EFFECTS OF THE SPECTRAL ENERGY DISTRIBUTION OF RED, BLUE, AND FAR-RED LIGHT ON THE INDUCTION OF ANOECTOCHILUS ROXBURGHII (WALL.) LINDL. ADVENTITIOUS SHOOTS

摘要

The study investigated the effects of the light spectral energy distribution of red (R), blue (B), and far-red (Fr) light on the induction of Anoectochilus roxburghii adventitious shoots. Shoot tips with two internode sections without leaves were grown under light-emitting diodes (LEDs) at a photosynthetic photon flux density (PPFD) of 50 mu mol m(-2)s(-1) for a 12 h photoperiod. Three experiments were set up according to the different spectral energy distributions. In the first experiment, the treatments were 80% red + 20% far-red light (RFr41), 66.6% red + 33.3% far-red light (RFr21), 50% red + 50% far-red light (RFr11), and 100% red (R) light. In the second experiment, the treatments were 80% red + 20% blue light (RB41), 66.6% red + 33.3% blue light (RB21), 50% red + 50% blue light (RB11), 33.3% red + 66.6% blue light (RB12), and 20% red + 80% blue light (RB14). The third experiment was used as verification test. The treatments were the optimized spectral energy distributions from the first and second experiments, and fluorescent white lamps (W) were used as a control. The results showed that the induction and growth of the adventitious shoots were significantly promoted by adding far-red or blue light to red light. In the first experiment, RFr4linduced the highest number of shoots and starch content, RFr11 induced largest shoot diameter, soluble sugar, and sucrose contents than treatment R, the highest dry weight and health index were observed under RFr21 treatment, and the highest free amino acid content was observed under the R light treatment. In the second experiment, the number of shoots, shoot diameter, dry weight, health index, sucrose content, soluble protein, and starch contents were the greatest under RB41 treatment, the highest soluble sugar content was observed under RB21 treatment, and the highest free amino acid content was observed under RB14 treatment. In the third experiment, RFr21 induced largest shoot length, shoot dry weight, health index, and the soluble protein contents, RFr4linducedthe highest number of shoots and soluble sugar contents, and the largest shoot diameter was occurred under RB41 treatment.