土壤-植被-大气连续体

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文件:Soil Plant Air Continuum.png

Arbitrary numbers picked to represent decreasing water potentials from the soil, through the plant, to the atmosphere. This shows the net movement of water down its potential energy gradient, from highest water potential in the soil to lowest water potential in the air.

The soil-plant-atmosphere continuum (SPAC) is the pathway for water moving from soil through plants to the atmosphere. Continuum in the description highlights the continuous nature of water connection through the pathway. The low water potential of the atmosphere, and relatively higher (i.e. less negative) water potential inside leaves, leads to a diffusion gradient across the stomatal pores of leaves, drawing water out of the leaves as vapour. As water vapour transpires out of the leaf, further water molecules evaporate off the surface of mesophyll cells to replace the lost molecules since water in the air inside leaves is maintained at saturation vapour pressure. Water lost at the surface of cells is replaced by water from the xylem, which due to the cohesion-tension properties of water in the xylem of plants pulls additional water molecules through the xylem from the roots toward the leaf.

thumb|Arbitrary numbers picked to represent decreasing water potentials from the soil, through the plant, to the atmosphere. This shows the net movement of water down its potential energy gradient, from highest water potential in the soil to lowest water potential in the air. The soil-plant-atmosphere continuum (SPAC) is the pathway for water moving from soil through plants to the atmosphere. Continuum in the description highlights the continuous nature of water connection through the pathway. The low water potential of the atmosphere, and relatively higher (i.e. less negative) water potential inside leaves, leads to a diffusion gradient across the stomatal pores of leaves, drawing water out of the leaves as vapour. As water vapour transpires out of the leaf, further water molecules evaporate off the surface of mesophyll cells to replace the lost molecules since water in the air inside leaves is maintained at saturation vapour pressure. Water lost at the surface of cells is replaced by water from the xylem, which due to the cohesion-tension properties of water in the xylem of plants pulls additional water molecules through the xylem from the roots toward the leaf.

拇指 | 任意选择的数字代表从土壤，通过植物，到大气的水分潜力的减少。这表明水的净运动顺势能梯度下降，从土壤中的最高水势到空气中的最低水势。土壤-植物-大气连续体(SPAC)是水分从土壤通过植物进入大气的途径。描述中的连续体强调了通过这条通道连接水的连续性。大气的低水势，以及相对较高的水势。叶片内部的水势，导致气孔的扩散梯度，将水以水蒸气的形式从叶片中抽出。随着水蒸气从叶片中蒸发出来，叶肉细胞表面的水分子进一步蒸发，以取代损失的分子，因为叶片内部空气中的水分保持在饱和蒸气压下。细胞表面失去的水分被木质部的水分所代替，由于植物木质部水分的内聚力-张力特性，通过木质部从根部向叶部吸收额外的水分子。

Components

The transport of water along this pathway occurs in components, variously defined among scientific disciplines:

• Soil physics characterizes water in soil in terms of tension,
• Physiology of plants and animals characterizes water in organisms in terms of diffusion pressure deficit, and
• Meteorology uses vapour pressure or relative humidity to characterize atmospheric water.

The transport of water along this pathway occurs in components, variously defined among scientific disciplines:

• Soil physics characterizes water in soil in terms of tension,
• Physiology of plants and animals characterizes water in organisms in terms of diffusion pressure deficit, and
• Meteorology uses vapour pressure or relative humidity to characterize atmospheric water.

土壤物理学用张力来描述土壤中的水; 植物和动物的生理学用扩散压力不足来描述生物体中的水; 气象学用蒸汽压力或相对湿度来描述大气中的水。

SPAC integrates these components and is defined as a:

...concept recognising that the field with all its components (soil, plant, animals and the ambient atmosphere taken together) constitutes a physically integrated, dynamic system in which the various flow processes involving energy and matter occur simultaneously and independently like links in the chain.

SPAC integrates these components and is defined as a:

...concept recognising that the field with all its components (soil, plant, animals and the ambient atmosphere taken together) constitutes a physically integrated, dynamic system in which the various flow processes involving energy and matter occur simultaneously and independently like links in the chain. John R. Philip (1966). Plant water relations: some physical aspects. Annu. Rev. Plant Physiol. 17, 245–268.

SPAC 集成了这些组成部分，并被定义为: ... 概念认识到田地及其所有组成部分(土壤、植物、动物和周围大气)构成了一个物理综合的、动态的系统，其中涉及能量和物质的各种流动过程同时发生，独立地像链条中的环节一样。约翰 · 菲利普(1966)。植物水分关系: 一些物理方面。女名女子名。牧师。植物生理学。17, 245–268.

This characterises the state of water in different components of the SPAC as expressions of the energy level or water potential of each. Modelling of water transport between components relies on SPAC, as do studies of water potential gradients between segments.

This characterises the state of water in different components of the SPAC as expressions of the energy level or water potential of each. Modelling of water transport between components relies on SPAC, as do studies of water potential gradients between segments.

这表示 SPAC 不同组成部分的水状态，即每个组成部分的能量水平或水势的表达式。水分在各组成部分之间传输的模型依赖于 SPAC，同样依赖于水分段之间水势梯度的研究。

See also

• Ecohydrology
• Evapotranspiration
• Hydraulic redistribution; a parameter now being considered in the soil-plant-atmosphere modeling community
• Transpiration stream

• Ecohydrology
• Evapotranspiration
• Hydraulic redistribution; a parameter now being considered in the soil-plant-atmosphere modeling community
• Transpiration stream

=

• 生态水文学
• 水力重新分配参数正在土壤-植物-大气模拟群落
• 蒸腾流中被考虑。

References

Category:Climatology Category:Ecological processes Category:Hydrology Category:Soil physics Category:Water and the environment Category:Plant physiology

类别: 气候学类别: 生态过程类别: 水文学类别: 土壤物理类别: 水与环境类别: 植物生理学

This page was moved from wikipedia:en:Soil-plant-atmosphere continuum. Its edit history can be viewed at 土壤-植被-大气连续体/edithistory