Effects Of Mn On Tea Plant Growth And Tea Leaf Quality Of FuDingDaBai Cha And ZhuYeqi

Effects of Mn (MnSO₄) on tea plant growth and tea leaf quality of FuDingDaBai Cha and ZhuYeQi were investigated using solution culture and foliar spaying methods. The experimental results are as follws:Height of tea plants was inhibited when the plants cultured in certain Mn concentrations (≥1.0mg MnSO₄ · L^-1) for long time. Low Mn concentration (1.0mg MnSO₄·L^-1) promoted tea buds sprouting, but lowered buds number of FuDingDaBai Cha as concentrations of MnSO₄ in solutions higher than 15mg·L^-1. During long time cultivation, Mn inhibited tea root volume and activity, the effects of two varieties showed the same trend. Mn influenced net photosynthetic rate of tea plants, low Mn concentrations increased net photosynthesis at early stage but decreased that at later stage. In high temperature season, SOD, PPO, POD activities and MDA content in tea leaves improved with Mn addition, the Mn content in leaves also increased. After cultured for 143 days, Mn content in FuDing leaves reached the highest and also higher than that of ZhuYeQi. Mn helped Zn accumulation in FuDing leaves, while inhibited that in ZhuYeQi during the initial stage and increased their contents in leaves at later stage. This was also true for Fe content in ZhuYeQi.Low Mn treatment (1.0⁵.0 mg MnSO4 ·L^-1) increased yield of tea leaves after treated for 50 days, while high Mn treatment decreased obviously the yield of FuDingDaBai Cha and showed no noteble effect on that of ZhuYeQi. Spaying 0.2% 1.5% MnSO₄ solution also promoted tea leaves production. In addition, Mn inhibited tea polyphenol, and increased total AA and total protein in tea leaves and decreased the polyphenol and total AA ratio. In some extent adding low Mn helps to improve yield and qulity of tea leaves.