Observation of Stomatal Movements of Intact Plants Using an Image Instrumentation System with a Light Microscope

Abstract

In order to observe the stomatal response of intact plants to environmental changes under growing conditions, we developed a remote-control image instrumentation system with a light microscope. This system is composed of: (1) a light microscope with a wide working distance (13 mm) at high magnification (ca. 1,600-fold magnification on a TV monitor); (2) a movable microscope stage designed to permit the passage of conditioned air along both sides of a fixed leaf and for illuminating from above and below; (3) a high-sensitivity SIT camera (S20 type spectral response) and a monochromatic TV monitor with high resolution and small distortion, used to observe the microscope image in a separate room (stomata can be observed with single reflected or transmitted light above ca. 0.1 mW/cm²); (4) remote controllers to adjust camera sensitivity, microscope focus and movement of the visual field of the microscope image from the separated observation room. This system solved the problems encountered with an ordinary light microscope in observing stomatal movement of intact growing plants. This system also can be used to observe many intact stomata because of its easy and rapid operation. Furthermore, the stomatal aperture and the ratio of transpiration from the cuticle to that from the stomata can be accurately determined using this system.