Osmotic Behavior of Oat Coleoptile Tissue in Relation to Growth.
Osmotic Behavior of Oat Coleoptile Tissue in Relation to Growth.
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DOI：
10.1085/jgp.47.1.83
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发表时间：
1963-09-01
期刊：
影响因子：
--
通讯作者：
Ruesink AW
中科院分区：
文献类型：
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作者：
Ray PM;Ruesink AW
我们努力估计快速生长的燕麦胚芽鞘圆柱体和稀释培养基之间所需的水势差，以支持伸长中涉及的吸水率，（a）通过确定组织既不获得也不失水的甘露醇浓度的传统方法，以及（b）通过测量用不同低渗甘露醇浓度处理组织引起的渗透交换率。两种方法均显示出较大的水势差（3 至 10 个大气压），在某些情况下接近细胞的渗透压。然而，得到的指示是，由甘露醇溶液引起的渗透交换速率，并且可能还有(a)中寻求的平衡响应，是由甘露醇与自由空间的扩散交换速率而不是组织对水的渗透性决定的。在组织的膨胀压因蒸发而降低后，通过将其浸入水中来测量组织的渗透膨胀，该渗透膨胀比涉及甘露醇时至少快两到四倍。通过蒸发-浸没法估算的水渗透率表明，快速伸长的圆柱体的水势在-0.8 至-2.5 个大气压之间，或渗透压的10% 至25% 之间。
Efforts were made to estimate the water potential difference that is required, between rapidly growing oat coleoptile cylinders and dilute medium, to support the rate of water uptake involved in elongation, (a) by the traditional method of determining the concentration of mannitol in which the tissue neither gains nor loses water, and (b) by measuring the rates of osmotic exchanges induced by treating the tissue with different hypotonic mannitol concentrations. Both methods indicated large water potential differences (3 to 10 atm), in some cases approaching the osmotic pressure of the cells. However, indication was obtained that the rates of osmotic exchanges induced by mannitol solutions, and presumably also the equilibrium response sought in (a), are governed by the rate of diffusional exchange of mannitol with the free space rather than by the permeability of the tissue to water. Osmotic swelling of the tissue measured by immersing it in water after its turgor pressure had been reduced by evaporation, was at least two to four times more rapid than when mannitol was involved. The permeability to water estimated by the evaporation-immersion method indicated that rapidly elongating cylinders have water potentials between -0.8 and -2.5 atm, or between 10 and 25 per cent of their osmotic pressure.