Investigation On Cultivation And Physiology Of Four Important Begonia Species

Begonia is very rich in diversity and it has a huge number of species. It has been widely cultivated across the world due to its high ornamental values. However, there is a huge gap in utilization between China and the developed countries, such as Britain, the United States, Australia and Japan. The breeding and utilization of begonia started late in China, and has made a slow progress. Up to now, there have been only 27 begonia cultivars developed by Kunming Institute of Botanty, Chinese Academy of Sciences( CAS), such as ‘Kunming Bird', ‘Jianlü' and ‘Baiyunxiu'. Besides, these cultivars are hardly seen in the market and gargen. Therefore, much work is needed on development, utilization, cultivation and popularization of begonia resources.Begonia is commonly considered as a typical shade plant, and its growth is mainly influenced by several major factors, such as culture substrate, light intensity, temperature and relative humidity of its surrounding environment. There have been reports on production and breeding of begonias, but little on the effects of substrates and light intensity on its growth. How to choose substrate and light intensity to make different species or cultivars better growth remains unclear.In order to investigate the suitable cultivation substrates and light conditions depending on begonia species or cultivars, and to screen the optimum growth condition. Begonia cucullata Willd., B. wallichiana Steud., B. peltatifolia H. L. Li and B. ningmingensis ‘Ningming Silver' were used as material for conducting the potted experiment with treatments of light intensity and culture media. The main experimental results were as follows:(1) Imitating the indoor light condition, B. cucullata, B. wallichiana and B. peltatifolia were treated by artificial LED light at different light intensities to investigate the effects of light on plant growth and physiological indexes in the plant growth room. The results showed that the optimum light intensity for B. peltatifolia, B. wallichiana and B. cucullata were at 2000 lx, 2500 lx and 3000 lx, respectively, and therefore, these four begonias could be cultivated indoors under the suitable artificial lighting.(2) Four light conditions and four types of planting substrates were used in the potted culture experiment in a shadehouse to screen the optimum substrate and light intensity for growing B. ningmingensis ‘Ningming Silver'. According to the changes of growth indexes and chlorophyll contents, the mixture medium of leaf mold, perlite and pine bark with equal proportion and light shading 45% were the optimum condition for soilless culture of B. ningmingensis ‘Ningming Silver'.(3) In order to investigate possibility of the turf grass as alternative substrate for peat in begonia culture, the potted seedlings of B. cucullata were treated by eight types of planting substrates in shading 45% of shadehouse to evaluate its growth performance. It indicated that the substrate with turf grass : perlite : pine bark = 2 : 1 : 1 is the best and the turf grass can replace peat as culture substrate of begonias.