Effect Of Media And Nutrient Solutions On The Growth And Development Of Nobile-type Dendrobium

Nobile-type Dendrobium is a newly-arised potted flower with a large market potential. Sphagna is the main medium for Nobile-type Dendrobium, but is costly and leads to environmental damage during the acquisition process. In this study, the growth and development of Nobile-type Dendrobium were compared using the morphological and physiological characteristics. The Nobile-type Dendrobium palnts were treated with different media and nutrient solutions of N, P, K ratios and N sources. The aim was to select a more appropriate alternative to sphagna. Also, the effect of the media and nutrient solutions is discussed. This will provide the basis for rational fertilization for the substrate-soilless culture. The main conclusions are as follows:(1) Evaluation System on the Varieties Index of Nobile-type Dendrobium:Six indexes can be used to characterize the flower.1 total flower numbers; 2 flower diameter; 3crown width; 41eaf numbers on one Pseudobulb; 5color; 6 pseudobulb diameter that can be used for evaluating different varieties. And For the same varieties, the former forth is the same with two different indexes:branches number and flowers’uniformity.(2) Effect of Media and Nutrient Solutions on the Growth and Development of Nobile-type Dendrobium The result of some media and nutrient solutions’effect on the growth and development of Nobile-type Dendrobium showed that:Sphagna had significant effect on the plants’vegetative growth than on the flowering. The plant takes a significantly higher quantity and uniform flower planted in medium coco peat:bark: perlite= 2:1:1, though its vegetative growth is weaker than sphagna. Comprehensive media’s cost factors, the medium coco waste:bark:perlite=2:1:1 may be a good substitute for sphagna.Plants’vegetative growth was vigorous under the Hoagland and Snyder’s solution (1933) (N1), but it resulted in less flowers and smaller diameter. The new-bulbils’growth was not good in the Phalaenopsis solution (N2) whose nitrate was reduced and the P, K ratios increased; however, the flowering quality was best. The survival rate of the plants growin in the nutrient solution (N3) with higher P, K ratio and application had smallest flower diameter and lower flowering uniformity. The plants treated with (N4) nutrient solution which increased the N and K application and P’s maintained were taller with largest diameter. The plants treated with N4 showed better vegetative and flowering performance when N, P, K ratio was15:2.68:7.07and the amount of application was 17:1:7.(3) Effect of Different Nitrogen on the Growth of Nobile-type Dendrobium:As the NH4+—N ratio increased, the plants planted on the sphagna medium showed good morphological growth characteristics in the early spring. In high ammonium (75:25) and the total ammonium nitrogen (100:0) treatment, the plants grew well and had higher chlorophyll content, larger root activity, taller plant height, more node number and biomass. And the plants had slow growth in ammonium N (25:75 and 50:50). No significant differences were found in plant morphology under different fertilizer application amounts but the chlorophyll content in the plants increased, root activity and the soluble sugar content reduced with increasing amounts of application. Nobile-type Dendrobium is a C3 plant and with the nature of CAM plants. With the increasing of NH4+—N, the photosynthetic rate was not affected at low temperature. Ammonium application should be avoided at high temperature period (from June 15)(4) Effect of Nutrient Deficiency on the Growth and Development of Nobile-type Dendrobium:The Plants’small leaf area, yellow leaves were due to N deficient which was beneficial to plant roots aborsing K, P, thus promoting flowering plants. Lack of P may cause late formation of leaves, thin and high pseudobulb. Lack of K is mainly affected in the tip necrosis of old yellow leaves, the plants cannot bloom. The plants showed significant early necrotic new bulbils in the absence of Ca:it had the lowest survival rate and least dry weight. In this study, no significant growth and development of Nobile-type was noticed in plants lacking Mg.(5) Nitrogen was the most important element for plant growth because it had effect on the plants photosynthesis; P and K affected the quality of the spring flowering of Dendrobium. The concentrations of N:15mol/L, P:2.5mol/L and, K:6.5mol/L applied in the 8d at a rate of 10ml and30ml caused normal growth and development.in the biennial and the four-year old plants.