摘要
通过测定大柴旦与都兰地区猪毛菜木质部水分及其不同潜在水源的稳定性氢氧同位素值,利用多源线性混合模型分析不同水分来源对猪毛菜的贡献率.研究结果表明:大柴旦地区大气降水线为y=7.565x+4.796(R2=0.908),都兰地区大气降水线为y=6.005x-7.856(R2=0.7391),说明两个地区都存在较强的蒸发作用.但是,都兰地区较大柴旦风速大,温度高,雨水蒸发速度快,造成雨水δ18O偏高,形成比大柴旦地区斜率更小的当地大气降水线.大柴旦和都兰地区的猪毛菜,在两个样地的用水策略上存在显著差异.在降水较少的大柴旦地区,猪毛菜以土壤水为主要水源.在降水较多的都兰地区,则以降水为主要水源.就其对土壤水的使用情况来看,大柴旦的猪毛菜多利用深层土壤水,而都兰地区的猪毛菜却对表层土壤水利用比例较大.两地猪毛菜在生长季的不同时期都存在对利用水源的转换现象.为适应不同地区降水量的变化,猪毛菜根据不同水源调节利用比例.降水格局的改变将导致猪毛菜的水分利用策略发生适应性的变化.
In arid and semiarid regions,precipitation is the most important water source for plants. The objective of this study is to determine the proportions of different water sources drawn by Salsola abrotanoides,examine the consistence of this proportion for Salsola abrotanoides during the growth season,investigate the water sources of Salsola abrotanoides along a precipitation gradient in Qaidam Basin. Salsola abrotanoides was selected to test the stem water δ18O and δD using Picarro L-2130 i and Finnegan MAT-253. δ18O and δD was also tested for different available water resources including river water,soil water（ profiled as 0 ～ 10 cm,10 ～ 30 cm,30 ～50 cm,50 ～ 70 cm,70 ～ 90 cm） and effective precipitation at same time,which were sampled every 15 days from June to September in 2010 in Da Qaidam and Dulan areas. The Multi-source mixed linear model was used to analyze the contribution of different water sources to Salsola abrotanoides. The Da Qaidam area local meteoric water line（ LMWL） equation is y = 7. 656 x ＋ 4. 796（ R2= 0. 908）; The Dulan area local meteoric water line（ LMWL） equation is y = 6. 005x- 7. 856（ R2= 0. 7391）. Both Da Qaidam and Dulan areas have strong evaporation. The wind speed in Dulan area is larger than that in Da Qaidam area,and the temperature was higher also.Vapor of the precipitation make the rake ratio and Ex d lower. Salsola abrotanoides can adjust their capabilities for up-take from different water sources and other physiological properties with variation in natural precipitation,but the strategies are various. At Da Qaidam site,where annual precipitation is low,Salsola abrotanoides obtains the highest proportion of water from soil water. However,the Salsola abrotanoides at Dulan site,where annual precipitation is higher,depended mainly on effective precipitation. Salsola abrotanoides at Da Qaidam site mostly uses soil water from deep layer. While at Dulan site,Salsola abrotanoides absorbs water from shallowsoil more evenly. Both Salsola abrotanoides at Da Qaidam and Dulan areas change the absorbing proportion of different water sources during growth season. These results suggest that Salsola abrotanoides can adjust their capability for up-take from different water sources and other physiological properties with variation along a precipitation gradient. Precipitation pattern change will lead the Salsola abrotanoides ＇ water use strategies adaptive change.
出处
《冰川冻土》
CSCD
北大核心
2015年第5期1396-1405,共10页
Journal of Glaciology and Geocryology
基金
国家自然科学基金项目(40971118)
河北省自然地理学省级重点学科资助项目资助
关键词
猪毛菜
降水差异
水分来源
稳定氢氧同位素
Salsola abrotanoides
precipitation difference
water sources
stable hydrogen and oxygen isotope
