无机氮和氨基酸态氮处理对番茄幼苗木质部和韧皮部汁液中矿质养分的影响

Influence of Inorganic and Amino Acid Nitrogen on Mineral Nutrient Contents in Xylem and Phloem Sap of Different Tomato (Solanum lycopersicum) Cultivars

溶液培养条件下研究了番茄幼苗木质部和韧皮部汁液中氮及其它矿质养分运输对无机氮(NH4+-N、NO3--N)和氨基酸态氮(Gly-N)处理的不同响应。结果表明,不同氮素处理8d后,‘申粉918’和‘沪樱932’番茄木质部和韧皮部汁液中全氮含量表现为NH4+-N>Gly-N>NO3--N处理,而氮溢出量则以Gly-N处理的最多,其次为NH4+-N或NO3--N处理。两个品种木质部汁液中K、Ca、Mg以及‘沪樱932’木质部汁液中Cu含量表现为NO3--N>Gly-N>NH4+-N处理,而‘申粉918’中的Cu含量则表现为NO3--N>NH4+-N>Gly-N处理。两个品种木质部汁液中K、Ca、Mg、Cu、Zn、Mn溢出量均表现为NO3--N>Gly-N>NH4+-N处理;韧皮部汁液中K、Ca、Cu、Mn溢出量表现为Gly-N>NO3--N>NH4+-N处理;而其Mg、Zn溢出量则表现为NO3--N>Gly-N>NH4+-N处理,且‘沪樱932’的变化幅度较‘申粉918’的小。NH4+-N处理抑制番茄木质部养分向上运输的能力远大于Gly-N,‘申粉918’受抑制的程度更为明显。

Utilization of organic nitrogen（N）is an important aspect of plant N assimilation and has potential application in sustainable agriculture.In this study,contents and exudation rates of mineral nutrients in xylem and phloem sap were compared between two tomato cultivars（＇Shenfen 918＇ and ＇Huying 932＇）treated with nitrate（NO3^--N）,ammonium（NH4^＋-N）or glycine（Gly-N）for 8 days.For both cultivars,the N content in the xylem and phloem sap was in the order of NH4^＋-N〉 Gly-N 〉 NO3^--N,while the N exudation rate ranked with the highest in the Gly-N and followed by the NO3^--N or NH4^＋-N treatment.In the xylem sap,the highest contents of potassium（K）,calcium（Ca）,and magnesium（Mg）for both cultivars and the highest copper（Cu）content in ＇Huying 932＇ cultivar were found in the NO3^--N,and followed by the Gly-N and NH4^＋-N treatments.Although the highest Cu content in ＇Shenfen 918＇ cultivar was also recorded in the NO3^--N,the Cu content in the NH4^＋-N was higher than that in the Gly-N treatment.On the other hand,the highest zinc（Zn）and manganese（Mn）contents were found in the NH4^＋-N,and followed by the NO3^--N and Gly-N treatments,for both cultivars.The exudation rates of K,Ca,Mg,Cu,Zn and Mn in the xylem sap ranked with the highest in the NO3^--N,the lowest in the NH4^＋-N,and the Gly-N treatment in between,for both cultivars.The degree of decline in the exudation rates was larger in the NH4^＋-N than in the Gly-N treatment,and it was greater in ‘Shenfen 918＇ than in ‘Huying 932＇ cultivar.The highest exudation rates of K,Ca,Cu,and Mn in phloem sap were found in the Gly-N and followed by the NO3^--N and NH4^＋-N treatments.The order for exudation rates of Mg and Zn in phloem sap and the degrees of decline in their exudation rates were similar to the results on the xylem sap.Our results suggested that the different responses of nutrient translocation in the xylem and phloem sap to organic N supply might relate to genotypes of tomato plants.