Fresh leaves of tea cultivar Shuchazao were harvested from five different stages of shoot development including single-bud(SB),one leaf and one bud(BL1),two leaves and one bud(BL2),three leaves and one bud(BL3)and mature leaves(ML,including five leaves).The contents of tea-specific components,including caffeine,catechins and amino acids,in tea leaves were extracted and analyzed using the HPLC technique.The results showed that the content of caffeine in the buds in BL3 stage was generally the highest,while it did not change much in SB,BL1 and BL2 stages.The content of caffeine in the leaves at the same leaf-age was similar in five different development stages.The total contents of catechins in the first leaf were higher than that in the buds in all five development stages,and it was the highest in the first leaf at BL1 stage,but it decreased with the increase of the leaf-age.As far as the monomeric catechins were concerned,non-ester type catechins and ester type catechins can be detected in the buds or leaves in the five development stages.The majority of catechins were epigallocatechingallate(EGCG),which showed a similar variation tendency as that of total catechins.However,the contents of non-ester type catechins such as epicatechingallate(EGC),epicatechin(EC) and gallocatechin(GC) were higher in buds than in leaves,which were opposite to the content variation trends of ester type catechins in the course of shoot development.Theanine was the major amino acids in all development stages of tender shoots,and its content in the stage of single-bud was the highest.The content of theanine in buds was three or four times higher than in leaves,and the older the leaf-age was,the less theanine existed in the leaves.
Jing ZhangHua YangChao-Ling WeiYu-Ling TaiQi ChenXiao-Chun Wan
