Impact of rejuvenation on physiological and biochemical status of different mango cultivars under sub-Himalayan Terai region of West Bengal

Twenty three years old five mango cultivars viz. Amarapali, Mallika, Himsagar, Fazli and Langra were rejuvenated (severe pruning) 150 cm from the ground level. Total phenol content, peroxidase, poly phenol oxidase, total carbohydrates and total free amino acids as well as total chlorophyll content were measured in 2019-2020 and 2020-2021 seasons in shoot buds with few leaves. The aforesaid parameters were measured before rejuvenation as well as four months after regrowth of pruned plants of different mango cultivars. Total phenol content was recorded higher (35.19 mg/g) in Langra and minimum amount of total phenols (35.50 mg/g) was recorded in Mallika before rejuvenation of plants. Chlorophyll content was decreased after rejuvenation of plants of all five cultivars, cv. Himsagar (1.08 mg/g) recorded higher chlorophyll content before rejuvenated plants. The total carbohydrate was not significantly varied before and after the rejuvenation practice and it was highest with cv. Himsagar before (0.80%) and after (0.74%) the rejuvenation. Maximum amount of total amino acid was recorded with cv. Amrapali (1.31%) before the rejuvenation and after pruning it was recorded higher on cv. Himsagar (2.0 %). Negligible difference recorded for peroxidase activity, maximum amount of peroxidase activity (0.37min/g) was recorded in cv. Himsagar before and after the rejuvenation and minimum (0.30 min/g) quantity observed in before and after rejuvenation plants of Mallika. The changes in PPO activity due to rejuvenation, the maximum activity of catechol oxidase (0.72) and laccase (0.62) were recorded in Langra.