Science. 1965 Apr 16;148(3668):339-46. doi: 10.1126/science.148.3668.339.
A method is described which permits measurement of sap pressure in the xylem of vascular plants. As long predicted, sap pressures during transpiration are normally negative, ranging from -4 or -5 atmospheres in a damp forest to -80 atmospheres in the desert. Mangroves and other halophytes maintain at all times a sap pressure of -35 to -60 atmospheres. Mistletoes have greater suction than their hosts, usually by 10 to 20 atmospheres. Diurnal cycles of 10 to 20 atmospheres are common. In tall conifers there is a hydrostatic pressure gradient that closely corresponds to the height and seems surprisingly little influenced by the intensity of transpiration. Sap extruded from the xylem by gas pressure on the leaves is practically pure water. At zero turgor this procedure gives a linear relation between the intracellular concentration and the tension of the xylem.
描述了一种可以测量维管植物木质部中液流压力的方法。正如长期预测的那样，蒸腾过程中的液流压力通常为负值，范围从潮湿森林中的-4 或-5 个大气压到沙漠中的-80 个大气压。红树林和其他盐生植物始终保持在-35 到-60 个大气压的液流压力。槲寄生比其宿主具有更大的吸力，通常高出 10 到 20 个大气压。10 到 20 个大气压的日循环很常见。在高大的针叶树中，存在与高度密切对应的静水压力梯度，而且令人惊讶的是，它受蒸腾强度的影响很小。由叶片上的气体压力从木质部中挤出的汁液几乎是纯水。在零膨压时，该方法给出了细胞内浓度与木质部张力之间的线性关系。
