Effects of submergence in water on seed germination and vigor of the Copaifera lucens(Fabaceae) seedlings

We analyzed the tolerance of Copaifera lucens seeds to sub- mersion in water to assess the use of this species for direct seeding in riparian forest restoration programs. Seeds were submerged in water for 2, 4, 8, 16 and 32 days or not submerged （control = 0 days of submer- gence）. For the control and at the end of each period of submersion, germination and seedling vigor tests were carried out. For germination tests, seeds were sown in plastic pots containing sand and kept in labora- tory conditions. The percentage of seed germination, the germination rate and the average germination time were analyzed. For seedlings, total biomass, leaf area, leaf mass per area and leaf area ratio were analyzed. Submersion time drastically affected the dissolved oxygen content and seed germination. Between 4 and 8 days of submersion there was a de- crease from 83.8% to 15.6% in the germination percentage. No seed germination occurred after 16 days of submersion. Although there was a significant decrease in the percentage of seed germination between 4 and 8 days of submersion, seedling vigor was not affected. Seeds of this species were partially tolerant to submersion in water, suggesting that C. lucens is a promising species for direct seeding in riparian forest restora- tion projects.

两种热带树种在弱光条件下的生长和表型可塑性

根据耐荫性筛选热带雨林树种,对于在次生林富集区域中更有效地管理具有经济意义的本土树种非常重要。本研究旨在确定全株的光补偿点,比较弱光条件下Cariniana legalis和Gallesia integrifolia幼苗生长和碳分配有关的表型可塑性。实验所用幼苗在5种光合有效辐射条件下(0.02、1.1、2.3、4.5和5.9 mol photons m^(−2)day^(−1))培养77天,设置3个重复,并分析了生长和碳分配变量指标。结果显示,在1.1 mol photons m^(−2)day^(−1)条件下,C.legalis的生长速率高于G.integrifolia,而在5.9 mol photons m^(−2)day^(−1)条件下,C.legalis的生长速率低于G.integrifolia。不同物种间的光补偿点差异显著。根据耐阴分类标准对这两种热带树种进行分类,我们的研究结果表明,C.legalis相对较低的光补偿点和表型可塑性与生长速率有关,比G.integrifolia具有更强的耐荫性。从实际的角度来看,我们证明了两种树种之间生长和光合有效辐射变化的不同关系可以成为在森林丰富工程中比较和选择种植树种的可行工具。