干旱区生态环境知识资源中心

Under hydroponic culture conditions, we studied the relationship between two different types of root hydraulic conductivity of maize (Zea mays L.) and its leaf water status. The results have proved the inaccuracy of the single root hydraulic conductivity (Lp(sr)) to describe the ability of water uptake by maize roots, which can be better described by the whole root systems hydraulic conductivity (Lp(wr)). Moreover, Lp(wr) can be measured easier. Although the whole roots surface area (WRA), which integrated all the root characters, such as root dry weight, volume and length, represent the interaction between root and soil (or water in soil solutions) better, there is no significant relationship between WRA and Lp(wr), and leaf water potential because part of the roots has no activity for water uptake. However, active root surface area (ARA) truly reflects the level of root metabolic activity and root function efficiency, i.e., the ratio of the active roots to the whole roots. Hence, ARA has a significant linear correlation with Lp(wr). Because of the high plasticity of plant root systems architecture and metabolism under changed water and nutrition conditions, the relationship between single root Lp(sr) and whole root Lp(wr) and between WRA and ARA are not positively linear correlated. Results demonstrate that the whole root Lp(wr) described by ARA can reflect more accurately both the water uptake by plant roots and the leaf water status than the single root Lp(sr).