A root is a root is a root? Water uptake rates of Citrus root orders
A root is a root is a root? Water uptake rates of Citrus root orders
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DOI：
10.1111/j.1365-3040.2010.02223.x
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发表时间：
2011-01-01
影响因子：
7.3
通讯作者：
Rachmilevitch, Shimon
中科院分区：
文献类型：
--
作者：
Rewald, Boris;Ephrath, Jhonathan E.;Rachmilevitch, Shimon
关于根序的生理功能的知识很少。在这项研究中，一个系统，以监测根订单之间的水通量的小型化室开发。对4年生福氏柑不同根序的根系形态和水分通量进行了分析。8个根序的直径表现出广泛的重叠，但组织密度和比根面积（SRA）的差异是明确区分的。第一级根占根分支生物量的30%，表面积的50%，第五级根占表面积的5%（20%生物量）。根序被确定为水通量的决定因素。一级根表现出显着较高的吸水率比第二和第三根订单，而第四和第五根订单表现出水分过剩。水分过剩表明发生水力再分配（HR）作为渗透势的差异的结果。我们建议，植物可以利用水力再分配，以防止粗根干燥和/或增加养分的获取。我们的研究表明，新的“微型消耗室”的方法，使每个根序的水通量的直接测量，可以是一个主要的工具，为未来的研究根序性状。
Knowledge about the physiological function of root orders is scant. In this study, a system to monitor the water flux among root orders was developed using miniaturized chambers. Different root orders of 4-year-old Citrus volkameriana trees were analysed with respect to root morphology and water flux. The eight root orders showed a broad overlap in diameter, but differences in tissue densities and specific root area (SRA) were clearly distinguishable. Thirty per cent of the root branch biomass but 50% of the surface area (SA) was possessed by the first root order, while the fifth accounted for 5% of the SA (20% biomass). The root order was identified as a determinant of water flux. First-order roots showed a significantly higher rate of water uptake than the second and third root orders, whereas the fourth and fifth root orders showed water excess. The water excess suggested the occurrence of hydraulic redistribution (HR) as a result of differences in osmotic potentials. We suggest that plants may utilize hydraulic redistribution to prevent coarse root desiccation and/or to increase nutrient acquisition. Our study showed that the novel 'miniature depletion chamber' method enabled direct measurement of water fluxes per root order and can be a major tool for future studies on root order traits.