Effects of plant growth regulator on growth and development in Cymbidium sincence

• Main Authors: Jia- Wei Jian, 簡嘉維
• Other Authors: Shiou- Jen Huang
• Format: Others
• Language: zh-TW
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/46666827714549027314

碩士 === 國立宜蘭大學 === 園藝學系碩士班 === 100 === Cymbidium science ‘Ruihua’,‘Gold Huashan’ and ‘Pacific Ocean’ was used in this study. The objective is to investigate the effects of different concentration of Paclobutrazol (PBZ) (0、25, 50, 100, 200 and 400 ppm)、6-BA (0, 500, 1000 and 2000 ppm) and chitosan (1 mL．L-1 and 2 mL．L-1), and plants were soaked, soil drench and foliar application of different treatments on plant growth and development. Cymbidium sicience 'Ruihua' applying different concentrations of soak treatments, plant had the most significant difference, the higher concentration, the less elongation, but there was not a significant response for Cymbidium sicience ‘Gold Huashan’. PBZ drench had a greater retarding activity on leaf elongation than spray. A 400 ppm PBZ drench three times resulted in the shortest plants , which had the lowest leaf elongation count（0.75 cm）. It was apparent that 400 ppm drench and spray treatments with PBZ decreased leaf elongation of Cymbidium sicience ‘Gold Huashan’ over the control , it was also observed that Cymbidium sicience ‘Pacific Ocean’ plants leaf elongation decreased with increasing concentration of PBZ drench, plant drenched with PBZ 400 ppm after 105 days, leaf elongation was inhibited 70％ than control, and plant were sprayed 400ppm PBZ after 49 days reduced leaf elongation only 26％, but there was no significant difference between control and sprayed with PBZ 50 ,100 and 200 ppm . Flower stalk was significantly decreased with increased dose of PBZ , On the contrary, increased flower diameter only at the highest drench concentration, but there was no difference at flower diameter and color. It was investigated the photosynthesis enhanced was accompanied by higher leaf temperature all year through, and the net photosynthetic rate was greatest at 200ppmPBZ. During the first 20weeks after treatment, PBZ acceleration of the net photosynthetic rate than those untreated plants, but decreased the activities of photosynthesis as well as control in November. Results showed 6-BA applied to the plants, there were no significant effects between mother’s pseudobulbs thickness and width, but the application of 6-BA led to a decreasing of shoot’s pseudobulbs width and thickness, especially when applied as a soil drench. Drench application of 6-BA at dose of 500 ppm resulted in significant increasing in the number of lateral shoots and plants had no visual differences in the structure of roots , plants were sprayed 1000 ppm PBZ had less lateral shoots than former. Plants treated with 500 ppm and 1000 ppm of BA were significant increasing the number of lateral shoots（2.3 and 1.8 shoots/pot） than control（1.2 shoots/pot）, it was also observed from the other different treatments（1.2 shoots/pot）. Additionally, plant drenched with 500 ppm 6-BA was more effective inducing on the mother’s pseudobulb latent buds (0.8 buds of per pseudobulb), but no effects of control and spray applications . Cymbidium sicience ‘Gold Huashan’ application of PBZ could cause suppressing latent buds inducing and led plants to a poor resistance from plant dieses , Combing 100 ppmPBZ, 500 ppm 6-BA and 2 mL．L-1 chitosan had been effective in promoting the resistance from diseases, and Cymbidium sicience ‘Pacific Ocean’ was applied 50 ppm PBZ, 500 ppm 6-BA and 2 mL．L-1 chitosan before latent buds emergence, the treatments have high net photosynthesis and best foliar variegation, suggesting that weekly application chitosan continued was most effective at pathogens control.