水分条件对干热河谷锥连栎种子萌发及幼苗早期生长的影响

Effects of Water Supply on Seed Germination and Early Seedling Growth of Quercus franchetii

摘要:

对锥连栎(Quercus franchetii Skan)在4种施水量下的种子萌发、幼苗早期生长形态及生物量分配的响应特征进行了研究。结果表明，施水量对锥连栎的种子萌发过程具有显著影响。随着施水量增加，其种子萌发率、萌发指数以及萌发时间和萌发持续时间均呈明显的上升趋势，而萌发时滞和萌发速率系数呈下降趋势。锥连栎幼苗早期生长对施水量的适应幅度较大，每次施水4～12 mm时，幼苗均能存活，但生长状况存在明显差异，随着施水量的减少，幼苗生长和生物量的积累速度均出现显著减缓。同时，施水量对锥连栎幼苗生物量分配具有显著影响，随着施水量增加，幼苗根冠比呈显著下降趋势，表明在生物量分配上锥连栎幼苗具有极大的可塑性，施水量减少时，光合产物将向地下部分迁移，增加根冠比。

Abstract:

The effects of water supply on seed germination, seedling morphology, and biomass allocation of Quercus franchetii were studied. The results showed that water supply affected significantly the seed germination of Q. franchetii. With increment of water supply, the germination rate, germination index, germination time, and germination duration of seeds increased, but germination time lag and coefficient of germination rate decreased. All of seedlings could survive under water supply of 4-12 mm per times. However, the accruements of seedling growth and biomass accumulation rate of Q. franchetii reduced with decreasing water supply. Meantime, water supply level had significant effects on biomass allocation of seedlings. The ratio of root-to-shoot of seedlings declined substantially with increment of water supply. Under low water supply, seedlings could transport photosynthates from leaves to belowground for increasing root-to-shoot ratio.