Novel Method for Measuring Tissue Pressure in Herbaceous Plants

Tissue pressure is of vital importance for the stability and stiffness as well as metabolic functions of herbaceous plants and has been studied for more than a century. Several measurement methods have been established but require either sophisticated equipment at a fixed workplace or being applicable only to flat structures. We were looking for a mobile system that can be used under greenhouse conditions for long-term measurement of parenchymatous tissue pressure. The mobile sensor system used consists of a micro-optic-mechanical system with a silicon sensor at the tip of a glass fiber and a control unit (Samba 202) for data logging. The sensors were inserted and became ingrown in succulent leaves of Delosperma cooperi, petioles of Caladium bicolor, and flower stalks of Cyclamen persicum. With this method, three distinct phases could be distinguished in the restoration of the parenchymatous tissue pressure after embedding the sensors without drought stress. Under drought stress, three additional phases w...