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作 者 ：赵首萍, 张永志, 叶雪珠, 郑纪慈

期 刊 ：植物营养与肥料学报 2010年 16卷 3期 页码：681-687

关键词：小白菜；NRT；硝酸盐；基因型；

Keywords:Chinese cabbage, NRT, nitrate, genotype difference,

摘 要 ：以高硝酸盐积累品种四月慢和低硝酸盐积累品种华冠青梗菜为材料，采用溶液培养方法，测定了0.2和2 mmol/L NO^-₃处理下的硝酸盐积累量和硝酸还原酶活性，并应用Real-Time PCR技术检测了NO^-₃吸收基因NRT1和NRT2的表达量。结果表明： (1) 除0.2 mmol/L NO^-₃处理时的叶片硝酸盐含量没有显著差异外，四月慢植株各部位的硝酸盐含量都显著高于华冠青梗菜，高浓度培养使品种间硝酸盐积累量差异增加，四月慢对NO^-₃水平增加的响应能力强于华冠青梗菜。(2) 吸收液NO^-₃浓度1～20 mmol/L范围内，四月慢对NO^-₃离子吸收速率显著高于华冠青梗菜，且在高浓度下表现更显著。(3) 在 2 mmol/L NO^-₃处理下， _〖NRT2在根、叶片、叶柄中的表达量都是四月慢显著高于华冠青梗菜，_NRT1的表达量只有在根中四月慢显著高于华冠青梗菜，而在叶片和叶柄中都没有显著差异； 在0.2 mmol/L NO^-₃处理下，_NRT1和_〖NRT2表达情况相同，都是在叶片和叶柄中四月慢显著高于华冠青梗菜，而在根中表达量品种间没有显著差异。(4) _NRT1和_〖NRT2的表达在一定程度上可以解释硝酸盐积累量的差异，可能还有其他的基因对硝酸盐积累的基因型差异起重要作用，尤其是0.2 mmol/L NO^-₃处理时。(5) 四月慢的硝酸还原酶活性显著高于华冠青梗菜，即四月慢对硝酸根同化利用的能力强于华冠青梗菜。

Abstract:Two Chinese cabbage ［Brassica campestris ssp. chinensis (L. ) Makino］ cultivars (SYM and HGQGC) different significant in nitrate accumulation were used in our research to investigate the mechanism involved in nitrate absorption. With 0.2 and 2 mmol/L NO^-₃ treatments, the nitrate concentration, nitrate uptake rate, nitrate reductase activity (NRA) and the expression level of _NRT1 and _〖NRT2 were measured. The data suggested that firstly, the nitrate concentration in SYM was higher than that in HGQGC especially under higher nitrate treatment except for leaves with 0-2mmol/L NO^-₃ supply. The increment of nitrate concentration in SYM was also higher than that in HGQGC following the enhancement of nitrate in growing medium. Secondly, the nitrate uptake rate of SYM was higher than that of HGQGC with 0-20mmol/L NO^-₃ in growing medium, also especially with higher NO^-₃ solution. Thirdly, with 2mmol/L NO^-₃ treatment, the expression patterns of _〖NRT2 was consistent with the nitrate concentration in root, leaves and stem, that means the expression levels of _〖NRT2 in SYM was higher than that of HGQGC, while the same instance only occur in root for _NRT1 expression. under 0.2 mmol/L NO^-₃ treatment, only in stem the nitrate concentration, expression level of _NRT1 and _〖NRT2 were all higher in SYM than those in HGQGC. Fourthly, the different expression patterns of _NRT1 and _〖NRT2 maybe partly responsible for the different nitrate accumulation between cultivars and there must be some unknown genes also participated in nitrate accumulation especially in 0.2 mmol/L NO^-₃ treatment. Lastly, the NRA of SYM was also higher than HGQGC that means the higher nitrate use efficiency in SYM.

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