苗期杨树生长和光合特征在不同水分梯度和施肥下 的比较分析.

In order to improve the efficiency of water and fertilizer, and guide the scientific watering and fertilization of the poplar, using Populus deltoides Bartr. Huashi 2 as the material, the growth and photosynthetic characteristics were compared and analyzed in different water gradient and fertilizer amount. The two-factor analysis of variance of water and fertilization showed significant difference in seedling height and ground diameter between different soil water (P<0.05), significant difference in ground diameter between different fertilizer amount (P<0.05), but no significant difference in seedling height. The growth of A4B4 was the worst, and the growth of A2B2 was the best. No matter different fertilizer amount or soil water, the numbers of leaves were significantly different (P<0.05), the numbers of leaves in A4B1 were the least, the mean value was 17.67, while the numbers of leaves in A1B2 were the largest, with an average value of 39.00. It was found that the treatments with lower chlorophyll content were mainly those with less fertilizer amount (B4), while the treatments with higher chlorophyll content were mainly those with higher fertilizer amount (B1,B2). The maximum light saturation point (PLS) was A1B1(1961.59 μmol·m-2·s-1), and the maximum net photosynthetic rate (Pnmax) of A2B1 was the highest (24.75 μmol·m-2·s-1). There was no significant difference and regularity about the light compensation point (PLC) and dark respiration rate (Rd). To improve the quality of poplar seedlings, water and fertilizer were not the more the better. Keeping soil water as 80%-85% of field water holding capacity and applying compound fertilizer 15 g with one plant from May to July could effectively increase the number of leaves, enhance the ability of leaf to adapt to strong light and photosynthetic potential, and enhance the growth advantage. [ABSTRACT FROM AUTHOR]