摘要
利用NO3--N/NH4+-N为100∶0和75∶25的营养液对两个硝酸盐累积能力显著不同的小白菜品种(上海青和亮白叶1号)进行培养,测定了小白菜叶片、叶柄及根系硝酸盐含量、硝态氮和铵态氮吸收量及各部位硝酸还原酶活性,以探讨适当增铵降低小白菜硝酸盐含量以及小白菜不同品种和不同器官累积硝酸盐能力差异的机理。结果表明,适当增铵使叶片、叶柄和根系硝酸盐含量分别降低了22%、15%和22%,而硝态氮吸收量则降低了7.5%。小白菜各器官硝酸盐含量为叶柄>叶片>根系。叶片硝酸还原酶活性分别是叶柄和根系的27和9倍,呈现叶片>根系>叶柄,叶片是硝态氮的主要还原器官。亮白叶1号叶片、叶柄及根系硝酸盐含量分别较上海青高3%、38%和34%,硝态氮吸收量仅较上海青高11%;而叶片、叶柄及根系硝酸还原酶活性则分别较后者降低44%、56%和38%。适当增铵减少硝态氮吸收量是增铵降低硝酸盐含量的主要原因。不同器官的功能与结构的不同决定其累积硝酸盐能力的不同;不同品种硝酸盐累积的差异取决于还原硝态氮能力的差异。
In order to study the underlying mechanisms of properly enhancing ammonium to reduce nitrate content in Chinese cabbages and the nitrate accumulation capacity of different cuhivars and different organs of Chinese cabbie, nitrate contents in leaf blades, petioles and roots, the amonut of nitrate and ammonium adsorptive capacity and nitrate reductase activity of these three organs of the two cuhivars of Chinese cabbage （Shanghaiqing, SHQ and Liangbaiye 1, LB1 ）, incubated using two nutrient solution with NO3^- -N/NH4^＋ -N being 100 ： 0 and 75 ： 25 respectively, were assayed. The results obtained indicated that properly enhancing ammonium reduced nitrate content in leaf blades, petioles and roots by 22%, 15% and 22% respectively, but adsorptive capacity of nitrate was reduced by 7.5%. The nitrate contents in different organs were： petioles 〉 leaf blades 〉 roots. Nitrate reductase activity （NRA） in leaf blades was 27 and 9 times higher than that in petioles and roots, respectively. Leaf blade was the main organ responsible for the reduction of nitrate. Nitrate contents in leaf blades, petioles and roots of Liangbaiye 1 were higher than those in the organs of Shanghaiqing by 3 %, 38 % and 34%, respectively. The amount of nitrate taken up by Liangbaiye 1 was only 11% more than that taken up by Shanghaiqing, but the nitrate reducatse activity of leaf blades, petioles and roots was 44 %, 56 % and 38 % lower than those of Shanghaiqing. The falling of accumulation of nitrate in plants was mainly attributed to the proper enhancing ammonium reduced the adsorptive capacity of nitrate. Different functions and different construction of organs resulted in their different nitrate accumulation capacity. The variance of nitrate accumulation of different cultivars laid on the variance of the ability in the reduction of nitrate.
出处
《植物营养与肥料学报》
CAS
CSCD
北大核心
2005年第6期800-803,共4页
Journal of Plant Nutrition and Fertilizers
基金
国家自然科学基金资助项目(项目编号30270790)资助
关键词
适当增铵
硝酸盐含量
小白菜
器官
properly enhanced ammonium
nitrate content
Chinese cabbage
organ
