Allelopathic Effects Of Leaf Aqueous Extracts From Three Plant Species On Tea (Camellia Sinensis)

In this research, we studied the allelopathic effects of different concentrations leaf aqueous extracts(2.5 mg/m L, 5 mg/m L, 25 mg/m L, 50 mg/m L, 100 mg/m L) from Carya illinoensis, Castanea mollissima and Myrica rubra on the seed germination and seedling growth of tea(Camellia sinensis). The effects of the same concentrations of leaf aqueous extracts(5 mg/m L, 50 mg/m L, 500 mg/m L) from three kinds of plants on the shoot length, bud numbers and leaf areas, chlorophyll contents and physiological and biochemical indexes of potted tea were investigated. The contents of allelochemicals of juglone, chlorogenic acid and myricitrin from C. Illinoensis, C. Mollissima and M. rubrawere determined by high performance liquid chromatography(HPLC). Results showed that:1. The germination rate, germination index and vital index of tea seed were different influences by three kinds of botany. The growth of the tea seedlings were suppressed under high concentrations by the leaf aqueous extracts of C. illinoensis. The leaf aqueous extracts of C. mollissima had double concentration effects on root length of tea seedlings. The germination index, tea seedlings, fresh weight and dry weight were Promoted under low concentrations, whereas were inhibited under high concentrations of the leaf aqueous extracts of M. rubra.2. The allelopathic effects of growth index, chlorophyll content and photosynthetic index of tea seedlings were imparity under the same concentrations of three kinds of leaf aqueous extracts. Three kinds of leaf aqueous extracts had either promoting effects or inhibiting effects on the allelopathic effects of shoot length, bud numbers and leaf areas of tea seedlings. The chlorophyll contents and the photosynthetic index were consistented by the three kinds leaf aqueous extracts at the same concentrations and different processing time.3. The soluble Protein content of tea seedlings were reduced at first and then increased by three kinds leaf aqueous extracts at the same concentrations and different processing time. Howerver, the proline(Pro) content was increased at first and then decreased.4. The contents of allelochemicals of juglone or Myricitrin from C. Illinoensis, C. Mollissima and M. rubra were determined by HPLC. It showed that the content of juglone was 0.042 mg/m L from leaf aqueous extracts of C. Illinoensis. The contents of Chlorogenic acid were 0.614 mg/m L and 0.930 mg/m L from leaf aqueous extracts of C. Mollissima and M. rubra.These showed that three kinds of leaf aqueous extract concentrations lower than 50 mg/m L had no effects with tea, but in the actual production, the environmental impact many factors still need further field test verification.