SUPATRA SEN AND S. MUKHERJI
Abstract
Seasonal environmental patterns of temperature, day length, humidity etc. provide organisms with a calendar to which developmental changes are "physiologically locked." The respiratory activity of a plant depends upon its constitutional type and genotypic characteristics; it differs from organ to organ and with the availability of substrate, the phase of development, the state of activity and also the environmental conditions. In this paper, rate of respiration along with the activities of three important respiratory enzymes viz. Fructose 1,6-bisphosphate aldolase, Succinate dehydrogenase and Glucose-6 phosphate dehydrogenase were measured in three different seasons of the year -winter, summer and rainy in two developmental stages - pre flowering (35 D) and post flowering (75 D) in Tomato (Lycopersicon esculentum Mill. var. Pusa Ruby). The three enzymes belong to three different respiratory pathways - Glycolysis, TCA cycle and Pentose Phosphate pathway. The activities of all the three respiratory enzymes assayed along with the respiratory rate exhibited identical trends in recording maximum activity in the winter season. Their values sharply decreased in the summer and recorded a rainy minima. All the three enzymes and rate of respiration recorded higher values in the pre flowering stage (35 D) as compared to the post flowering (75 D) in all three seasons. Winter proved to be the most physiologically active for Lycopersicon with a high demand for energy with diminishing trends in summer followed by rainy.