不同硝铵比对霞多丽葡萄幼苗生长和氮素营养的影响

采用沙培试验,设置了等氮条件下5种不同硝铵比营养液处理,探讨了氮形态对霞多丽葡萄幼苗生长和氮素营养的影响。结果表明,霞多丽幼苗的生长量以硝铵比70/30时最大,全铵营养时最低;植株根系氮的平均吸收量在硝铵比为70/30时为最大值,达到70.89%,全铵营养时为最低值;叶片中的氮浓度和总氮量以全硝营养最大,全铵营养最低,后者仅是全硝营养的61.8%和19.46%。霞多丽幼苗根系内NH4+-N浓度与营养液中NH4+-N的浓度成极显著正相关(r=0.9805),且当铵态氮比例超过30%时根系中NH4+浓度显著增加。叶片中硝酸还原酶的活性以硝铵比70/30最高,当铵态氮比例大于30%,再继续增加铵态氮的比例时,显著抑制了叶片中硝酸还原酶的活性;而对根的硝酸还原酶活性无明显影响。试验证明,硝铵比70/30是霞多丽较适宜的氮素形态配比,较高比例的铵态氮增加了植株器官中NH4+的浓度,抑制了霞多丽幼苗的生长及对氮素的吸收积累。

Effects of NO_3~--N/NH_4~+-N ratios on Chardonnay grape seedling growth and nitrogen nutrition

A sand culture experiment was conducted to determine the effect of different nitrogen supply forms on growth and nitrogen nutrition of Chardonnay grape seedling. Five NO₃^--N/NH₄⁺-N ratios were set up as 100/0, 70/30, 50/50, 30/70, and 0/100 with total nitrogen being equal amount. The results indicated that Chardonnay grape seedling fertilized with NO₃^--N/NH₄⁺-N ratios for 70/30 had the highest biomass and root nitrogen absorption (70.89%); While Chardonnay grape seedling had the lowest biomass when fertilized with ammonium as the sole nitrogen source. The Chardonnay grape seedling fertilized with NO₃^--N/NH₄⁺-N ratios for 100/0 had the highest amount of nitrogen concentration and total N in leaf, while Chardonnay grape seedling fertilized with NO₃^--N/NH₄⁺-N ratios for 0/100 had the lowest, which were 61.8% and 19.46% of fertilized with NO₃^--N/NH₄⁺-N ratios for 100/0, respectively. The concentration of NH₄⁺-N in root significantly correlated to the nutrient solution (r=0.9805), and the concentration of NH₄⁺-N in root increased significantly when the proportion of ammonium nitrogen was higher than 30%. Leaf nitrate reductase activity was the highest when fertilized with NO₃^--N/NH₄⁺-N ratios for 70/30. The leaf nitrate reductase activity was impaired significantly when the proportion of ammonium nitrogen was higher than 30%, but the root nitrate reductase activity was not influenced. The experiment proved that NO₃^--N/NH₄⁺-N ratios for 70/30 was appropriate for the Chardonnay grape seedling, and a lower proportion of the NO₃^--N/NH₄⁺-N ratios increased the concentration of NH₄⁺ in Chardonnay grape seedling organs, consequently inhibited nitrogen absorption and the biomass accumulation.