EFFECTS OF LIGHT DURING SPECIAL PRECOOLING OF TULIP BULBS CV. PAUL RICHTER ON THE CONTENT OF CHLOROPHYLLS IN THE SHOOTS AND ON SUBSEQUENT ANTHESIS

Shoots from bulbs stored under continuous fluorescent illumination (Philips TLD 36 W/84, irradiance 800 mW m^-2) at 5 or 17°C (control) contained chlorophylls a and b. Shoots from bulbs stored in darkness did not contain these pigments.
Anthesis occurred 1.5 days earlier in tulips originating from illuminated special precooled bulbs than in tulips from bulbs kept in darkness.

In another trial, precooled bulbs were subjected to continuous illumination (irradiance 4300 mW m^-2 or 2300 mW m^-2). Anthesis in plants originating from these bulbs was 4 days or 3 days earlier, respectively, than in plants from bulbs kept in darkness.

Since precooling and light stimulate the formation of gibberellins, the content of gibberellins in continuously illuminated bulbs was probably higher than that of bulbs kept in darkness, so leading to earlier anthesis.
Chlorophylls would not have been the cause of earlier anthesis; they simply arose in the presence of light.

IV International Symposium on Flower Bulbs

N. Gorin, H. Zonneveld

https://doi.org/10.17660/ActaHortic.1986.177.108