Influence of Photoperiod, Temperature, and Node Position on Vegetative Shoot Growth of Greenhouse Azaleas, Rhododendron cv.1

Abstract

An increase in shoot length and shoot dry weight and a decrease in number of shoots per lateral branch, with no effect on number of leaves per shoot, was observed on sheared azaleas grown under increased daylengths in environmental chambers or greenhouses. Plants grown at low (24-19°C) temperatures in environmental chambers had greater shoot lengths, higher numbers of shoots, more leaves per shoot, and decreased shoot dry weight. Decreases in shoot length, number of shoots, number of leaves per shoot, and shoot dry weight occurred as node position for shearing increased (counting from the shearing point). Thus, an inverse relationship apparently exists between node position for shearing and shoot growth in greenhouse azaleas.