Soilless Culture Techniques Of Potted Seedlings Of Dendrobium Nobile

The one-year-old potted seedlings of Dendrobium nobile has been systematically studied by soilless culture in order to fred out a set of comprehensive techniques including optimum illumination,humidity,temperature,substrate,nutritional solution and method of nutritional solution irrigating.Adopting orthogonal experiment design,the ratio of nutrition element,concentration of nutrition,substrate,method of nutritional solution irrigating,time interval of nutrition application were tested.The ratio of nutrition element was wet at six levels,and the other at three levels.The optimum growthing environment of Dendrobium nobile seedlings was tested by the photosynthetic rate;the important factor of the soilless culture of Dendrobium nobile seedlings was decided by variance analysis of new leaves,bulbs,height of seedling, the content of chlorophyII,photosynthetic rate;the best statistical level was defined by Duncan's test;the optimum substrate and nutritional solution were determined by analysis of the major components;of which can offer the theory of the soilless culture of Dendrobium nobile.The analysis of light saturation point indicated that the photosynthetic rate of Dendrobium nobile was very low at no-increasing humidity condition.The increase of photosynthetic rate was stopped when the light intensity reached up to 17.9μmol m^-2·s^-1.thus the light saturation of Dendrobium nobile could be at considered 500μmol m^-2·s^-1,and therefore 30%overshadow net at noon of spring and 60%at summer in the north of china should be suitable.Analysis of the height of seedlings indicated that the important factor affecting the height of seedling was the interval days of nutrition application,substrate and the ratio of nutrition element.The other factors didn't reach significant levels.Analysis of the numbers of new leaves indicated that the important factor affecting the numbers of new leaves was the substrate,the ratio of nutrition element.The other factors didn't reach significant levels.Analysis of the number of the bulbs indicated that the important factor affecting the number of the bulbs was substrate,the ratio of nutrition element.The other factors didn't reach significant levels. Analysis of the content of chlorophyll indicated that the important factor affecting the content of chlorophyll was very little.