Effects of fluoride on growth, nutrient contents, catechins and aroma components in leaves of tea seedlings

A hydroponics experiment was carried out to study the effect of fluoride contents (0.1, 0.2, 0.3 mmol/L F) on dry matter, relative growth rate, nutrient element contents, catechins and aroma components in the leaves of tea seedlings (Camellia sinensis L. Pingyangtezao) in this study. The results show that with the increase of fluoride concentrations in culture solution, the accumulation of dry matter and the relative growth rate of tea seedlings decreased, the contents of P, Ca and F in the leaves significantly increased, the contents of N, K, Mg, Fe, Zn and HCO-3 in leaves decreased, and the content of Cl- keep roughly stable. The contents of four kinds of catechins (EGC, EC, EGCG and ECG), theanine and caffeine in the leaves dramatically decreased. When the F- level in the solution was 0.1 mmol/L, the contents of aldehydes, alcohols, esters and aromatic substances in the leaves decreased but when the F- level were at 0.2 or 0.3 mmol/L, the contents of these components increase, giving a improved taste of tea.