竹类凋落叶对4种乔木树种种子萌发的影响

摘要

研究凋落叶厚度、凋落叶类型和播种位置对4种冠层乔木香樟、栲树、喜树和罗浮柿种子萌发的影响,探讨竹类凋落叶对森林更新影响的程度.结果表明:凋落叶上方和下方播种对4种乔木树种种子的最终萌发率和幼苗发生率均产生显著影响,而凋落叶厚度和凋落叶类型对4个树种种子萌发状况的影响不同.播种在凋落叶上方的种子萌发率都很低甚至萌发失败,而播种在凋落叶下方的种子萌发率较高.竹类凋落叶下方种子的萌发速率高于乔木凋落叶下方种子,但是竹类凋落叶下方的出苗速率和最终出苗率低于乔木凋落叶下方.研究表明:竹类凋落叶覆盖不利于乔木幼苗存活,且对落叶树种的影响更明显,从而会降低森林的物种多样性,进而影响森林的结构和动态.%Effects of litter depth and type, and seed - sowing position on the germination of four canopy species, Cinnamomum camphora , Castanopsis fargesii, Camptotheca acuminate and Diospyros morrisiana , were investigated to study influences of bamboo leaf litter on forest regeneration. The results showed that the seed-sowing position had a significant influence on the germination and seedling emergence of all the species. Effects of litter depth and litter type on the germination varied with trees species. Seeds sown on the litter surface had much lower germination rate or failed to germination. Seeds under litter cover had higher germination rate and shorter germination time. The germination rate was higher, but emergence rate and finally seedling emergence rate were lower under the bamboo leaf litter compared with under canopy trees litters. This study showed that bamboo leaf litter cover could increase seedling mortality and significantly influence the seedling mortality rate of deciduous. Bamboo leaf litter would reduce forest species diversity and consequently affect forest structure and dynamics of forest succession.