Abstract:

The purpose was to study the effects of different fertilization on growth and photosynthetic physiology of Oncidium, find out the best way of fertilization in the vegetative growth phase. The studies on parameters of photosynthetic physiology and growth were carried on potted Oncidium by five different fertilizing methods at seeding and stocking stage. It was showed that in the vegetative growth phase, different treatments had obvious diversity in the indexes of plant height, dry material accumulation, content of chlorophyll of the leaves and its photosynthetic physiological characteristics. We found out that at seeding stage spraying or irrigating specialty fertilizer at low concentration, irrigating specialty fertilizer at medium concentration, can obviously increase the plant high, dry weight of the leave, net photosynthetic rate, stomatal conductance, Intercellular CO2 concentration, transpiration rate, and so on. At stocking stage, irrigating specialty fertilizer at medium or low concentration，spreading slow release fertilizer, can obviously increase the plant high, diameter of bulb, dry weight of stem, net photosynthetic rate, stomatal conductance, carboxylation efficiency, and so on. The best fertilizing method at different stages of Oncidium: at seeding stage only spray or combine of spraying and irrigation of specialty fertilizer at low concentration; at stocking stage, irrigate specialty fertilizer at medium concentration or irrigate specialty fertilizer at low concentration together with spread slow release fertilizer.