光照强度对8种红树植物幼苗生长和生物量分配的影响

选取无瓣海桑(Sonneratia apetala Buch-Ham.)、卤蕨(Acrostichum aureum Linn.)、桐花树(Aegiceras corniculatum Blanco.)、老鼠簕(Acanthus ilicifolius Linn.)、木榄(Bruguiera gymnorrhiza Lam.)、秋茄(Kandelia candel Druce.)、银叶树(Heritiera littoralis Ait.)和黄槿(Hibiscus tiliaceus L.)为研究对象,通过遮荫控制实验,研究这8种红树植物幼苗在不同光照强度(自然光强的100%、45%、30%、10%)下的生长和生物量分配特征。结果表明:(1)遮荫对无瓣海桑幼苗相对生长速率、生物量积累、基径的增长和叶片数的增长均有显著的抑制作用;(2)桐花和老鼠簕在遮荫处理下生长状况较好,遮荫对桐花生长的影响不显著,对老鼠簕幼苗的生长则有一定的促进作用;(3)当光照强度降低时,无瓣海桑、秋茄、老鼠簕、桐花树的幼苗都对地上部分投入了更多的生物量,其中秋茄、老鼠簕和桐花树通过提高叶生物量来获取更大的光能捕获能力。研究结果表明,从对光照的生长适应角度来看,桐花、老鼠簕和卤蕨适宜种植在郁闭度较高的林下;秋茄适宜在郁闭度较低的林下种植;真红树无瓣海桑和木榄以及半红树黄槿和银叶树则不适合在林下种植。

Effects of light intensity on growth and biomass allocation of seedlings of the eight mangrove species

The characteristics of growth and biomass allocation in seedlings of eight mangrove plant species(Acrostichum aureum Linn.,Aegiceras corniculatum Blanco.,Acanthus ilicifolius Linn.,Bruguiera gymnorrhiza Lam.,Kandelia candel Druce.,Heritiera littoralis Ait.,Hibiscus tiliaceus L.)under different light intensities(100%,45%,30%,10% of full sunlight)were studied using shading control experiment.The results showed that:(1)Shading significantly inhibited the relative growth rate,biomass accumulation,basal diameter growth and leaf number accumulation of S.apetala seedlings.(2)Seedlings of A.ilicifolius and A.corniculatum grew well under shading treatments.Shading had no significant effect on the growth of A.corniculatum seedlings,but promoted the growth of A.ilicifolius seedlings.(3)With the decrease of light intensities,seedlings of S.apetala,K.candel,A.ilicifolius and A.corniculatum allocated more biomass to their aboveground growth,and among them,seedlings of the latter three species increased biomass allocation to leaves to improve the ability of light capture.The results indicate that from the perspective of growth adaptation of light intensities,A.ilicifolius,A.corniculatum and A.aureum are suitable for planting under forests with high canopy density,and K.cande can be planted under forests with low canopy density,while S.apetala,B.gymnorrhiza,H.littoralis and H.tiliaceus are not suitable for planting under forests.