EFFECTS OF LIGHT QUALITY ON FLOWER AND BUD DEVELOPMENT IN BEGONIA X HIEMALIS-FOTSCH

In two experiments plants to Begonia x hiemalis cv. Schwabenland Red w ere subjected to different light qualities. In the first experiment pl ants were exposed to continuous treatment with white or red light for 4 days at a level of 26 mumol m-2 s-1, and then moved to simulated int erior climatic conditions. In the second experiment the plants were su bjected to the following treatments: 7 days of continuously treatment with darkness or with 4 different light qualities (white blue, green o r red light) at a level of 26 mumol m-2 s-1, followed by 7 days of whi te light treatment with an irradiance level of 45 mumol m-2 s-1. This 2 x 7 days treatment was given 3 times. Red light significantly increa sed the number of flowers and buds by more than 30 % in both experimen ts. Red light also resulted in significantly lower plant height and le ss flower shoot elongation compared to white light. Blue light signifi cantly increased both plant height and flower shoot height.