Effects Of Sugar And Dipotassium Hydrogen Phosphate On The Petal Senescence Of Dendrobium Cut Flower

Popular Dendrobium phalaenopsis has beautiful flowers and slender inflorescence. However, the abscission and wilting reduced the ornamental and economic value.In this study, we investigated the effects of dipotassium hydrogen phosphate and sucrose on the vaselife of Dendrobium'Sonia', and its petals senescence process, which including water metabolism, membrane peroxidation, anthocyanins and soluble sugar content, respiration and ethylene production. In addition, we observed microstructure and ultrastructure of each petal senescence phase. The results are as follows:1. Sugar brighten the floral's colore,0.2mol/L dipotassium hydrogen phosphate promote the process of the flowering, which extending petal life 50h. And the combination has slowed down the senescence phenomenon such as thickness reducing 0.15mm and dark colore, improved the viewing quality and vase life.2. Compared with control,0.2mol/L dipotassium hydrogen phosphate provided a relatively stable environment to maintain 5mg water. It could also promote membrane oxidation process 30mol·g-1mg-1min-1and a positive carbohydrate metabolism 0.06nmol/gFW.4% Sucrose didn't play a roll on membrane oxidation 40mg/100g and water balance, whereas the saturation of sugar can inhibit the metabolism of Carbohydrate updates and consumption.3. Dendrobium'Sonia' is ethylene-sensitive flowers. Each organ of the floral is able to release 3.46nl/g·h ethylene and gynostemium outputs the largest 2.52nl/g·h.0.2mol/L Dipotassium hydrogen phosphate reduced ethylene production 0.6nl/g·h and can inhibit respiration 0.5nmol/m2s at the early senescence stage.4% Sucrose can not reduce the ethylene production but the ethylene peak disappeared.4% Sucrose slowed down respiration rate. After mixing the two, the combinations taking their respective advantages reduced the amount of ethylene production 0.6 nmol/m2s and slowd down respiration 0.8 nmol/m2s.4. The detection of microstructure and ultrastructure of flower cells found out petal epidermal cells arranged in neat rows just at early stage and the size become bigger with the inclusion gradually increased. During the senescence period, the petals cell broken and inclusions released gradually.