Non-destructive estimation of root pressure using sap flow, stem diameter measurements and mechanistic modelling
Non-destructive estimation of root pressure using sap flow, stem diameter measurements and mechanistic modelling
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DOI：
10.1093/aob/mcs249
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发表时间：
2013-02-01
期刊：
影响因子：
4.2
通讯作者：
Steppe, Kathy
中科院分区：
文献类型：
--
作者：
De Swaef, Tom;Hanssens, Jochen;Steppe, Kathy
水分在植物中通过木质部向上运动通常归因于黏结张力理论，作为对蒸腾的响应。在一定的环境条件下，根压也有助于木质部向上的水流。虽然根压的发生已被广泛认识，但对根压发生的确切机制、主要影响因素以及根压产生的后果尚不清楚。在园艺作物中，如番茄（茄），根压被认为会导致细胞破裂，并对市场产量产生重要影响。尽管根压研究面临挑战，但这一领域的进展有限，可能是因为直接测量根压存在困难，这促使人们需要间接和非破坏性的测量技术。提出了一种新的方法，允许非破坏性和非侵入性的根压力估计，利用连续测量番茄液流和茎直径的变化，结合机械流动和储存模型，基于内聚张力原理。蒸腾驱动的液流速率通常与茎粗变化呈负相关；然而，在低蒸腾条件下，这种反比关系不再有效。液流速率和茎径变化之间的解耦在数学上与根压有关。根压可以用一种非破坏性的、可重复的方式来估计，只使用外部植物传感器和机械模型。
Upward water movement in plants via the xylem is generally attributed to the cohesiontension theory, as a response to transpiration. Under certain environmental conditions, root pressure can also contribute to upward xylem water flow. Although the occurrence of root pressure is widely recognized, ambiguity exists about the exact mechanism behind root pressure, the main influencing factors and the consequences of root pressure. In horticultural crops, such as tomato (Solanum lycopersicum), root pressure is thought to cause cells to burst, and to have an important impact on the marketable yield. Despite the challenges of root pressure research, progress in this area is limited, probably because of difficulties with direct measurement of root pressure, prompting the need for indirect and non-destructive measurement techniques.A new approach to allow non-destructive and non-invasive estimation of root pressure is presented, using continuous measurements of sap flow and stem diameter variation in tomato combined with a mechanistic flow and storage model, based on cohesiontension principles.Transpiration-driven sap flow rates are typically inversely related to stem diameter changes; however, this inverse relationship was no longer valid under conditions of low transpiration. This decoupling between sap flow rates and stem diameter variations was mathematically related to root pressure.Root pressure can be estimated in a non-destructive, repeatable manner, using only external plant sensors and a mechanistic model.