Effects Of Paclobutrazol On Ornamental Characters And Physiological Characteristics Of Rhododendron Hybrides

Rhododendron hybrids is a precious ornamental flowers, it is highly considered to has the value of ornamental and economic. The influence of different concentrations of paclobutrazol (PP333 ) on some physiological characteristics in leaves and petals of Rhododendron hybrides'Cosmopolitan'is systemly studied during flowering process, and other index about resistance which directly impact ornamental characteristics of Rhododendron hybrids is compared and analyzed, it is try to use the plnat growth-regulator paclobutrazol (PP333 ) to regulat the pot cultivation of Rhododendron hybrids, it can offer scientific base of application and promotion for landscape.The main results are follows:1. The height of plant and its crowns are differently inhibited under dissimilar PP333 concentrations, and the flowering rate is higher than in control during flowering process, but the flower diameter and color are not significantly changed, the results showed that the effect of PP333 on flower diameter and color is not significant. Comprehensively compared, it is concluded that the treatment of 900 mg/L PP333 has significant positive effect on controlling the heigh of plant and adjusting the plant type and regulating the flowering duration, it can relatively compact plant type, flower is imploded and flowering duration is prolonged.2. It can significantly increase the Chl a,Chl b,Chl and Car content in leaves of Rhododendron hybrids, so as to enhance the photosynthesis of plant.3. The content of light pigment in leaves is increased under dissimilar PP333 concentrations, so as the the photosynthesis of plant is enhanced and the content of soluble sugar in leaves is accumulated, the rate of decline in soluble sugar content in all treatment is sluggisher as the leaves senescence, it has significantly positive related to increase in concentrations.4. The degradation of protein in leaves is delayed under dissimilar PP333 concentrations, and the higher treatment has a remarkable result in long time. The protein content in petals is also relatively increased during flowering process, and the degradation of protein in petals in all treatment is sluggish as the petals senescence. It can provide more energy sources for delaying the senescence of petals, because dissimilar PP333 concentrations can maintain a high level of protein.5. The activity of SOD and POD in leaves and petals are significantly improved under dissimilar PP333 concentrations. The decline width of SOD and POD activity in leaves of all treatments are lower than control, and the maximum of SOD and POD activity in petals are also significantly improved, the higher treatment has obvious effect than lower treatment, it is concluded that the treatment of 900 mg/L PP333 has significant positive effect.6. The content of MDA has upward trend with the senescence of leaves and petals throughout the flowering period, but the MDA content of leaves and petals in all treatments are lower than control, it has significantly positive related to increase in concentrations. The production rate of O2- in all treatments is sluggisher than control, it dose not have significant difference during period of bud and flowering beginning, but the production rate of O2- in all treatments is sluggisher than control from the flowering period to aging period.Synthesized all the physiological indices, the treatment between 300 mg/L and 900 mg/L are suitable concentration, it is concluded that the treatment of 900 mg/L PP333 has significant positive effect, so as to delay aging of leaves and petals, it can provide the good basis of material for prolonging florescence and improving the quality of flower.