The short-day plant, Pharbitis nil can be induced to flower under continuous light when grown under poor-nutrient, low-temperature or high-light-intensity conditions. Since these conditions act as stress, such flowering can be referred to as stress-induced flowering. The presence of cotyledons is essential for stress-induced flowering. This suggests that the cotyledons exposed to stress produce flower-inducing compound(s) as in photoperiodic flowering. Aminooxyacetic acid (AOA) inhibits the stress-induced flowering.　AOA inhibits the activity of phenylalanine ammonialyase (PAL) which catalyzes the conversion of phenylalanine to t-cinnamic acid resulting in the accumulation of phenylpropanoids, salicylic acid and anthocyanin. Some of these metabolites may be involved in the regulation of stress-induced flowering. Salicylic acid is a most probable candidate among them.