Environmental and Physiological Studies on Measurement and Optimization of Root absorption and Translocation in Plants.

本研究的目的是从优化植物-环境系统运输现象的角度，发展新的评价植物完整根的质量吸收和果实的质量积累功能的方法，并分析环境影响这些功能的机理。2002-2004年的主要研究结果总结如下：1.在NFT液体培养系统中，建立了测定完整根部木质部汁液中水分和各种无机离子的吸收速率和离子浓度的新方法，阐明了高温胁迫的短期和长期效应以及短期盐胁迫的影响。2.通过韧皮部对番茄果实物质(汁液和可溶性固形物)通量和韧皮部汁液中可溶性固形物浓度的评估，并结合植物韧皮部运输过程中的渗透调节，分析了盐胁迫和水分胁迫对番茄果实质量积累的影响。3.高压流量仪和压力容器的配合使用使定量分析了不同根系环境下的根系吸收特性。4.提出了一种基于气孔关闭的田间植物冠层蒸腾作用的评价方法。5.应用上述新方法进行了验证，例如，番茄果实快速生长期用浓缩的深层海水进行短期盐胁迫处理，可以诱导韧皮部运输的渗透调节，从而生产出糖、酸、矿物质含量高、风味好的优质番茄。

The aim of this research is to newly develop the methodologies for evaluating functions of mass absorption in intact roots and mass accumulation into fruits and to analyze mechanisms of environmental effects on these functions from the point of view of optimization of transport phenomena in the plant-environment system. The main results obtained from 2002 to 2004 are summarized below :1.In the NFT liquid culture system, the new methodology was established for measurements of uptake rates of water and each inorganic ion and concentrations of the respective ions in.xylem sap in intact roots, and short term and long term effects of the high root temperature stress and effect of the short term salt stress were elucidated.2.Evaluations of fluxes of mass (sap, and soluble solids) into a tomato fruit via phloem and concentrations of soluble solids in the phloem sap were enabled, and effects of salt stress and water stress on mass accumulation into tomato fruits were analyzed with special reference to osmoregulation in phloem transport.3.The cooperative application of the high pressure flow meter and the pressure tank for intact root system of a whole plant enabled quantitative analyses of characteristics of root absorption under various root environments.4.A new method for evaluation of transpiration from plant canopy in a field was developed on the basis of stomatal closure by applying abscisic acid (ABA) to plants.5.By applying the new methodologies developed above, it was verified, for example, that the short-term salt stress treatment with the concentrated deep seawater at the stage of rapid fruit growth of tomato plants can induce the osmoregulation in phloem transport and results in production of high quality tomatoes enriched in sugar, acid, minerals and good flavor.