EFFECT OF MODIFIED ENVIRONMENTS ON PLANT GROWTH AND FLOWERING PRODUCTION OF GERBERA

Abstract

Twenty four weeks old seedlings of gerbera, Gerbera jamesoniiL, were maintained under Rambo-plastic nets permitting 85% and 75% natural light intensity from May 15,1991 to October 15, 1991. The significant differences among plants grown under reduced light intensities were observed for leaf number, leaf area, flower number and flower quality as compared to the plants grown under 100% natural light intensity. Plants grown under plastic nets produced double the number of leaves (37) and flowers (10) with better stem length and flower diameter, as compared to plants grown under uninterrupted natural light intensity. The chlorophyll content of leaves was maximum (2,417 mg/g of fresh weight) from the plants grown under net permitting 75% of natural light intensity and was minimum (1.551 mg/g of fresh weight) from plants grown under natural conditions throughout the growing period. It is concluded that increased rate of plant growth and flower production is the result of reduced light intensity only, because air temperature under nets did not differ from the open due to free movement of air through nets. In the second experiment, 72, weeks old seedlings were covered with plastic cover (as complete cover, overhead cover, without cover for control) from November 1990 to February, 1991. The highest number of flowers (32/plant) was produced by the plants maintained under completely covered plastic film but the difference in flower yield and flower quality was only numerically significant.