Effect Of Crop Root Compensation Under The Condition Of Partial And Stressful Supply Of Water And Nitrogen

With the increasingly serious water problems and environmental problems caused byexcessive application of nutrients, how to efficient use of water and fertilizer have beenwidespread concerned. And how to change hairy root line of micro ecosystem structure andfunction, improve the root zone moisture and nutrient availability, compensation effect ofstimulating root growth and absorption, mining plants adapt to potential, research onimproving crop water and nutrient efficiency use were also important. Under the condition ofWater and nitrogen were supplied by four levels:0MPa，‐0.2MPa，‐0.4MPa，‐0.6MPa or4mM、2mM、1mM、0mM (which means sufficient supply, moderate deficiency supply,middledeficiency supply and serious deficiency supply). By using split-root and solution culturetechnique, maize root was used to measure response of corn root growth, absorption ofmoisture and nutrient local supply. The dynamic changes and the affecting factors of rootcompensation resource of the local supply conditions were established, maize rootcompensation effects and its relationship with the treating time were revealed. Theconclusions were as follows:(1) With the increase of water and nitrogen stress, maize root hydraulic conductivitydecreased, compared with the nitrogen stress, the effect of water stress on maize root wasmore outstanding. With the extension of time, both sides of maize root hydraulic conductivitywere increased, the different between the resume normal supply side of the root and the otherside was increased. With the extension of time, unit area and unit root length hydraulicconductivity of recovery1/2root zone of mild stress water supply can close even reached thelevel of control. The hydraulic conductivity, unit area and unit root length hydraulicconductivity of combined root had no significantly changed. Serious deficiency supply hasseriously affected the normal hydraulic conductivity of maize was also found.(2) The growth of maize roots decreased with the increasing intensity of water and nitrogenstress. With the extension of time, the resume normal supply side of the root and the otherside had significant growth, especially the light stress. And with the treatment time increased,the differences between the recovery1/2root zone and the other one were increased. Rootarea, root length and root dry weight of each side of the root had a significantly changed in the early days of the treatment time, and the total root area, total length and total dry weighthad a significantly changed with the different stress intensity.(3) Except essentially unchanged of the control, under the condition of water and nitrogenstress, leaf water potential had a significantly changed and maize leaf water potentialincreased with the treatment time. And the effects of water stress greater than Nitrogen, thecorn leaf water potential had differences between the4treatment after water stress, and thedifferences were larger than that of nitrogen. And changes of leaf water potential of watertreatment were also greater than that of the nitrogen treatment after1/2root were recoverednormal supplied.(4) Under the conditions of4levels in this study, after1/2root were recovered normalsupplied, root hydraulic conductivity, root growth and leaf water potential of maize root had atrend of returned to the control. But under the conditions, only mild stress of root of the above3indicators recovered or closed to normal level in the different treatment time, others werestill take a long time before recovered to the normal level.