2019 ASHS Annual Conference

Ornamental foliage plants are valued for their exquisite leaves with diverse shapes and colors, yet dark-induced plant senescence or deterioration during transport greatly impacts the quality of foliage plants. Melatonin is an important signaling molecule that affects pleiotropic developmental progresses in plants, and 2-aminoethoxyvinyl glycine (AVG) is a potent inhibitor of ethylene biosynthesis and extensively used for delaying plant senescence and fruit ripening. In this study, we compared the effects of melatonin and AVG in alleviating plant deterioration of three Pilea species (P. cadierei (PC), P. involucrata (PI) and P. mollis (PM)) through foliar sprays of different concentrations of melatonin or AVG prior to dark treatment. Our results showed that PC, PI and PM exhibited distinct responses to melatonin or AVG. PM is the most sensitive species that exhibited significant increases in stem height, leaf area, chlorophyll and anthocyanin content in responses to 50, 100 and 150 µmol·L^-1 of melatonin; similar responses to 150 and 200 µmol·L^-1 of melatonin were observed in PI with regard to these plant characteristics. By contrast, much less effects of AVG on these plant characteristics were observed in PM and PI, although it increased their Fv/Fm values as with melatonin. Unlike PM and PI, PC is generally not responsive to all melatonin and AVG treatments, despite AVG treatments could alter stem elongation. The results may provide growers science-based information for future practical application of melatonin to maintain the quality of ornamental plants during and after transportation.