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Water acquisition in rainfed lowland rice evaluated through the isotope analysis of xylem water

通过木质部水的同位素分析评估雨养低地水稻的水获取

基本信息

批准号：
13575019
负责人：
KONO Yasuhiro
金额：
$ 8.45万
依托单位：
Chubu University
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

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-13575019/
关键词：
international researchers collaboration Zambia ; Philippines ; Bangladesh hydrogen stable isotope water cycles aerenchyma xylem sap phytosplinker hydraulic lift 降水地下水同位体効果深根ザンビアバングラデシュ根系天水田 δD

项目摘要

The aim of the research was to establish a methodology to identify crop species or varieties that acquire water from deeper soil layers. We have focused on the natural abundance of hydrogen isotope ratio (dD) in water of both soil and xylem sap. In the field investigation at Zambia, we have analyzed dD in precipitation and the groundwater, and found that while the groundwater had a constant dD values through the experimental period the precipitation showed a heavy fluctuation in dD values. Further analysis of the xylem sap of crops grown in the field has shown also the fluctuated dD values, suggesting the effect of the precipitation. However, there were significant differences in the dD fluctuation between species; a particular species had dD values always closer to the groundwater comparing with other species. The results imply the species differences in the dependency on the groundwater as water source. To explain the specific differences, the anatomical investigations of the roots were conducted. As a result, it was found that the species with high dependency on the groundwater did not develop aerenchyma at all but the species with low dependency developed well. Moreover, it was found that a crop species occurs hydraulic lift that is a water movement through a plant root system. This was the first report of hydraulic lift in agricultural field study. We have further examined if hydraulic lift can increase with certain agricultural practices, and found that shading is an effective means. It is assumed that plants with deeper root system may be utilized as a sprinkler-like function by regulating hydraulic lift.

该研究的目的是建立一种方法来识别从更深的土壤层获取水分的作物种类或品种。我们重点关注土壤和木质部汁液中氢同位素比 (dD) 的自然丰度。在赞比亚的实地调查中，我们对降水和地下水的dD进行了分析，发现在整个实验期间，地下水的dD值保持恒定，而降水的dD值却出现了剧烈的波动。对田间作物木质部汁液的进一步分析也显示了 dD 值的波动，表明降水的影响。然而，物种之间的 dD 波动存在显着差异；与其他物种相比，特定物种的 dD 值始终更接近地下水。结果表明物种对地下水作为水源的依赖程度存在差异。为了解释具体的差异，对根进行了解剖学研究。结果发现，对地下水依赖性高的物种根本不发育通气组织，而对地下水依赖性低的物种则发育良好。此外，还发现作物物种会发生水力升力，这是水通过植物根系的运动。这是液压升降机在农业领域研究的第一份报告。我们进一步研究了液压升力是否可以通过某些农业实践来增加，并发现遮阳是一种有效的手段。假设具有较深根系的植物可以通过调节液压升力来用作类似喷水器的功能。