遮荫和施肥对油丹幼苗光合作用的影响

利用LI-6400便携式光合仪测定1年生油丹幼苗在不同遮荫条件及施肥处理下的光合特性，旨在探讨油丹对光环境变化的生理响应及其适应机制。结果表明：在全光照条件下，强光容易灼伤幼苗叶片，不利于其光合作用。在不同光照强度下，幼苗叶片的净光合速率表现为1层遮阳网遮荫处理>2层遮阳网遮荫处理>全光照处理。最大净光合效率出现在1层遮阳网遮荫处理，为4.03 μmol/（m²·s），最大光饱和点、光补偿点和暗呼吸率最高均出现在全光照处理，但随着遮荫程度的增强而下降。1层遮阳网遮荫处理的最大净光合速率与1层遮阳网遮荫组+施肥的差异不显著，但光饱和点、光补偿点、暗呼吸率和表光量子效率均有一定程度提高。总体来看，油丹幼苗为喜光，半耐荫植物；1层遮阳网遮荫有利于提高油丹幼苗对光能的捕获能力，提高光合作用，从而促进其生长；短期内，施复合肥在一定程度上提高了光合参数指标，但其光合效率未出现明显变化。

Effects of Shading and Fertilization on Photosynthesis of Alseodaphne Hainanensis Seedlings

The LI-6400 portable photosynthetic apparatus was used to determine the photosynthetic characteristics of 1-year-old Alseodaphne hainanensis under different shading conditions and fertilization treatments. The purpose was to investigate the physiological response of A. hainanensis to light environment changes and its adaptation mechanism. Results show that under full light conditions, strong light easily burn the leaves of seedlings, which is not conducive to photosynthesis. Under different light intensities, Pn rate of seedling leaves is characterized by 1 layer shading net shading treatment > 2 layers shading net shading treatment > full light treatment. Pn max appears in the shading treatment of 1 layer of shading net, which is 4.03 μmol/(m2·s). LSP, LCP and Rd all appear in the full light treatment, but decrease with the increase of shading. The difference of Pn max between 1 layer shading net shading treatment and the 1 layer shading net shading group + fertilization is not significant, but LSP, LCP, Rd and AQY are improved to some extent. In general, A. hainanensis seedlings are hi-light and semi-shade-resistant plants. One layer shading net shading is beneficial to improve the ability of A. hainanensis seedlings to capture light energy, improve photosynthesis and promote its growth. In the short term, the application of compound fertilizer increase the photosynthetic parameters to a certain extent, but its photosynthetic efficiency do not change significantly.