Physiological and biochemical changes with special reference to mangiferin and oxidative enzymes level in malformation resistant and susceptible cultivars of mango (Mangifera indica L.)

Changes in biophysical attributes, mangiferin and polyphenol oxidase (PPO), catalase and peroxidase activities in malformation resistant mango cultivar Elaichi were studied at various stages of flower development and compared with susceptible cvs. Amrapali, Beauty Mc-lin and Dashehari. Accumulation of mangiferin was maximum (96.0 and 108.0 mg g⁻¹ FW) in Elaichi prior to flower bud differentiation (September) and at full bloom (February), while these were minimum (59.0 and 74.0 mg g⁻¹ FW) in susceptible cv. Beauty Mc-lin. Mangiferin promoted vegetative growth and exhibited inhibitory role on the occurrence of malformation. It was also found that the resistant cultivar had highest activity of PPO as compared to susceptible ones. There was no significant difference in the enzymes catalase and peroxidase activity at early stage of flower differentiation but at flower bud burst stage the catalase activity was enhanced significantly in cv. Elaichi (25.28 unit min⁻¹ g⁻¹ FW) in comparison to Amrapali (16.20 unit min⁻¹ g⁻¹ FW), Beauty Mc-lin (18.39 unit min⁻¹ g⁻¹ FW) and Dashehari (17.50 unit min⁻¹ g⁻¹ FW). The resistant cultivar had high leaf temperature (30.30 °C) and diffusion resistance (476.14 m mol m⁻² s⁻¹) during the flowering but the rate of transpiration and relative humidity (RH) were high in susceptible cultivars. Results of the present study clearly indicate that level of mangiferin could be considered as a potential biochemical indicator for screening mango genotypes to malformation.