How does water get through roots
How does water get through roots
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DOI：
10.1093/jxb/49.322.775
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发表时间：
1998-05
影响因子：
6.9
通讯作者：
E. Steudle;C. Peterson
中科院分区：
文献类型：
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作者：
E. Steudle;C. Peterson
对水的吸收。相反，在低蒸腾速率下，如夜间或胁迫期间，根据最近对幼年初生代(干旱、高盐、营养缺乏)、玉米根系的研究结果，提出了质外体路径移动的模型，该模型将较少地利用质外体路径，并使水力水穿过根部。这表明，复杂的‘COM阻力将是很高的。根的水通道和解剖结构的作用导致了水和溶质在跨细胞路径上的复合运输。水流量的平行调节或在质外体、共生体和跨细胞吸收的调节中，在缺乏Suban的较老的植物根部，在水分通过质外体组分的过程中发挥着重要的作用。这种复合材料可以穿过不同的组织。这些被串联排列的端口模型解释了植物是如何被设计成在根柱内(表皮、外胚层、中心层)根据皮层、内胚层、中柱薄壁组织和茎的需求来优化水分吸收，以及外部因素如何影响水分管状元素)。这些跨越根部的结构通道的贡献。对根部的整体径向水力阻力进行了分析。结果表明，早期代谢关键词：复合运输模型、内皮层、外壁维管成熟、轴(纵)向水力真皮、导水率、反射系数、根、木质部内阻力通常不受速率限制。水，水的渠道。根据该模型，在平行的径向路径之间存在快速的水交换，因为与营养离子等溶质相反，每次引入水很容易接触细胞膜。质外体的作用是为地上部分的障碍物(Casparian带和Suberin片层)提供土壤水分，这是根的基本功能之一。讨论了水根内、外胚层的发育过程。模型
uptake of water. On the contrary, at low rates of transpiration such as during the night or during stress conOn the basis of recent results with young primary ditions (drought, high salinity, nutrient deprivation), maize roots, a model is proposed for the movement of the apoplastic path will be less used and the hydraulic water across roots. It is shown how the complex, ‘com- resistance will be high. The role of water channels posite anatomical structure’ of roots results in a ‘com- (aquaporins) in the transcellular path is in the fine posite transport’ of both water and solutes. Parallel adjustment of water flow or in the regulation of uptake apoplastic, symplastic and transcellular pathways play in older, suberized parts of plant roots lacking a suban important role during the passage of water across stantial apoplastic component. The composite transthe different tissues. These are arranged in series port model explains how plants are designed to within the root cylinder (epidermis, exodermis, central optimize water uptake according to demands from the cortex, endodermis, pericycle stelar parenchyma, and shoot and how external factors may influence water tracheary elements). The contribution of these struc- passage across roots. tures to the root’s overall radial hydraulic resistance is examined. It is shown that as soon as early metaxy- Key words: Composite transport model, endodermis, exolem vessels mature, the axial (longitudinal) hydraulic dermis, hydraulic conductivity, reflection coefficient, root, resistance within the xylem is usually not rate-limiting. water, water channels. According to the model, there is a rapid exchange of water between parallel radial pathways because, in contrast to solutes such as nutrient ions, water per- Introduction meates cell membranes readily. The roles of apoplastic One of the essential functions of roots is to supply the barriers (Casparian bands and suberin lamellae) in the shoot with water from the soil. The process of water root’s endo- and exodermis are discussed. The model