根径向水流导度测定技术的改进

An Improved Technique for Measuring Root Radial Hydraulic Conductivity

根系径向流的水力学性质主要是根的径向水流导度 ,它取决于根径向水流通道的状况。利用改进的现有原位测定根系径向水流导度的蒸腾计技术 ,设计了一个简便的 4室吸水测定装置 ,可一次性获得根木质部水势和根径向水流导度 ,缩短测定时间 10min ,确保测定精度。然后用改进的装置测定了生长在不同水分条件下冬小麦(TriticumaestivumL .)根系的径向水流导度 ,结果显示根系的平均径向水流导度为 4.6 3× 10 -7m·s-1·MPa-1,并随连体植株水分胁迫程度的增大而降低。

The radial hydraulic properties of root could be described as two components: radial hydraulic conductivity and water flow pathways. Measuring the dynamic change of the radial hydraulic conductivity of root in relevance to soil water potential with precise technique is basic to understand hydraulic properties. The tradition potometer attached to the transpiring plant for measuring the hydraulic conductivity has been modified to provide with four chambers which shortens the time and enhance the precision of measurement. The result from using the new technique is consistent with that of previous studies, in which average root radial hydraulic conductivity of winter wheat (Triticum aestivum L.) was 4.63×10 -7 m·s -1 ·MPa -1 and decreased with an increasing water stress of the transpiring plants.