Photoperiod and Temperature Influence Flowering Responses and Morphology of Tecoma stans

Abstract

Tecoma stans (L. Juss. Kunth) ‘Mayan Gold’ is a tropical flowering plant that was selected as a potential new greenhouse crop for its physical appearance and drought and heat tolerance. The objective of this study was to quantify how temperature during the finishing stage and photoperiod during propagation and finishing stages influence growth, flowering, and quality. In Expt. 1, plants were propagated from seed under four photoperiods (9, 12, 14, or 16 h) for 35 days. Under long-day (LD) photoperiods (14 h or greater), seedlings were 3.0 to 3.7 cm taller than those propagated under 9-h photoperiods. During the finishing stage, days to first open flower, shoot dry mass, and number of nodes below the terminal inflorescence were reduced when plants were grown under LD photoperiods. In addition, number of open flowers and branches increased under LD photoperiods. Few plants developed visible buds when grown under short-day (SD) photoperiods (12 h or less). In Expt. 2, plants were forced at average daily temperatures of 19, 20, or 22 °C after transplant. Time to first open flower was reduced by 7 days as temperature increased. Inversely, number of visible buds increased by 57 as temperature increased from 19 to 22 °C. Under the experimental conditions tested, the most rapid, complete, and uniform flowering of Tecoma occurred when plants were propagated and finished under LD photoperiods and forced at 22 °C.