Measurement of the Respiration-Dependent Component of Intracellular Pressure with an Improved Pressure Probe

概要

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We have improved a previously described pressure probe in the following respects to make it suitable for continuous measurements of intracellular pressure (P^i) in higher plant cells. (1) The oil/cell-sap boundary (meniscus) at the tip of the microcapillary was monitored photo-electrically with a high-resolution image sensor. (2) Adjustment of the plunger and the insertion of the probe into the target cell were performed with specially designed, hydraulic manipulator systems. These improvements allowed us to monitor the meniscus precisely and to maintain the meniscus at a certain position without mechanical perturbation. This system has been successfully used to measure P^i continuously for more than 3 h. With this pressure probe, the dependence on respiration of P^i in the elongation zone of Vigna hypocotyls, which was predicted by Katou and Furumoto (1986a, b), was demonstrated directly. Changes in P^i induced by osmotic stress were also measured quite successfully. The respiration-dependent component of P^i was 30-40 kPa. While this component appears to be very small, the change in P^i under anoxia caused shrinkage of the segment of hypocotyl being examined. Regulation of P^i over a range of several tens of kPa or so should, therefore, make a significant contribution to the control of elongation growth.
日本植物生理学会の論文