Effect of elevated carbon-dioxide levels on morphological and physiological parameters in gladiolus

摘要

Effect of different CO_2 concentrations, i.e., 400 (control), 700 and 900 ppm on morphological and flowering parameters was studied on two gladiolus cvs. American Beauty and Snow Princess under controlled phytotron conditions. Maximum plant height (76.06 cm) was found at 700 ppm CO_2 concentration in cv. Snow Princess but at 900 ppm, the growth declined. Scape width was found maximum in cv. American Beauty in treatment 900 ppm CO_2. Cultivar Snow Princess was found with maximum spike length (57.32 cm) in 700 ppm of CO_2. Rachis length (21.43 cm), leaf length (48.05 cm), number of spikes/plant (1.67) and flowering duration (6.00 day) were found maximum in cv. Snow Princess with 700 ppm CO_2. Number of days taken for spike emergence and leaf dry weight increased with the rise in CO_2 concentration. Maximum number of days for spike emergence (78.73) were recorded in treatment 900 ppm CO_2 concentration in cv. American Beauty. Number of florets/spike and number of leaves/plant were not affected significantly by the rise of CO_2. Leaf area ratio decreased with CO_2 concentration rise which indicates increase in leafiness of plant. With increase in CO_2 concentration nitrogen content decreased. The lowest nitrogen content in leaves was found at 900 ppmCO_2 treatment. Total chlorophyll (a+b) content was found maximum in 700 ppm of CO_2 but got reduced as the concentration was elevated to 900 ppm.