Effects of Canopy Density and Fertilization on Leaf Growth and Photosynthetic Physiology of Erythropalum scandens

To examine the growth status and physiological properties of Erythrophalum scandens leaves under varying treatments, a two-year-old plant was selected as the research subject. A two-factor randomized block experimental design, incorporating 3 levels of canopy density and 5 types of fertilization, was employed to investigate the effects. The results showed that canopy density, fertilization type, and their interaction had a highly significant effect on most indices of E. scandens, and all levels of fertilization treatments, except for the control, were beneficial in alleviating the inhibition of photosynthesis in E. scandens under canopy conditions; under the same type of fertilization, as the canopy density level increased, the fresh weight, leaf area, specific leaf area, dry weight, chlorophyll a, carotenoids, and the overall chlorophyll a/b of E. scandens leaves gradually increased, while the content of soluble sugars and soluble proteins showed a decreasing trend; under the same canopy condition, as the content of organic fertilizer in the fertilization increased, the net photosynthetic rate(P_n), stomatal conductance(G_s), and transpiration rate(T_r) of E. scandens leaves gradually increased, and the intercellular CO₂ concentration(C_i) showed a decreasing trend; in the membership degree analysis, the L₁F₃ treatment(moderate canopy density 0.42–0.51 + compound fertilizer∶bioorganic fertilizer=1∶1)was the most comprehensively optimal, and under the same type of fertilization, the score of L₁ (moderate canopy density 0. 42–0. 51) was the best.