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

To investigate the effects of canopy density and fertilization on the growth and photosynthetic physiology of Erythrophalum scandens, a two-year-old plant was used as the research subject. A two-factor random block experimental design with three levels of canopy density and five types of fertilization was employed to explore the growth status and physiological characteristics of E. scandens leaves under different treatments. The results showed that: Canopy density, fertilization type, and their interaction had a highly significant effect on most indices of Erythrophalum scandens(P < 0. 01), and all levels of fertilization treatments, except for the control, were beneficial in alleviating the inhibition of photosynthesis in Erythrophalum 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 Erythrophalum 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 Erythrophalum scandens leaves gradually increased, and the intercellular CO₂ concentration(C_i) showed a decreasing trend. In the membership degree analysis, the L₁F₃ treatmentmedium(canopy density 0.420.51 + compound fertilizerbio-organic fertilizer=1∶1)was the most comprehensively optimal, and under the same type of fertilization, the score of L₁ medium(canopy density 0. 42～0. 51) was the best. The study indicates that reasonable fertilization under medium canopy density conditions can promote the growth of Erythrophalum scandens leaves, improve photosynthetic physiology, and enhance the photosynthetic capacity of seedlings.