摘要
[目的]探究木荷幼苗在不同光照强度下对硅肥添加的响应,为提高木荷幼苗的光适应性与造林成效提供指导.[方法]以一年生的木荷幼苗为研究对象,设置5种不同的光照强度梯度(L1:76 910.37±1 025.23 lx、L2:46 123.75±915.26 lx、L3:31 006.29±534.82 lx、L4:11 695.45±485.21 lx 和 L5:3 813.28±289.58 lx),各光照强度接近于全光照的100％、60％、40％、15％与5％,以及4个硅肥添加处理(Si0:0mg·kg-1,Si1:1 000 mg·kg-1,Si2:2 000 mg·kg-1,Si3:4 000 mg·kg-1).通过测定木荷幼苗苗高、地径增长量、叶片形态指标、叶绿素荧光参数、光合参数及叶绿素含量,分析光照强度和硅肥添加对木荷幼苗的生长、叶片性状及光合生理特征的影响.[结果]研究表明:1)与全光照相比,遮荫促进了幼苗的苗高生长和生物量积累,降低了地径增长量;叶长宽比、叶面积(LA)、和比叶面积(SLA)显著增加,叶干质量(LDW)增加.同时,遮荫显著增加了幼苗的PSⅡ潜在光化学效率(Fv/Fo),降低了 PSⅡ最大光合量子产量(Fv/Fm),并且显著提高了净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)和蒸腾速率(Tr),以及木荷叶绿素a(Chla)和总叶绿素(Chl)含量,叶绿素b(Chlb)沿光强梯度先增后减.2)与未施硅肥相比,施用硅肥后,苗高增长量、地径增长量和总生物量显著增加;叶长宽比、LA、SLA和LDW总体沿硅肥添加梯度先上升后下降.Fv/Fo、Fv/Fm均显著上升;各处理间Pn、Gs、Ci、Tr差异显著;Chla、Chlb和Chl含量显著上升.[结论]木荷幼苗更适合在适度遮荫的光环境下(11 000～46 000 lx)生长,适度的施用硅肥(1 000～2 000 mg·kg-1)可有效缓解光抑制对幼苗的损伤,提高木荷幼苗对不同光照强度的生长适应性.
Abstract
[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.
维普
万方数据