Comparison of Growth and Photosynthetic Physiological Characteristics of Phoebe zhennan Saplings in Three Soil Conditions

In order to explore the differences of growth and photosynthetic characteristics of Phoebe zhennan saplings in three types of soil conditions (broad-leaved forest humus soil (HS), purple soil (PS), alluvial soil (AS)), 2-years-old Phoebe zhennan saplings were taken as study material, which were planted in three types of soil conditions and the saplings morphology and photosynthetic indicators were determined in May, July and October. The results showed that: (1) Phoebe zhennan saplings planted in HS had the best growth, with more growth in plant height and ground diameter, which was obviously higher than that in PS and AS, but there was no obvious difference in morphological growth between the latter two saplings; (2) The saplings planted in HS had the highest levels of chlorophyll a(Chl a), chlorophyll b(Chl b) and carotenoids (Car) content, and the overall leaf pigment content was HS > PS > AS; (3) The overall performance of net photosynthetic rate (P_n), stomatal conductance (G_s) and transpiration rate (T_r) of saplings was HS > PS > AS; (4) The light saturation point (LSP) and CO₂ saturation point (CSP) of saplings in HS were higher than those of PS and AS, while the light compensation point (LCP) and CO₂ compensation point (CCP) were lower than those of PS and AS, indicating that saplings planted in HS had higher photosynthetic efficiency and could accumulat more organic matter. The research showed that Phoebe zhennan saplings grown best in forest humus soil (HS), followed by purple soil (PS), and alluvial soil (AS) was the worse. In practice, it is necessary to avoid planting on alluvial soil with heavy viscosity, low porosity and poor ventilation, unless there is special need.