Effects Of Fertilization On Root Hydraulic Lift And Physiological Characteristic In Astragalus Adsurgens

The relationship between plant and water under drought condition is the main research field of plant physiologist and plant ecologist. More and more researches are focused on plant root hydraulic lift; however, few researches about the effects of fertilization on root hydraulic lift were reported by now. In this research, the effects of fertilization on root hydraulic lift, physiological characteristics and soil nutrition activity of Astragalus adsurgens in upper basin was investigated through root dividing method by supplying different quantity of fertilization to down parts of roots. The main results were as follows:1. The water volume of hydraulic lift increased with the increase of fertilizer supplying. Poa pratensis L. planted in upper basin without irrigation grew better than control.2. The growth and physiology activity of roots in Astragalus adsurgens were promoted by fertilization. The fresh weight, dry weight and volume of roots of Astragalus adsurgens were enhanced with more fertilizer compared with control treatment, which increased ability of roots to absorb deep soil water and to release water to upper dry soil. Also, fertilization enhanced water potential in Astragalus adsurgens' roots and leaves.3. Fertilization increased the efficiency of Astragalus adsurgens hydraulic lift, so the photosynthesis, transpiration and stomatal conductance of Astragalus adsurgens were improved, which could synthesize and accumulate more substances to adapt stress.4. Proline and soluble sugar, as osmotic adjustment substances, were increased with the increase of fertilizer supply under drought condition.5. The hydraulic lift of Astragalus adsurgens could activate soil nutrition in upper basin and fertilization accelerated the degree of activity. The active phosphorus in upper basin soil in the low fertilizer and more fertilizer increased by 13.9% and 33.2%, respectively, compared with than control treatment group, and the active potassium increased by 20.4% and 22.8%, respectively. Furthermore, soil respiration rate in upper basin in the low fertilizer and more fertilizer increased by 14.9% and 51.4%, respectively, and the organic matter content decreased by 17.8% and 19.6%, respectively.