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Development of a method for a quick measurement of the root capacity of water uptake and solute transport

开发快速测量根系吸水和溶质运输能力的方法

基本信息

批准号：
13556005
负责人：
HIRASAWA Tadashi
金额：
$ 5.12万
依托单位：
National University Corporation Tokyo University of Agriculture and Technology
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2004
项目状态：
已结题

项目摘要

In order to develop a method for a quick measurement of the root capacity of water uptake and solute transport, we examined whether the root properties of water uptake and solute transport can be estimated by monitoring xylem pressure of a root (referred to the equipment as a root pressure probe) by using the theory of Steudle and Jescke based on the root function as an osmometer or not. The followings are obtained results in the research.(1)Hydraulic conductivity measured under the steady state is considered to be reliable. Hydraulic conductivity measured with the root pressure probe under non-steady state was compared with that measured under the steady state in a maize root. There was a close linear correlation between the hydraulic conductivity obtained from both measurements.(2)NaCl transport was investigated in the excised root of Rhizophora stylosa Griff. The reflection coefficient of the roots was smaller than 0.1 and was smaller remarkably than those previously reported for th … More e herbaceous species. The osmotic potential of the exudated sap from the excised root in the nutrient solutions containing various concentration of NaCl was always equivalent to that of the nutrient solution. These results indicate that NaCl transport accompanied by water is not restricted significantly in the excised root of Rhizophora stylosa Griff.(3)The concentrations of Na^+ and Cl^-became equivalent to that of the nutrient solution in the root about 10 days after the seedlings of Rhizophora stylosa Griff, were transferred to the solution containing NaCl, but the concentration of a shoot remained low. This indicates that Na^+ and Cl^-transport from roots to shoot is restricted significantly. The calculated concentration of Na+ and Cl-in the transpirational stream in roots was also far low compared with the concentration of the nutrient solution. This indicates the transports of Na^+ and Cl^-into roots are also restricted.(4)From the results mentioned above, we conclude that the method, considered in the research, can be employed in evaluating the root capacity of water uptake and, however, it is still required to be investigated whether this method can be adopted for evaluating root properties of solute transport. Less

为了开发一种快速测定根系吸水和溶质运移能力的方法，我们研究了是否可以利用Steudle和Jescke的基于渗透压计的根系功能理论，通过监测根的木质部压力（称为根压探头）来估计根系吸水和溶质运移的特性。研究取得了以下成果。（1）在稳定状态下测量的水力传导率被认为是可靠的。用根压探头在非稳态条件下测定了玉米根系的导水率，并与稳态条件下的导水率进行了比较。从两个测量得到的导水率之间有密切的线性相关性。（2）研究了红海榄离体根中NaCl的运输。根系的反射系数小于0.1，明显小于以往报道的根系反射系数。 ...更多信息 E草本种。离体根分泌液在含不同浓度NaCl的营养液中的渗透势始终与营养液的渗透势相当。这些结果表明，红海榄离体根中NaCl的水分运输没有受到明显的限制。（3）红海榄幼苗转入含NaCl溶液中10 d左右，根中Na^+和Cl^-浓度与营养液相当，但茎中Na^+和Cl^-浓度仍较低。这表明Na^+和Cl^-从根向地上部的运输受到明显的限制。计算的Na+和Cl-的浓度在根的蒸腾流也远低于营养液的浓度相比。这表明Na^+和Cl^-向根中的运输也受到限制。（4）从以上结果可以看出，本研究所采用的方法可以用来评价根系的吸水能力，但能否用于评价根系的溶质运移特性还有待进一步研究。少