Nitrogen metabolism of detached tea shoots I.—Changes in amino‐acids and amides of tea shoots during withering

Amino‐acids and amides of fresh and withered tea shoots have been estimated by a spectrophotometric method following separation on chromatograms. During withering, asparagine, glutamine, aspartic acid, glutamic acid, leucine (isoleucine), phenylalanine, valine and serine accumulate as a result of protein breakdown. The amino‐acid content of leaf plucked in the evening after an active period of photosynthesis is generally higher than that of leaf plucked in the morning. When leaf is stored under reduced pressure, glutamine content decreases; asparagine does not accumulate and relatively smaller amounts of other amino‐acids are formed. Amino‐acids are partially used up during the manufacture of black tea.