Abstract
Effects of a simulated microgravity (SMG) by horizontal clinorotation and other physiological factors on shoot growth of lettuce seedlings were examined under light condition. The growth of the lettuce shoot (mainly consisting of leaf organ) was significantly stimulated by SMG than that under control condition at 1g. This suggested that SMG might stimulate leaf expansion in a manner specific to light-irradiation. We further examined whether or not the SMG-stimulated leaf responses are related to the other factors such as the angle of incidental light, humidity, nutritional status, and also water and/or mineral-stress-related enzymes and molecules. We found that the SMG responses of lettuce leaf may involve both the water transport and redox control of the organ at least in a part.
