Exposure of young pepper plants to chilling temperatures delays the development of terminal flower buds to flowering during post-stress growth. Degree of adverse influence depends on chilling intensity, exposure duration and varietal sensitivity. `Ma Belle' pepper plants were grown in a greenhouse (GH) during winter months on the St. Paul campus, No supplemental lighting was provided. When plants were at the 2- to 3-leaf stage, they were foliar sprayed with mefluidide (Technical grade) at 0, 5, 10 and 15 ppm. One day after treatment, some plants were transferred from GH to a cold room (3° ∼4°C day/night) with 12-h photoperiod. Treatad plants remaining in the GH served as the control. Plants were chilled for 1, 2, 4 and 6 days and then brought back to the GH for post-stress growth and development observation. Treated and untreated plants grown in the GH showed no difference in days to flowering, and reached 50% flowering at about 62 days after treatment. When untreated plants were chilled for 1,2,4 and 6 days, they showed a delay of 8, 18, 30 and 34 days, respectively, to flowering, If not killed, as compared to the control The long delay to flowering was due to the injury of the terminal flower buds. After 4 and 6 days of chilling, most terminal flower buds were killed. However, when plants were treated with mefluidide and subsequently chilled days to flowering were significantly shortened. A difference of 10-12 days was observed between chilled untreated plants and chilled treated plants. Concentrations of 5 to 15 ppm were equally effective in protection against chilling.
Regulation of Flowering Timing by ABA-NnSnRK1 Signaling Pathway in Lotus
