干旱死亡叶片与自然凋落叶化学性质对比研究

Comparison of Chemical Traits between Drought-dead and Natural Litter Leaves

摘要:

为了解干旱死亡叶片与自然凋落叶化学性质的差异性，对云南元江干热河谷5种植物（鞍叶羊蹄甲、白皮乌口树、灰毛浆果楝、细基丸和九里香）干旱死亡叶片和自然凋落叶化学性质进行比较分析。结果表明，干旱死亡叶片和自然凋落叶在碳和养分化学特性上表现出较大变异，且不同树种间存在极显著差异（P<0.001）。与自然凋落叶相比，干旱死亡叶片具有较高的可溶性碳、C/N比和Mg含量，而木质素、半纤维素和N含量则较低。干旱死亡叶片与自然凋落叶间的碳（R²=0.56，P< 0.01）、纤维素（R²=0.52，P<0.01）、半纤维素（R²=0.85，P<0.001）、单宁（R²=0.99，P<0.001）、木质素/N （R²=0.60，P<0.01）、C/N （R²=0.64，P<0.001）和氮含量（R²=0.85，P<0.001）呈显著正相关。因此，可根据自然凋落叶化学性质预测未来极端干旱条件下干旱死亡叶片的化学性质。

关键词:干旱;干热河谷;凋落物;化学性质

Abstract:

To understand the difference in chemical properties between drought-dead and natural litter leaves, the chemistry traits in leaves of five species in Yuanjiang Savanna Ecosystem Research Station, such as Bauhinia brachycarpa, Tarenna depauperate, Cipadessa baccifera, Polyalthia cerasoides and Rubus pungens, were studied. The results showed that the chemical characteristics of carbon and nutrients had great variation between drought-dead and natural litter leaves, and there were very significant differences among these tree species (P<0.001). Compared with natural litter leaves, drought-dead leaves had high dissolved organic carbon, C/N and magnesium, but the concentration of lignin, hemicellulose and nitrogen was low. Furthermore, the chemical traits of drought-dead leaves had positive correlation with nature litter leaves, such as the concentration of carbon (R²=0.56,P<0.01), cellulose (R²=0.52, P<0.01), hemicellulose (R²=0.85, P<0.001), tannin (R²=0.99,P<0.001), lignin/N (R²=0.60,P<0.01), C/N (R²=0.64,P<0.001) and nitrogen (R²=0.85, P<0.001). Therefore, according to the chemical properties of natural litters, the chemical properties of drought-dead leaves under extreme drought conditions could be predicted in the future.

Key words:Drought;Dry-hot valley;Litter-fall;Chemical property