不同氮素形态对番茄幼苗碳、氮积累的影响

Effects of Nitrogen Forms on Carbon and Nitrogen Accumulation in Tomato Seedling

【目的】探讨番茄幼苗生长及其根系、叶片碳氮积累动态对无机氮(NH4+-N、NO3--N),氨基态氮(Glycine)的不同响应。【方法】采用2个番茄品种(‘申粉918’、‘沪樱932’),水培条件下设置相同氮浓度(3.0mmol·L-1N)的NH4+-N、NO3--N、Glycine(甘氨酸)3个处理,测定番茄幼苗株高、干物质重、叶绿素含量、根系活力、根系叶片碳氮含量和植株总氮量。【结果】在无机氮(NH4+-N、NO3--N)和氨基态氮(Gly-N)存在的营养介质中,番茄幼苗在处理前期(如处理后8d或16d)的株高、生物量、植株总氮量等各处理间差异不显著,而其后则表现为NO3--N>Gly-N>NH4+-N,处理间差异显著,且品种间差异显著(P<0.05)。Gly-N处理显著提高了番茄幼苗叶片的叶绿素含量,NH4+-N培养导致番茄根系活力显著下降。不同氮素形态对番茄叶片的全碳含量影响不大,而NH4+-N、Gly-N处理则显著提高了番茄根系全碳、叶片及根系全氮含量,且NH+4-N处理的增加效应大于Gly-N处理。在处理前期(如处理后8d或16d),植株全碳积累量表现为NO3--N>NH4+-N>Gly-N,而其后则表现为NO3--N>Gly-N>NH4+-N;植株氮吸收量均表现为NO3--N>Gly-N>NH4+-N。【结论】氮素形态不同,对植物产生的生理效应不同。氨基态氮(Gly-N)也可以成为番茄生长的氮源。不同品种对氨基态氮的吸收利用能力不同。

[Objective] The aims of this study were to investigate the plant growth, C and N accumulation in leaves and roots of tomato seedlings in response to inorganic （NH4^＋-N, NO3^--N） and organic （Gly-N） nitrogen. [ Method ] Different forms of nitrogen （NH4^＋-N, NO3^--N, Gly-N） were supplied to two tomato cultivars （＇Shenfen918＇ and ＇Huying932＇） using a hydroponics system. Plant dry biomass, chlorophyll content, root activity, total carbon and nitrogen content in roots and leaves, and total N absorption, were assayed during the cultivation. [Result] No significant differences in plant height, dry biomass, and total N content were found within the first 16 d among three treatments; however, significant differences in treatments on 24 d and 32 d were observed, the order was NO3^--N〉Gly-N〉NH4^＋-N. Significant differences were also observed between the two tomato cultivars. Chlorophyll contents in the two cultivars were significantly increased by the Gly-N treatment, root activity showed a significant decrease in NH4^＋-N treatment. Tomato leaf total carbon content was slightly affected by different N forms, however, total carbon in root and total nitrogen in root and leaf were promoted significantly by inorganic and organic N. Among those applied N forms, the increasing effects of the NH4^＋-N treatment were larger than that of the Gly-N. [Conclusion] Different N resources resulted in different physiological effects in tomatoes. Organic nitrogen （eg. Gly-N） can be a proper resource of plant N nutrition. Tomatoes of different genotypes had different responses under organic nitrogen （eg. GIy-N） supplies.