亚热带地区树叶凋落物在流水和静水环境中的淋溶规律

Leaching process of leaf litter in running water and lentic water in subtropical China

为了解亚热带地区水体中树叶凋落物在分解初期的淋溶规律，比较研究了广州地区8种常见树种的树叶凋落物在静水和流水环境中淋溶量的变化。结果表明，在第1d内，8种树叶无论在静水还是流水环境下干重损失率均显著高于其他时段（P〈0．05），但不同树种在淋溶量的大小上存在差异，其中以质地柔软、革质化程度低的人面子树叶干重淋溶率最大（流水中：27．0％；静水中：24．2％）；质地坚硬、革质化程度高的竹柏树叶淋溶率最小（流水中：9．8％；静水中：8．0％）。第2d和第3d，8种树叶凋落物的干重损失率无显著差异，表明淋溶阶段趋于结束。综上结果表明，亚热带地区的树叶凋落物在静水环境和流水环境中的淋溶阶段均主要出现在第1天。

To investigate the leaching process in the prophase of leaf litter decomposition in water in subtropical region of China, we studied the leaching mass losses of leaf litter of 8 common species in Guangzhou in lentic or running water. The results showed that the rate of dry mass loss of leaf litter of all species whether in lentic water or in running water were significantly higher in the first day than in other days （P〈0.05）, but the difference of leaf species might lead to different leaching mass losses. The leaching rate of Dracontomelon duperreanum whose leaves are soft and thin-coriaceous was significantly higher than those of other species （27.0% lost in running water, 24.2% in lentic water）, and the leaching rate of Podocarpus nagi whose leaves are rigid and coriaceous was the lowest （9.8% in running water, 8.0% in lentic water）. There was no significant difference in the rate of dry mass loss in the 2nd day and 3rd day, which suggested the leaching might finish. Summarily, the leaching phase of leaf litter in subtropical zone lasted out for one day whether in lentic water or in running water.