Effects of Red and Blue LED Light at Night on Growth and Leaf Quality of Tea Plants

  Objective   Effects of red and blue LEDs applied at night in early spring on the growth and tea quality of Qianmei 601 (Camellia sinensis) were studied for the application at plantations in Guizhou.

  Method  Red and blue LEDs at a ratio of 0.81, 1.65 or 2.1 were shone on the tea plants at night for 21 days at a plantation for the experimentation.

  Result  The lighting promoted the bud and leave growth and improved the tea quality. Different red-to-blue light ratios produced different results. The treatment with a 0.81 ratio significantly increased the fresh leaf weight, bud density, total chlorophylls, total polyphenols, and free amino acids in the leaves and decreased the polyphenols/amino acids ratio as compared to control that grew under natural conditions.

  Conclusion   Supplementing light at night with red and blue LEDs at 0.81 ratio on tea plants in early spring when the sunlight and temperature are relatively low appeared beneficial for the biomass buildup and quality improvement.