Salinity and the Hydraulic Conductance of Roots
Salinity and the Hydraulic Conductance of Roots
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盐度和根部的水导率
DOI：
10.1111/j.1399-3054.1976.tb03995.x
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发表时间：
1976
期刊：
影响因子：
--
通讯作者：
G. Ogata
中科院分区：
文献类型：
--
作者：
J. Shalhevet;E. Maas;G. Hoffman;G. Ogata
研究了盐分对番茄（Lycopersicon esculentum Mill.）和向日葵（Helianthus annuus L.）在分根实验中使用盐化营养液测定。实验在两个或三个相对湿度水平和四个溶液渗透势水平下在受控气候室中进行。
根系水通量（Jv）与叶-根介质总水势差（Δ V）呈线性关系，通常有一个小的截距。因此，在这些实验中获得的通量范围内，根导水率（L）不受盐度的影响，番茄L= 0.036 mm h−1 bar−1，向日葵L= 0.0167 mm h−1 bar−1。我们的结果与耦合水和离子吸收的理论分析相一致。
根据Cl−和Na+吸收数据，番茄根系的反射系数（o）计算为0.956，与近零截距一致。向日葵的一个大的截距不能很容易地解释。
相对湿度强烈影响根系生长，在低湿度条件下生长更快。当相对湿度从34%增加到84%时，向日葵植物的蒸腾量减少了20%，而番茄的蒸腾量减少了50%。
The effect of salinity on hydraulic conductance of intact roots of tomato (Lycopersicon esculentum Mill.) and sunflower (Helianthus annuus L.) was determined in split-root experiments using salinized nutrient solutions. Experiments were conducted in controlled climate chambers under two or three relative humidity levels and four solution osmotic potential levels.
The relationship between water flux through roots (Jv) and total water potential difference between the leaves and the root medium (Δψ) was linear, usually with a small intercept. Thus, the root hydraulic conductance (L) was not affected by salinity within the range of fluxes obtained in these experiments, with L= 0.036 mm h−1 bar−1 for tomato and L= 0.0167 mm h−1 bar−1 for sunflower. Our results agreed with theoretical analysis of coupled water and ion uptake.
From Cl− and Na+ uptake data, the reflection coefficient (o) for tomato roots was calculated as 0.956, which was compatible with the near-zero intercept. A large intercept for sunflower could not be readily explained.
Relative humidity strongly affected root growth, with more rapid growth under low humidity conditions. Transpiration of sunflower plants was reduced by 20% when the relative humidity was increased from 34% to 84%, whereas transpiration in tomato was reduced 50%.