Based on the investigation on morphological and ornamental characteristics of 196 cultivars in Paeonia×suffruticosa Zhongyuan Group, an analysis on the correlation degree with the standard cultivar (SC) by grey system theory was carried out to evaluate and select cultivars for three different specialized purposes, landscaping, potted-plant and cut-flower production. The results showed that, the cultivars had a correlation degree over 0.7 to SC can be selected to propagate for landscaping, and ones had a correlation degree over 0.8 to SC can be selected for potted-plants and cut-flower cultivation. According to the conclusion above, 45 cultivars out of 196 investigated ones were recommended for production application, including 42 for landscaping, 20 for potted-plants and 12 for cut-flowers. Among all the recommended ones, 7 cultivars had the priority in production because they can meet all the requirements of landscaping, potted-plant and cut-flower production simultaneously. Fifteen cultivars were suited for landscaping as well as for potted-plant or cut-flower production. Three and 20 cultivars were only suited for potted-plant and landscaping respectively. Only a quarter of the total cultivars were selected, and the rest 151 were not well suited for mass production due to their unsatisfactory evaluation results.

Wild flowers,being colorful,beautiful and various,have higher ornamental values,and also have strong flexibility and resistance.They are very important flower resources and have important values in flower border design.On the foundation of investigation and study and the basis of the flower border design principles and some ornamental and ecological characteristics,the wild flowers investigated in Beijing Xiaolongmen Forestry Park in July,2011,have been analyzed and evaluated,and classified in three aspects,plant height,color and seasonal aspect,in order to provide reference and more materials for flower border design.

The genesis and differentiation into meristematic nodule of thin cell layer of(TCLs) petiole callus in modern tree peony 'Golden era' were studied.The results showed that there were four stages in the course of callus development,namely activation,division,formation and histodifferentiation.During activation,fascicular cambium cells were most notable,showing brown externally and bigger cells,clear and near-center nucleus internally.Meanwhile the starch metabolic enhanced.Cells kept division during the second stage division and led to the formation of callus in cambial area firstly and then in the region of cortex parenchyma cells.These callus tissues formed a compact cell cluster and the callus cells were characterized by dense cytoplasm,nucleus in center,small in volume and starch grains accumulated around the nucleus.However,callus proliferated at a slower rate during formation stage,only the peripheral callus cells which facing the medium kept division.At the last stage histodifferentiation,callus tissues differentiated into neoformed tracheary elements.Some of these tracheids organized as vascular centers and some specialized parenchyma cells could also act as centers.And then these centers were surrounded by loosely arranged,plastid-dense cell layers.This way,meristematic nodule formed which was thought to be potential in mass production.The result here can be used as a basis for further improvement of organ regeneration system for large-scale multiplication of tree peony.

Tree peonies (Paeonia sect. Moutan) are important ornamental plants, but their industrial exploitation is limited by the low yield of conventional propagation methods. In the present study, callus formation and development were successfully achieved through the selection of genotypes, developmental stage and position of explants, and plant growth regulators. Petiole layers collected during flowering as explants from seven different tree peony cultivars were cultured on Schenk and Hildebrandt (SH) medium supplemented with 0-2 mg l(-1) 2,4-D and subcultured on the same basal medium supplemented with 0.2-0.5 mg l(-1) 2,4-D and 2-6 mg l(-1) BA. The best performing cultivar was 'Golden Era', which produced a nodular structure within 90 days, while small calluses with low frequency were observed in 'Luo Yang Hong'. Explants taken from the basal or top petioles between flowering and 1 week after blossom fall showed negligible browning. In contrast, considerable browning was observed in middle petiole explants or those collected later than 1 week after blossom fall. The optimum medium for callus induction was SH medium containing 1 mg l(-1) 2,4-D. Callus proliferated into nodule structures on SH medium containing 0.2 mg l(-1) 2,4-D and 6 mg l(-1) BA for 'Golden Era' and 'Bartzella' and 0.5 mg l(-1) 2,4-D and 2 mg l(-1) BA for 'High Noon'. Nodules continued to proliferate under dark conditions. When the nodules of 'Golden Era' were transferred onto SH medium supplemented with combination of 0.25 mg l(-1) NAA and 0.5 mg l(-1) thidiazuron, and under continuous light condition shoot-buds differentiated from them. Histological studies suggested that callus derived from cambium and cortex parenchyma cells and then differentiated into nodular callus. Increased division of the epidermal and subepidermal cells of nodular callus led to shoot-bud regeneration.