不同氮素处理对香椿一年生苗生长及光合特性的影响

Effect of Different Nitrogen Treatments on Growth and Photosynthetic Characteristics of One-year Seedling of Toona sinensis

设置0、50、100、150、200、300、400、600 mg/株8个氮处理实验,研究氮素对香椿一年生苗生长及光合特性的影响.结果表明,香椿苗高、地径及根、茎生物量和根茎生物总量随着供氮量的增加,呈现先增加后降低的趋势,且在供氮量400 mg/株时最高,其中,苗高、地径差异性显著,其他差异性不显著;香椿苗光合特性与生长表现基本契合,随供氮水平的提高,香椿叶绿素a、b及总量(a+b)先升高后降低,净光合速率、气孔导度、蒸腾速率值也均呈先扬后抑之势;供氮量400 mg/株时,净光合速率数值最高,且不同氮素处理间香椿一年生苗叶绿素含量、光合速率、蒸腾速率、胞间CO2浓度的差异性均显著,气孔导度无显著差异;综合香椿一年生苗各生长及光合指标的分析结果,400 mg/株的供氮量为香椿一年生苗苗圃培育的适宜范围.

This paper set up eight N treatments which were 0,50,100,150,200,300,400 and 600 mg per plant to study the effects of nitrogen on the growth and photosynthetic characteristics of Toona sinensis seedlings.The Results showed that the seedling height,diameter,root,shoot biomass,and total biomass of root and shoot of T.sinensis seedlings tended to increase and then decrease with the increase of nitrogen supply,and were highest when the nitrogen supply was 400 mg per plant.Among the comparative data,the differences of seedling height and diameter were significant,while the other differences were not.The photosynthetic characteristics and growth performance of T.sinensis seedlings basically coincided.With the increase of nitrogen supply,the contents of chlorophyl a,chlorophyl b and tota(l a+b)in T.sinensis increased first and then decreased,and the net photosynthetic rate,stomatal conductance and transpiration rate also increased first and then decreased.Among them,the net photosynthetic rate are highest when the nitrogen supply was 400 mg per plant,and the differences of the annual chlorophyl content,photosynthetic rate and transpiration rate of T.sinensis,in intercellular CO2 concentration among different N treatments are significant,while the stomatal conductance has no significant difference.According to the analysis of the growth and photosynthesis indexes of annual seedlings of T.sinensis,the nitrogen supply of 400 mg per plant is optimal for one-year seedling nursery cultivation.