Effects of Silicon Fertilizer Addition on Leaf Traits and Photosynthetic Characteristics of Schima superba Seedlings under Different Light Intensities
[Objective]To explore the response of Schima superba Gardner & Champ.seedlings to silicon fertilizer addition under different light intensities and to provide practices for improving the light adaptability and silvicultural effectiveness of S.superba seedlings.[Method]Based on one-year-old S.superba seed-lings under five different light intensity gradients(L1:76910.37±1 025.23 lx,L2:46123.75±915.26 lx,L3:31006.29±534.82 lx,L4:11695.45±485.21 lx and L5:3813.28±289.58 lx),the light intensities were close to 100％,60％,40％,15％and 5％of full light-illumination intensity.Four silicon fertilizer addition treatments(Si0:0 mg·kg-1,Si1:1 000 mg·kg-1,Si2:2000 mg·kg-1,Si3:4000 mg·kg-1)were established.The effects of light intensity and silicon fertilizer addition on the growth,leaf traits and photosynthetic physiolo-gical characteristics of S.superba seedlings were examined by measuring the seedling height,ground dia-meter growth,leaf morphology,chlorophyll fluorescence parameters,photosynthetic parameters and chlorophyll content.[Result]The results showed that:1)Compared with full light intensity,light-shading promoted seedling height growth and biomass accumulation,reduced ground diameter growth;and made leaf length-width ratio,leaf area(LA)and specific leaf area(SLA)increased significantly,and leaf dry weight(LDW)increased.At the same time,shading significantly increased the potential photochemical effi-ciency of PSⅡ(Fv/Fo),decreased the maximum photosynthetic quantum yield of PSⅡ(Fv/Fm),and signific-antly increased the net photosynthetic rate(Pn),stomatal conductance(Gs),intercellular CO2 concentra-tion(Ci)and transpiration rate(Tr),as well as the contents of chlorophyll a(Chla)and total chlorophyll(Chi).The content of chlorophyll b(Chib)increased first and then decreased along the light intensity gradi-ent.2)Compared with the control(without silicon fertilizer addition),silicon fertilizer addition significantly in-creased the growth of seedling height,ground diameter and total biomass increased significantly.The leaf length-width ratio,LA,SLA and LDW generally increased first and then decreased along the silicon fertil-izer addition gradient.Fv/Fo and Fv/Fm increased significantly.There were significant differences in Pn,Gs,Ci and Tr among treatments.The contents of Chla,Chlb and Chi increased significantly under silicon addi-tion treatments.[Conclusion]S.superba seedlings are more suitable for growth in a moderate shading light environment(11 000-46000 lx).Moderate application of silicon fertilizer(1 000-2 000 mg·kg-1)may ef-fectively alleviate the damage of photoinhibition to seedlings and improve the growth adaptability of Schi-ma superba seedlings to different light intensities.
万方数据
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