Abstract: Vegetatively propagated 10-month-old tea [Camellia sinensis (L.) O. Kuntze cv. Ruixiang] seedlings grown in pots were fertilized three times weekly for 26 weeks with nutrient solution containing 0, 100, 400, 800 or 2β000βμmol·L^-1 potassium. The effects of different potassium concentrations on the nutritional elements (N, P, K), biochemical and aroma components of tea seedlings were studied. The results showed that the tea plants exhibited potassium deficiency when the potassium concentration was 0 or 100βμmol·L^-1. The potassium contents in the mature leaves of the tea plants were 5.26βmg·g^-1 and 5.91βmg·g^-1, correspondingly. The K-deficiency decreased the root and shoot biomasses, but increased the the ratio of root to shoot. Leaf K content was positively correlated with N and P levels (Y_N=1.045X+11.9065, R²=0.8167. Y_P=0.3075X–0.5706, R² =0.9146 ). Results also showed that K-deficiency decreased the contents of amino acid, caffeine, water extract and EGCG, but increased the contents of tea polyphenol, catechins, EGC, EC and the ratio of tea polyphenol to anmin acid. The contents of arginine, theanine and glutamic acid were significantly decreased in the K-deficient leaves as compared with leaves under normal potassium supply (2 000 μmol·L^-1), which decreased by 86.96%, 72.46% and 40.43% respectively. Aroma component analysis showed that the K-deficient leaves had lower alcohols, aldehydes and esters. Potassium deficiency had a negative effect on the aroma quality of tea leaves.

Key words: tea plant, K deficiency, biochemical components, aroma components