氮水平和形态配比对巴西橡胶树花药苗生长及氮代谢、光合作用的影响

采用砂培方法研究了不同供氮水平及NH4+/NO3-配比对巴西橡胶树花药苗生长、氮代谢及光合作用相关指标的影响。结果表明，随供氮水平的提高，橡胶花药苗茎秆、叶、地上部及单株总干重、植株各部位氮含量和氮积累量、叶绿素含量均相应升高，其中粗根、茎秆、叶片含氮量、单株吸氮量及叶绿素含量各处理间差异均达显著水平；株高、茎粗、细根干重、叶片光合速率先增后减，且以8 mmol/L氮水平时最大；低氮水平下细根硝酸还原酶（NR）活性较高。不同NH4+/NO3-配比试验中，纯NH4+营养下小苗各部位氮含量、氮积累量最高（除细根和叶柄氮积累量）；NH4+/NO3-为75/25时，小苗株高、茎粗、叶柄、叶片、植株地上部及株干重最大，NH4+/NO3-为50/50时，小苗细根干重、茎秆干重、叶绿素含量、光合速率最大，且显著大于纯NO3-营养处理；而NH4+/NO3- 50/50时，处理间差异不显著（除细根和茎秆N含量）；纯NO3-营养下小苗细根NR活性最高，但生长最弱。结果说明橡胶花药苗不适宜于纯NO3-环境，而适宜于纯NH4+及NH4+/NO3-混合营养，其适宜水平为8 mmol/L和NH4+/NO3-50/50。

Effects of different nitrogen levels and NH4+/NO-3 ratios on the growth,nitrogen metabolism and photosynthesis of anther-derived somatic seedlings of Hevea brasiliensis

The effects of four nitrogen(N) levels(1,4,8,and 16 mmol/L,using ammonium nitrate as the N source) and five NH+4/NO-3 ratios(100/0,75/25,50/50,25/75,and 0/100) on the growth,N metabolism and photosynthesis of anther-derived somatic seedlings of Hevea brasiliensis were studied in a sand culture experiment.The dry weight of stem,leaves,shoot and single plant,the N concentration and N uptake of the roots,stem and leaves,and the chlorophyll concentration increased correspondingly with the increasing N level.The...