Spectral Sensitivity of the Promotion and Inhibition of Flowering in Morning Glory (Pharbitis nil)

Abstract

Seedlings of morning glory (Pharbitis nil) were exposed to blue light-emitting diodes (LEDs) with various peak wavelengths, or mixture lights of blue light and red light to confirm the spectral sensitivity to flowering. Flowering responses to the respective LEDs corresponded to the absorption spectrum of cryptochromes, which is one of blue light receptors. On the other hand, the light qualities consisting of rich blue light had an effective influence on flowering responses. The number of flower buds decreased after being exposed to the red-rich light qualities, a situation under which phytochromes absorb well. From our study, we conclude that cryptochromes, which absorb blue light, effectively act on flowering, whereas phytochromes act on the inhibition of flowering in Pharbitis nil under the normal light/dark cycles.