喀斯特阔叶树种不同特征枯落叶的持水性能

为了探明不同树种枯落叶的持水性能,为喀斯特地区造林提供理论依据,采用实地调查法研究了喀斯特50种阔叶树种不同特征枯落叶的持水性能.结果表明:1)除纸质叶片外,其余特征枯落叶的最大持水率均以半分解状态大于未分解状态,纸质、有表皮毛叶片未分解与半分解状态最大持水率的差异不显著,革质、无表皮毛则差异显著.2)平均最大持水率大小顺序为纸质叶片(340.77％)＞有表皮毛(292.27％)＞无表皮毛(249.73％)＞革质(229.46％).3)未分解与半分解枯落叶持水量在0～2 h增加最快,2～6 h增加缓慢,6h后趋于稳定,持水量与浸水时间存在明显的对数函数关系.4)枯落叶吸水速率在前0.25h最大,1h左右时明显减缓,4h后趋于稳定,与浸水时间存在幂函数关系.5)枯落叶最大持水率大于300％的多为纸质和具有柔毛的枯落叶,小于200％的几乎全为革质枯落叶.结论:在喀斯特石漠化地区植被恢复过程中,可以优先选择叶片为纸质和具有柔毛的树种进行种植,以充分发挥其持水功能.

Characteristics of Water-holding Properties of Leaf Litters of Deciduous Tree Species in Karst Region

To know about the water-holding properties of leaf litters of different tree species and provide a theoretical reference for forestation in karst region,a field investigation was conducted to study the water-holding properties of leaf litters of 50 tree species.The results showed that: 1) The maximum water-holding ratio of the semi-decomposed leaf litters(except papery leaves) was higher than that of undecomposed ones.The water-holding ratios did not present much significant differences among papery leaf litters,semi-decomposed leaf litters and undecomposed leaf litters with epidermal hair.but the difference was significant between leathery ones and without trichomes ones.2) The order of the maximum water-holding ratio was papery(340.77%)> with trichomes(292.27%)> without trichomes(249.73%)> leathery(229.46%).3) For both the undecomposed and semi-decomposed leaf litters,the water-holding capacity increased much quickly in 0~2 h,but increased slowly in 2~6 h and become stable six hours later.The relationship between water-holding capacity and time showed logarithmic curve.4) The water-holding ratios of the leaf litters was up to maximum at 0.25 h,and it slowed down significantly about one hour later,and stabilized after four hours,the change of the water-holding ratio with time presented a power function curve.5)The maximum water-holding ratio of leaf litters which more than 300% were papery and without trichomes,less than 200% of the leaf litters were almost leathery.So it was concluded that the tree species with papery leaves or trichomes were optimum to be planted in karst region during the process of revegetation for their fully developed water-holding capacity.