摘要
选取加杨、刺槐、白榆、沙棘和榛木５个树种，测定一年生小枝的导水率和水势，绘制出各树种的脆弱曲线。结果表明，这几个树种一年生枝木质部栓塞脆弱性的种间差异明显，其中加杨和沙棘最为脆弱，其次为刺槐、白榆和榛木。这种种间差异可能与导管壁的厚度和导管间纹孔膜上纹孔口的长径有关。耐旱树种并非对木质部空穴或栓塞的抵抗能力就强；植物遭遇水分胁迫时，在一定水势范围内，木质部栓塞降低导水率从而可减少水分丧失，这可能是树种适应干旱条件的方式之一。脆弱曲线可以提供有关植物生理生态行为的信息。
Five drought-resistent tree species: Populus canadensis Moench., Robinia pseudoacacia Linn. ,Ulmus pumila Linn., Hippophae rhamnoides Linn.and Corylus heterophylla Fisch.on the campus of Northwest Forestry College were selected and the hydraulic conductiyity of one-year-old twigs were measrued by the “flushing methed”,and water potential was measured using a pressure chamber.The “vulnerability curves”of each tree species were also ploted.The result showed that Populus canadensis Moench .and Hippophae rhamnoides Linn.were more vulnerable than the orthers,among the 5 species there were significant differences in the vulnerability,which could be accounted for by differences in the thickness of conduit wall and the diameters of pit-mambranes pores.Moreover,drought-resistent tree species could be vulnerable to xylem embolism,in a certain range of xylem water potential,xylem embolism decreased the hydraulic conductivity of xylem and limited water loss,this might be one of drought-resistence ways.Vulnerability curve could provide information on ecophysiological action of trees.The practical value of vulnerability curve and the relationship between drought-resistence and vulnerability are also discussed.
出处
《西北林学院学报》
CSCD
北大核心
1997年第2期1-6,共6页
Journal of Northwest Forestry University
基金
国家自然科学基金
国家教委留学回国人员资助
关键词
导水率
脆弱曲线
木质部栓塞
耐旱性
树木
hydraulic conductivity
vulnerability curve
xylem embolism
drought-resistence
