Study On Media And Nutritive Regulation Of Cyclamen In The Protected Cultivation

Cyclamen (Cyclamen persicum L.) belongs to Cyclamen genus, Primula malacoides Franch family. Because of its special ornamental and horticultural characteristics, such as unique flower-shape, variegated colors, long-lasting flower-periods, suitable for potting, and the professional potting system for some different kinds of Cyclamen varieties in modern greenhouse have been setting up for a long periods in Europe, U.S.A and Japan. The cultivation history of Cyclamen in China is so short that the quantity of cultivars with high production and excellent quality is very small. And the researches of production techniques in modern facility greenhouse were only studied preliminarily. All the shortcomings, such as the low rate of superior product, high-production costs, the defects of production techniques, would become more and more outstanding in the process of large scale production.The paper discussed the influences of Cyclamen cultivar NP3 growing in different cultivated media under protected cultivation and got the best medium. Some media were taken as test materials, such as sedge peat, perlite, vermiculite, coconut coir, yellow soil, reed residues, etc. By using different mixed ratio, 7 kinds of mixed medium formula were preliminary selected to Cyclamen NP3 for mixed media screening test. The overground and underground parts of the plant was researched. The results showed that No.6 mixed medium was the best suitable formula (the sieving sedge peat which came from China, vermiculite, perlite, the proportion is 5, 4 and 1.) for modern large scale production in Greenhouse.The absorption and accumulation rules of N, P, K were researched in three cultivars of Cyclamen (S3, Ml, and NP3) which were grown in the optimized medium, the results showed that:1. Their amounts of dry matter accumulation and different parts of plantlet were tested in different growth and development stages. The results showed that the dry matter accumulation of Cyclamen S3 was the least. Even the growth has to stagnate for dormancy, the nutrient elements of absorption and accumulation of Cyclamen's underground-parts still kept on. In September, Cyclamen's aerial parts began to vigorous growth. At the same periods, the accumulation of dry matters in Cyclamen's aerial parts would reach the peak. The dry matter of S3, in this period would account for 73.15% of dry matter accumulation in the whole growth and development stages. In addition, 55.97% of Ml and 69.64% of NP3.. The cultivar Ml would begin the vigorous growth more earlier than the other two cultivars,. After December, the accumulation and consumption in plant would reach the balanced states.2. The order form high to low of distribution proportion of dry matters in different organs was respectively leaves-parts, root-parts, corm-part. In different growth and development stages, the distribution ratio of dry matters in different parts would have some changes. Basically, the leaves-parts would account for 80-83%, corm-part with 4-6%, and root with 6-9%.3. The absorption and accumulation rules of nitrogen, phosphorus and potassium were researched under protected cultivation using S3, Ml and NP3. In the early days of the experiment, the demand for potassium was the most, followed with nitrogen and phosphorus. There existed great differences among the three cultivars. Before the last ten days period, nitrogen, phosphorus and potassium absorption of S3 was 0.57g per plant, 0.085g per plant, 0.533g per plant. And Ml was 1.197g per plant, 0.218g per plant, 1.271g per plant. NP3 was 0.986g per plant, 0.171g per plant, 0.97g per plant. Among the three cultivars the absorption ratio of nitrogen and phosphorus remained the range of 5.5:1～6.5:1. The accumulation ratio of potassium and nitrogen remained 1:1. Three elements absorption of different cultivars existed differences. After September, nitrogen absorption of S3 and NP3 increased significantly, and reached the maximum in the growth peak,. Maximum nitrogen absorption of Ml appeared earlier than S3 and NP3 for about one month. Maximum phosphorus absorption of Ml and S3 appeared during the end of August to the early of October, absorption of NP3 reached maximum during the end of October.4. Based on that, there are some suggestions for fertilization measures in the protected cultivation. Controlled-release fertilizer application was not suitable for S3 and Ml until the end of August Fertilization rate should be improved in September and October, especially nitrogen fertilizer, which is benefit for vegetative growth, at the same time, amount of phosphate fertilizer and nitrogen fertilizer should be increased. The peak phase of flower bud differentiation was at November, increasing application of potassium fertilizer should be emphasized and the amount of potassium fertilizer ought to be increased 1-2 times. The amount of nitrogen fertilization could be controlled to some extent, so that flower would be bright and flourish. Finally, keep the three elements proportion invariant. NP3 was a little special, during the whole summer, the absorption of nitrogen, phosphorus and potassium remained at relatively high level, increasing fertilization times would be helpful to meet the nutrition demand. During September and October, fertilization rate should be improved, especially nitrogen fertilizer, at the same time, the amount of phosphate fertilizer should be increased to some extent. During November, the amount of potassium fertilizer should be increased 2-4 times, and nitrogen fertilizer should be controlled.All the results are of important theoretical significance for Cyclamen protected cultivation, scale production and provide references for fertilization.