Hydraulic Conductivity and Volumetric Elastic Modulus in Giant Algal Cells: Pressure- and Volume-Dependence
Hydraulic Conductivity and Volumetric Elastic Modulus in Giant Algal Cells: Pressure- and Volume-Dependence
复制标题
巨藻细胞中的水力电导率和体积弹性模量：压力和体积依赖性
DOI：
10.1007/978-3-642-65986-7_8
复制
发表时间：
1974
期刊：
影响因子：
--
通讯作者：
E. Steudle
中科院分区：
文献类型：
--
作者：
U. Zimmermann;E. Steudle
应用非平衡态热力学的唯象方程，可以对藻类细胞和高等植物中的水输运进行充分的处理，因为该理论考虑了水流和溶质流之间的耦合（KATCHALSKI和CURRAN，1965）。对随时间变化的水分传输的分析表明，细胞与其周围介质之间的水分交换速率常数由细胞的几何参数、水力传导率Lp和细胞壁的体积弹性模量e决定（参见图1）。DAINTY，1963）。除了少数例外，Lp和ε还不能直接测量，尽管了解它们的值对于研究植物的水分调节（STEUDLE和ZIMMERMANN，1974 a）、高等植物的水分关系和细胞生长是非常重要的。我们缺乏这样的数据，部分原因是直接测量驱动力的困难，特别是细胞内的静水压力。如前所述（ZIMMERMANN等人，1969年），我们开发了一种压力探针，用于直接测量巨型藻类细胞内的压力。这种方法也适用于高等植物。使用压力探针，可以从细胞体积变化和由渗透压和静水压力梯度引起的水流来确定Lp和e。还可以测量Lp和e对驱动力的依赖性。本文报道了在柔曲丽藻（NitellaflexilisandValoniutricularis）和离体丽藻细胞壁上的这种测量结果。用年轻和年老的细胞进行测量，以研究由于生长引起的Lp和ε的变化。
An adequate treatment of water transport ¡n algal cells and higher plants can be achieved by applying the phenomenological equations of non-equilibrium thermodynamics, since this theory allows for the coupling between water flow and solute flows (KATCHALSKI and CURRAN, 1965). Analysis of time-dependent water transport shows that the rate constant of water exchange between the cell and its surrounding medium is determined by the geometric parameters of the cell, by the hydraulic conductivity, Lp, and the volumetric elastic modulus e of the cell wall (cf. DAINTY, 1963). With a few exceptions Lpand ε have not yet been accessible to direct measurement, although knowledge of their values would be of great importance in studying osmoregulation (STEUDLE and ZIMMERMANN, 1974a), water relations of higher plants and cell growth. We lack such data partly because of the difficulties in measuring the driving forces directly, particularly the hydrostatic pressure inside the cell. As described previously (ZIMMERMANN et al., 1969), we have developed a pressure probe for directly measuring the pressure inside giant algal cells. This method can also be applied to higher plants. Using the pressure probe, Lpand e can be determined from the cell volume changes and the water flows induced both by osmotic and hydrostatic pressure gradients. The dependence of Lpand e on the driving forces can also be measured. Such measurements are reported in this paper onNitella flexilisandValonia utricularis, and on isolatedNitellacell walls. The measurements were performed with younger and older cells to investigate changes of Lpand ε due to growth.