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作 者 ：罗雪华 邹碧霞 吴菊群 杨俐苹

期 刊 ：植物营养与肥料学报 2011年 17卷 3期 页码：693-701

关键词：巴西橡胶树；花药体细胞组培苗；氮素水平；NH4+/NO3-配比；氮代谢；光合作用；

Keywords:Hevea Brasiliensis, anther-derived somatic seedling, nitrogen level, NH4+/NO3- ratio, Nitrogen metabolism,

摘 要 ：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。

Abstract:The effects of four nitrogen (N) levels (1, 4, 8, and 16 mmol/L, using ammonium nitrate as the N source) and five NH4+/NO3- 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 N concentration of the coarse roots, stem and leaves, N uptake by the plant, and the concentrations of chlorophyll a, chlorophyll b and total chlorophyll all differed significantly between treatments. The plant height, stem diameter, dry weight of fine roots and net photosynthetic rate of leaves increased with N level from 1 to 8 mmol/L, but decreased at 16 mmol/L. The nitrate reductase activity of fine roots was highest at the lowest N level. With regard to the effects of NH4+/NO3- ratio, the N concentration and N uptake in different parts of seedlings were highest when grown exclusively with NH4+ nutrition (except N uptake of fine roots and petioles); plant height, stem diameter, and the dry weights of the petioles, leaves, shoot and plant were highest in the 75/25 NH4+/NO3- treatment; the dry weight of the fine roots and stem, the chlorophyll concentration and the net leaf photosynthetic rate were highest in the 50/50 NH4+/NO3- treatment, and all were significantly higher than those of seedlings grown exclusively with NO3- nutrition but were not significantly different from those of the treatments with >50/50 NH4+/NO3- ratios except the N concentration of the fine roots and stem. Nitrate reductase activity of fine roots was highest with NO3- nutrition, but growth of the seedlings was weakest in this treatment. The results indicated that growth of the anther-derived somatic seedlings of Hevea brasiliensis was superior with NH4+ alone or combined NH4+/NO3- nutrition rather than NO3- nutrition alone, and the optimal N level was 8 mmol/L with a NH4+/NO3- ratio exceeding 50/50.

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