干旱胁迫下磷营养对不同作物苗期根系导水率的影响

Effects of Phosphorus on Root Hydraulic Conductivity of Crops under Drought Stress

通过控制灌水量 (正常供水、中度及重度干旱胁迫 )的盆栽试验 ,采用压力室法测定了玉米、小麦和大麦苗期的根系导水率变化 ,研究在磷素控制下 ,旱后复水过程中根系导水率恢复能力。结果表明 ,不同水分状况下 ,根系的导水率无磷处理明显小于有磷处理 ,且随干旱程度的加重下降加剧 ;复水过程中 ,前者的恢复能力显著弱于后者 ,表明磷营养对增强作物对干旱胁迫的适应性及提高恢复能力具有非常重要的作用。干旱和磷胁迫对不同作物及不同品种苗期根系导水率的影响有所区别 ,小麦和大麦在正常供水情况下的导水率相对较高 ,而且有磷与无磷处理间的差异非常显著。抗旱品种陕合 6号具有较高的导水率和复水后较强的恢复能力 ;而水分敏感型品种郑引 1号 ,干旱导致根系导水率下降显著 ,复水后恢复能力也较弱。

Under different phosphorus levels(+P and -P), the pot experiments were carried out to study the variation of root hydraulic conductivity (Lp r) of corn, wheat and barley seedlings treated with different irrigation (normal water supply, medium drought stress, heavy drought stress), and the recovery ability of Lp r during the course of water re-supplies in the pressure chamber. The results showed that under different water regime, the Lp r of -P was always lower than that of +P treatment, and the former decreased more sharply than the latter with the strengthening of drought. The Lp r recovery ability of the former was obliviously lower than the latter during the course of water re-supplies, and it indicated that phosphorus took a very important role on improving the adaptability to drought and Lp r recovery ability of crops. The influence of drought stress and phosphorus stress to Lp r of different crops and cultivars was different. Wheat and barley had higher Lp r under normal water supply, and the differentiation was great between the treatments of +P and -P. To the drought-resistant cultivar Shanhe 6, pre-stressed seedlings had higher Lp r and stronger Lp r recovery ability after water re-supplies; but to water-sensitive cultivar Zhengyin 1, the Lp r decreased largely under drought stress, and Lp r recovery ability was weak after water re-supplies.