氮素处理对2种丁香的生长和光合特性的影响1）

研究了不同氮素水平和氮素形态比例对紫丁香（ Syringa oblata）和小叶丁香（ Sytinga microphylla）的生长和光合响应曲线特性的影响。结果表明：当m（铵态氮）∶m（硝态氮）＝2∶2时，紫丁香和小叶丁香的最佳氮素营养用量分别为30、40 mmol· L－1，此时2种丁香的株高增量、地径增量、最大光合速率、表观量子效率，暗呼吸均达到最大值，与对照组差异显著（P＜0．05）；当氮素水平为20 mmol· L－1时，紫丁香和小叶丁香的最适铵态氮硝态氮质量比分别为1∶3和2∶2。从2种丁香的生长量看，氮素形态对紫丁香的影响不大，但小叶丁香更偏好于硝态氮。

Effect of Nitrogen Treatments on the Growth and Photosynthetic Characteristics of Two Cloves

We studied on the effect of growth and photosynthetic response curve characteristics of Syringa oblata and Sytinga mi-crophylla with different nitrogen levels and nitrogen form ratios .When the NH+4 N/O -3 ratio was 2∶2, the optimal amount of nitrogen nutrition for Syringaoblata and Syit ngamicrophylla were 30 and 40 mmol·L -1, respectively.The plant height in-crement, diameter increment , the maximum photosynthetic efficiency , apparent quantum efficiency and dark respiration reached the maximum , significantly different from the control groups .When the nitrogen level was at 20 mmol· L-1 , the optimal proportion of NH+4/NO-3 ratios for these two plants were 1∶3 and 2∶2, respectively.But for the growth increment , N form had little effect on Syringaoblata, but, Sytingamicrophylla preferred to NO-3 .