种子大小和枯落物覆盖对黑松种子萌发和幼苗生长的影响

2017年5月10日,将烟台沿海防护林内20～30年生黑松Pinus thunbergii母树的种子分为大粒、中粒和小粒播于花盆中,研究枯落物覆盖厚度(1 cm,2 cm,3 cm,4 cm)对种子萌发和幼苗生长的影响,以阐明沿海黑松防护林幼苗建立的机制。结果表明:种子大小对发芽率、发芽指数有着极显著影响(P<0.01),对平均发芽时间、活力指数没有显著影响。大粒种子比中小粒种子有着低的发芽率和发芽指数。在生物量分配和根系特征上种子大小没有显著影响,但对幼苗高度和地径有显著的影响(P<0.05),都是大粒和中粒种子大于小粒种子。枯落物覆盖厚度对于种子萌发有显著影响(P<0.05),发芽率、发芽指数、活力指数都随枯落物厚度的增加而增加,平均发芽时间则逐渐降低;但对幼苗生物量、生物量分配和根系特征无显著影响。相关分析表明,苗高和地径与发芽指标、幼苗生物量分配相关性不显著,但与比根长和比根表面积成显著正相关。因此,种子大小和枯落物覆盖厚度是影响沿海黑松防护林天然更新的重要因素。

Effect of Seed Size and Litter Thickness on Germination and Seedling Growth of Pinus thunbergii

Cones were harvested from 20-30-year Pinus thunbergii at coastal protection forest in Yantai of Shandong province in September of 2016. The seeds were divided into large, medium and small size and sown in pots covered with different litter thickness (1, 2, 3 and 4 cm). The results showed that seed size had significant effect on germination rate and germination index, but no significant effect on average germination time and vigor index. Large seeds had lower germination rate and index than medium and small ones. Seed size had no significant effect on biomass allocation and root growth, but had significant positive effect on height and ground diameter growth of seedlings. Germination rate, germination index and vigor index had positive relation with litter thickness, while the average germination time had negative one. Litter thickness had no great effect on seedling biomass, biomass allocation and root growth. Correlation analysis showed that seedling height and ground diameter had no significant relation with germination index and seedling biomass allocation, but had evident positive relation with specific root length and specific root area.