PHYSIOLOGICAL CHANGES AND GROWTH PARAMETERS OF PHASEOLUS VULGARIS L. CALLI CULTURES BY CHITOSAN AND CALCIUM PANTOTHENATE UNDER HEAT STRESS

The current study was carried out with the aim of determining the improvement in physiological parameters as a result of treatment with Chitosan (Chit.) and Calcium Pantothenate (CP) compounds and its impact on the growth parameters of Calli cultures of Phaseolus vulgaris L. growing in Murashige and Skoog (MS) media under normal conditions and heat stress conditions. Compounds were used at different concentrations of 0, 50, and 100 μM of Chit. and 0, 2.0, and 4.0 mg L-1 of CP. The increase in temperature at 35°C reduced all physiological indicators and had a negative impact on growth indicators. Treatment with Chit and CP contributed to the improvement of physiological study indicators, and its positive effect was reflected in growth indicators, as calli culture growing under natural conditions and treated with concentrations of 100 μM of Chit provided and 4.0 mg L-1 of CP. The highest mean content of chlorophyll a and total chlorophyll reached 1.471 and 2.261 mg g-1 FW, respectively. The cultures growing under natural conditions were recorded in the media consisting of 0 μM of Chit. and 4.0 mg L-1 of CP, the highest mean of chlorophyll b reached 0.750 mg g-1 FW. In contrast, the concentration of 50 μM of Chit was recorded. and 4.0 mg L-1 of CP had the highest mean relative water content (RWC) of 96.85% under the same conditions. The positive effect of the chemical compounds (Chit and CP) on the physiological study indicators was reflected in the improvement of growth indicators, and tissue cultures growing under 25°C in a Chit-free media were achieved. The fresh media contained CP at a concentration of 2.0 mg L-1, amounting to 2.808 g. The increase in temperature at 35 °C for cultures growing in a media containing chemical compounds (CP+Chit.) at concentrations of 100 μM + 4.0 mg L-1 and 50 μM + 0 mg L-1, respectively, resulted in achieving the highest mean dry weight and calli growth of 131.3 mg and 0.541 respectively.