Inhibition of Transpiration in Rice by Prohydrojasmon Compared with That by Commercially Available Microcrystalline and Paraffin Wax Agents

Prohydrojasmon (PDJ), a synthetic derivative of the plant hormone jasmonic acid, has been identified as a plant growth regulator used in various fruit and rice seedlings. In this study, we demonstrate the inhibition of transpiration by PDJ in the indica rice cultivar cv. Takanari compared with commercially available microcrystalline and paraffin wax agents in a greenhouse. Microcrystalline and paraffin wax agents inhibited approximately 30%–50% transpiration 3 h after application, and the inhibition lasted for seven days after treatment, depending on the concentration and the agent used. In contrast, PDJ inhibited approximately 40%–80% transpiration compared with control 0.5 h after treatment, and the effect lasted for one day. However, the effect almost disappeared 7 days after treatment. Thus, PDJ affects transpiration differently than commercially available products and could be used to lower excess transpiration in rice, specifically when an early, transient, and reversible inhibition is needed.