Effect of LEDs on flower bud induction in Chrysanthemum morifolium cv. Zembla

The effect of LEDs was studied to induce flower under artificial long days (LD) in Chrysanthemum morifolium cv. Zembla plants, using light emitting diodes (LED) @ PAR m-2 s-1 80% Red / 20% Blue maintained @ 100 µ mol m- 2 s- 1 using royal blue light @ 455 nm and red light @ 640 nm wavelengths and compared with short day (SD) length. Difference in growth and flowering response were also investigated. Stem length is determined as a function of internode length which could be the function of attaining minimum number of leaves required for expressing the diurnal response using LEDs. Chrysanthemum plants exhibited a strong diurnal response attained in leaves and transmitted to the apex and took minimum (28 days) and maximum time (61 days) with an exposure to LEDs with (15h) and without (11h) additional blue spectrum, respectively. However, bud induction was possible earliest due to low red/far ratio in the extended exposure of plants with blue LEDs.