广西植物2016，Vol.36Issue(6)：713-719,734,8.DOI:10.11931/guihaia.gxzw201504034
元阳梯田水源区旱冬瓜水分来源
Water utilization sources of Alnus nepalensis in the water source area of Yuanyang terrace
摘要
Abstract
Alnus nepalensis is one of dominant tree species in the water source area of Yuanyang terrace. As a fast-grow-ing tree species, it has been the important firewood forests and economic forests to local residents. Water constrains its vegetation growth and geographic distribution. In SPAC system, forest vegetation as the main body of forest ecological system and dominate the redistribution of water resources, its absorption of moisture and water utilization change will di-rectly affect the water cycle of forest ecosystem. We conducted this study from May to Novernber of 2014, with accumula-tive rainfall 1 262 mm. The groundwater in the study area of δ D values ranged from -71‰ to -53‰,δ18 O values ranged from -10.6‰ to -7.0‰, less affected by environmental factors, basically remained stable; In this paper, A. nepalensis roots absorbed water from all the water sources and transport in the xylem water did not occur isotopic fractionation char-acteristic. We combined with the soil moisture content, the water utilization sources of A. nepalensis mainly came from 40 cm soil layer in dry season and 0-60 cm in rainy season to analyze the A. nepalensis water utilization strategies by com-parison with the δ D values of xylem water and soil water, with hydrogen and oxygen stable isotope techniques. The re-sults of quantify analysis its water sources with multivariate linear mixed model of Isosource software showed that A. ne-palensis had a wide distribution of water source, both the soil water and groundwater had contribution, 0-60 cm soil wa-ter was important water sources in the rainy season, and after raining most of the water source from 0-10 cm soil mois-ture, the proportion was 66%-73%;Other main water source from 40-60 cm soil water, contribution rate was as high as 73%;In the dry season, A. nepalensis utilize groundwater proportion was higher, the proportion was 18%-68%. Water constrained vegetation growth and geographic distribution. In SPAC system, forest vegetation as the main body of forest ecological system and dominate the redistribution of water resources, its absorption of moisture and water utilization change would directly affect the water cycle of forest ecosystem. This analysis on A. nepalensis water utilization sources from soil water and shallow ground water in different time scales, provides a basic model water utilization of dominant tree species in Yuanyang terrace, more accurated understanding of the water source of dominant tree species in different forest types, and necessary theoretical basis for management the terrace forest ecosystem and develop sustainable terrace in Yuanyang.关键词
元阳梯田/旱冬瓜/稳定氢氧同位素/土壤水/水分来源Key words
Yuanyang terrace/Alnus nepalensis/hydrogen and oxygen isotope/soil water/water utilization sources分类
生物学引用本文复制引用
王卓娟,宋维峰,吴锦奎,张小娟..元阳梯田水源区旱冬瓜水分来源[J].广西植物,2016,36(6):713-719,734,8.基金项目
国家自然科学基金(41371066)[Supported by the National Natural Science Foundation of China(41371066)]。 （41371066）
