Flowering Regulation of Potted Bougainvillea Plants under Five Water Treatments [RESEARCH NOTE]

Bougainvillea (Bougainvillea buttiana) is a very popular evergreen landscape plant in the tropical and subtropical areas. The objective of this study was to investigate the growth, flowering, and physiological performance of bougainvillea ‘Taipei Red’ cultivar in response to water-stress conditions that can potentially be used to maximize the economic efficiency and benefits in the development and ACC potential of bougainvillea plants grown in controlled environments. Potted plants were subjected to five different levels of soil VWC: 60% (control), 40%, 20%, 1/3 of leaves visually observed to be drooping (equivalent to 18% VWC), and 2/3 of leaves drooping (15% VWC). These five irrigation treatments were applied to those commercial potted plants without flowers from the beginning until the first flower buds appeared, after which normal irrigation was resumed until the end of this experiment. As VWC% decreased, shoot growth rate and days to visible first flower buds decreased. Whereas, leaf abscission, numbers of flower buds and shoots per plant, and ACC content in leaves increased. The 15% VWC irrigation treatment induced the first flower buds to become visible in fewer days and produced more flower buds and shoots and higher ACC content, but shoot growth rate and leaf abscission declined. Whereas, there were no significant differences in bract size and longevity under all %VWC water deficit irrigation treatments and control. Thus, the widely grown flowering potted bougainvillea, ‘Taipei Red’ adapts well to an irrigation schedule of 15% VWC, which can be considered an effective tool for regulating cultivation practices.