Effect of temperature, photosynthetic photon flux, medium and fertilizer on growth of Oncidium

• Main Authors: Pei-Fen Tsai, 蔡佩芬
• Other Authors: Lee Nean
• Format: Others
• Language: zh-TW
• Published: 2000
• Online Access: http://ndltd.ncl.edu.tw/handle/88073483210061714682

碩士 === 國立臺灣大學 === 園藝學研究所 === 88 === ummary The cultivars of Oncidium Gower Ramsey, Sweet Sugar and Sharry Baby were used in this study to investigate the growth and flowering habits and research the effects of different day/night temperature and photosynthetic photon flux, growing media and slow-release fertilizers on growth of young plants. The photosynthetic rate were also measured in order to establishing the forcing culture model of Oncidium. Oncidium plantlets were removed from flask at plantlet stage (S1), unsheathing stage (S2) and axillary bud formation stage (S4). Plantlets formatted leaves mainly at the Plantlet stage. Plants with 3pseudobulbs have flowering capacity. Plants with 4 pseudobulbs about 2 years old removing from flask could productexcellent inflorescence. Flowers were harvested at peak from Apr to May and Sep to Dec. The qualities of spring flowers were better than autumn flowers. Light and temperature affected plant growth and axillary bud formation. The optimal day/night temperature for young and middle size plants was about 20-25℃. The cultivar of Sharry Baby were more sensitive to high and low temperature. Plants suffered chilling injury at 15/13℃ treatment and got sun burn at 35/30℃ within 1week. The optimal temperature for CO2 uptake at range of 16-22℃. With the decrease of temperature the CO2 uptake rate and stomatal conductance increased significantly. The CO2 uptake rate was about 3.5-5μmolm-2s-1 from 16 to 22℃. When the temperature reached to 28-30℃, the CO2 uptake rate was about 0.5μmol.m-2s-1. Hence, the optimal temperature is between 20-15℃. The growth and CO2 uptake rate increased with the increase of light intensity between 40-200μmol.m-2s-1. The optimal light intensity for Oncidium young plants was between 150 and 200μmol.m-2s-1. The requirement of light intensity for Oncidium mature plants was higher than young plants, about 200-300μmolm-2s-1. Compared with these 3 cultivars, Gower Ramsey required more light than Sweet Sugar and Sharry Baby. Indeed, the CO2 uptake rate was mainly affected by environmental factors such as: light and temperature, but rarely affected by internal factors such as: plant age, leaf position and developmental stage. Oncidium young plants grew better when cultured in sphagnum and sphagnum mix and given a full strength of Johnson’s solution once 1 week. Slow-release fertilizer Osmocote (14-14-14) released faster than Hi-control, so that should reduce the dosage. The optimal EC range was between 0.5-1.5 mS/cm. The pH tolerant ability of Oncidium young plants was from pH 3 to pH 6. Briefly, the Oncidium plantlets should be cultured under after removing from flask. Yong plants grew well when grown in growing medium with high water capacity and given liquid fertilizer. The slow-release fertilizer was more convenient, but should reduce the dosage. Suggested that the optimal dosage of Osmocote was 3-6g/L, the Hi-control is 6-8g/L.