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氮是茶树重要的营养元素之一。茶树所吸收的土壤氮或肥料氮绝大部分为无机氮(铵态氮或硝态氮),施入土中的铵态氮肥常在土壤微生物的作用下转化为硝态氮。由于硝态氮在土壤中的移动性极强,因而淋失率很高。茶树具有明显的喜铵性,对硝态氮的同化利用率很低(仅为对铵态氮的1/4左右),因此,增强茶树吸收同化硝态氮的能力,有利于提高茶树对土壤和肥料氮的利用率。 硝酸还原酶被认为是硝态氮吸收同化过程中主要的限速酶,尤其对于喜硝态氮作物,硝酸还原酶在氮素同化营养中起着关键作用。Wickremasinghe(1680)、Barua(1984,1986)和王湘平、苏金为(1991)等的研究业已证实硝酸还原酶活性与茶叶产量及氮的吸收效率有密切关系。本研究进一步探讨茶树硝酸还原酶活性及其调控因素,旨在揭示茶树的氮素营养特性,为寻求提高茶树氮利用率的途径提供科学依据。
Nitrogen is one of the important nutritional elements of tea tree. Most of the soil nitrogen or fertilizer nitrogen absorbed by the tea tree is inorganic nitrogen (ammonium nitrogen or nitrate nitrogen). The ammonium nitrogen fertilizer applied to the soil is often transformed into nitrate nitrogen by the soil microorganism. Due to the strong mobility of nitrate nitrogen in the soil, the leaching rate is very high. Tea tree has a significant ammonium ammonium, the assimilation and utilization of nitrate nitrogen is very low (only about 1/4 of ammonium nitrogen), therefore, to enhance the ability of tea trees to assimilate and assimilate nitrate nitrogen is conducive to improving the tea plant on soil And fertilizer nitrogen utilization. Nitrate reductase is considered as the main rate-limiting enzyme in nitrate assimilation and assimilation process, especially for nitrate-like crop and nitrate reductase plays a key role in nitrogen assimilation nutrition. Studies by Wickremasinghe (1680), Barua (1984, 1986) and Wang Xiangping and Su Jinwei (1991) have confirmed that nitrate reductase activity is closely related to tea yield and nitrogen uptake efficiency. This study further explored the nitrate reductase activity of tea plants and its regulatory factors, aimed at revealing the nitrogen nutrition characteristics of tea trees and providing a scientific basis for seeking ways to improve the nitrogen utilization rate of tea trees.