PJB-2022-295
RESPONSE OF ELEVATED CARBONDIOXIDE AND TEMPERATURE ON SENESCENCE OF HOT CHILLI (Capsicum chinense Jacq.)
SANGITA DAS
Abstract
The aim of the study is to understand the response elevated carbon dioxide and temperature in senescence process of hot chilli Hot chilli (Capsicum chinense Jacq.) plants were subjected to different levels of elevated CO2 and temperature along with control (ambient) condition in the Department of Crop Physiology, AAU, Jorhat, Assam. Hot chilli plants were grown under automated simulated conditions (Carbondioxide Temperature Gradient Tunnels), where temperature and CO2 were regulated by SCADA software. Various water related parameters viz, water potential, osmotic potential, Relative leaf water content and senescence related parameters viz. Lipoxygenase, Malonaldehyde, Relative stress injury were studied. Results indicated that leaf water potential and osmotic potential recorded a significant difference due to elevated CO2 and temperature where maximum increase was noted at 550 ppm CO2 and 2oC higher than ambient temperature (CTGT II). A significantly higher per cent increase in water potential and osmotic potential was recorded in cv. Manipur compared to cv. Assam. Due to elevated CO2 and temperature, a stress induced reduction in RLWC was observed at750 ppm CO2 and 4oC higher than ambient temperature (CTGT III). A significantly lower lipoxygenase activity and H2O2 content was recorded in CTGT II and cv. Assam recorded an increase in H2O2 content compared to cv. Manipur. In CTGT III, a significant increase in H2O2 content was noticed over control. Plants grown under CTGT III, showed reduced membrane stability index causing increase in relative stress injury. A decrease in senescence index was recorded in plants under CTGT II when compared to CTGT III. Various senescence related parameters viz. lipoxygenase, Malonaldehyde content, senescence index was studied and found to have a significant difference at CTGT III compared to control. Similarly, the water related parameters viz, osmotic potential, water potential, relative leaf water potential reported a significant difference amongst the treatments. Moreover, a significant variation has also been observed among the cultivars. Elevated CO2 could reduce the senescence process in hot chilli which might have helped in maintaining the photosynthesis rate during later period of plant development under high temperature. This indicated that the elevated CO2 have the role in altering the physiological processes thereby slowing the senescence process at CTGT II. Various physiological studies viz. measurement of RLWC, Senescence Index, Relative Stress injury, Water potential could help in understanding the role of elevated CO2 and temperature in senescence process of hot chilli.
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