Measurement of the relative turgidity of plant leaves under field conditions

A set of instruments working according to the beta-absorption technique was used to carry out continuous field measurements of the relative turgidity of crop plant leaves during a great part of the growing season. The use of a lightproof and waterproof scintillation probe allowed to take measurements even under extreme weather conditions. Results of measurements on sugar beet leaves were plotted as curves together with the daily courses of photosynthetically active radiation and the net photosynthesis rate. They demonstrate the effect of water stress of different intensity and duration on the plant matter formation process. (author)