Endogenous factors involved in the regulation of movement and 'memory' in plants

The bioorganic basis of plant movement in two plant systems is described in this article: the circadian rhythmic leaf movement known as nyctinasty and trap movement in the Venus flytrap. The bioactive substances responsible for plant movement, the chemical mechanism of the rhythm, and studies on the key protein controlling nyctinasty are presented. The nyctinastic leaf movement is induced by a pair of leaf-movement factors, and one of each pair is a glucoside. There are two key proteins that are involved in the control of nyctinasty. One is β-glucosidase: a biological clock regulates the activity of β-glucosidase, which deactivates the glucoside-type leaf-movement factor, controlling the balance in the concentrations of the leaf-closing and -opening factors. The other is the specific receptor for each leaf-movement factor: the genuine target cell for each leaf-movement factor is confirmed to be a motor cell from leaflet pulvini, and the specific receptors that regulate the turgor of motor cells are localized in the membrane fraction. The article also discusses the isolation of the “memory” substance from the Venus flytrap and presents a mechanism for this action.