超过50%或单一施用CO(NH2)2、NH4+-N、NO3--N时不利于铁核桃实生苗叶片光合同化积累及营养元素的吸收。

[Objective]The objective of the study is to explore the nitrogen nutrition physiological characteristics of walnut （Juglom sigillata） and to provide the scientific basis for the reasonable application of nitrogen fertilizer of walnut seedling. [Method]The effects of different form nitrogen including NH4＋-N, NO3--N and CO（NH2）2 and ratios on net photosynthetic rate（Pn）, transpiration rate（Tr）, stomatal conductance（Gs）, intercellular CO2 concentration（C0 of J. sigillata leaves and the contents of photosynthetic pigment, soluble sugar and starch, nutrient element in leaves were studied by using soil culture in pot. [Result]The results showed that under the mixed supply of NO3--N and NH4＋-N at the ratio of 50：50, Tr, Ci, Gs and contents of Chl.a, Chl.b, Chl.a＋b, soluble sugar, starch, N, P, K, Ca, Mg, Fe, Mn, Cu, Zn and B in leaves and Pn of leaves were all the highest. Under the sole supply of CO（NH2）2, NH4＋-N or NO3--N, those indicators were all lower and Pn was decreased. Under the sole supply of NO3-- N, the gas exchange parameter indexes of photosynthesis and the contents of photosynthetic pigment and nutrients in leaves were the lowest and Pn was the smallest. [Conclusion]J. sigillata seedling had no nitrate-liking feature. The effects of nitrogen forms and ratios on photosynthetic characteristics and nutrient contents in leaves of J. sigillat seedling were remarkable. Under the mixed supply of NOs--N and NH4＋-N at the ratio of more than 50% and the sole supply of CO（NH2）2, NH4＋-N or NO3--N, the adverseeffects on photosynthesis assimilation accumulation and the absorption to nutrient elements of J. sigillat seedling was caused.