Seasonal clonal variations and effects of stresses on quality chemicals and prephenate dehydratase enzyme activity in tea (Camellia sinensis)

Abstract

Seasonal and clonal variations in catechins, flavour component 2-phenylethanol and prephenate dehydratase (PDT) enzyme were studied in tea clones representing both Assam and China varieties growing in Kangra region of India. Catechins were analysed and quantified by HPLC, and 2-Phenylethanol was quantified by GC. Assam variety recorded higher amounts of catechins and PDT activity than China variety in all the three growth flushes. Activity of PDT and catechins content was high during mains growth flush followed by early and backend flush. 2-Phenylethanol content recorded higher levels in China variety compared to Assam variety, and higher content was observed in the early flush and decreased thereafter with progress in season in both the varieties. Decrease in catechins content, 2-phenylethanol and PDT activity was observed in the tea shoots infested by Exobasidium vexans over healthy shoots. Drought stress induced by withholding water for a period of 8 days caused initial increase in the contents of the catechins, 2-phenyethanol and PDT activity and decreased with 3 day onwards with an increase in the severity of water stress. Seasonal variations showed modulations in catechins and 2-phenylethanol in response to changing environmental conditions, suggesting that depending on the season there is higher flux of substrate towards the required product.