摘要
利用压力室技术测到的水势是缺乏修正的数值,比实际水势要高出许多,用该方法测定水势,只能反映出水势的大小变化,而不能用其代表木质部内真实的负压。蒸腾使木质部产生的负压最大不会超过-0.1Mpa,木质部内巨大负压的存在缺乏理论依据和直接的实验证据。空穴的必然发生使水柱无法保持连续,故连续水柱不存在。蒸腾状态下木质部水分的移动方式是自上而下分段依次移动的,这一现象与内聚力原理相抵触。蒸腾产生的负压能保持到蒸腾停止后继续使根系吸水。
The water potential measured by using the pressure chamber technique is lack of correctional values, much high- er than the actual one, which can only reflect changes in the size of water potential, rather than represent their true negative pressure inside the xylem. Transpiration can prompt the xylem to produce no more than --0.1MPa limited negative pressure, as a result, the view that there is a huge vacuum inside the xylem is deficient of theoretical basis and direct experimental evidence. Continuous water column doesn＇t exist because the inevitable cavitation make it can not maintain continuous. The water inside xylem is moving from the top to down section by section, deviating from the principle of cohesion. Negative pressure made by transpiration can keep the root absorbing water after transpiration.
出处
《山东林业科技》
2011年第4期89-91,共3页
Journal of Shandong Forestry Science and Technology
关键词
内聚力学说
压力室技术
木质部负压
连续水柱
水分移动方式
Cohesion Theory
Pressure Chamber Technique
Xylem Negative Pressure
Continuous Water Column
Water Move Mode
