Tissue culture and rapid propagation of Reynoutria japonica Factors Affecting High-frequency Induction of Hair-like Roots of Reynoutria Japonica Houtt. Centrifugation Purification and Protoplasts Electrofusion of Reynoutria japonica Diurnal Variation of Eco-physiological and Photosynthetic Characteristics of Reynoutria japonica Effects of UV-C and Salicylic Acid on Resveratrol and Polydatin Induction in Leaves of Reynoutria japonica