Taxonomic Treatments Of Camellia Section Tuberlata And The Evaluation Of Their Germplasm Resources

The section Tuberculata Chang, belonging to family Theacea, genus Camellia, only distributed in China, represents a good example of a taxonomic group in the genus Camellia with controversial circumscription. This section was charactered by the tuberculate presented on the ovaries and seeds, and it was therefore considered to be orignal groups in Camellia. At present, the taxonomic treatment of the section Tuberculata is still ambiguous, which causes great inconvenience to protection of the germplasm resources and the development and utilization.In present study, the leaf epidermial micro-morphology and comparative anatomy of 18 disputed species of the section Tuberulata (Camellia, Theaceae) combined with their fourier transform infrared spectroscopy (FTIR) have been conducted in order to investigate interspecific variations which were useful in species taxonomic treatment. Based on the taxonomic treatments, chlorophyll fluorescence technology was used to study leaf chlorophyll fluorescence characteristics of seasonal changes of Tuberculata speices, and evaluate the their growth adaptation ability. FTIR was used to analyze the Phytochemical perspectives of the Tuberculata species and tea (C.sinensis) in order to evaluate their values of the application. Our results were as follows:(1) Results of the study showed that there was considerable anatomical variation between the 18 species studied and some anatomical characters had diagnostic value in the section. The epidermal cells of Tuberculata were usually polygonal or irregular in form, with anticlinal walls straight to curved, or sinuous. The pattern of anticlinial wall varied not only in different species but also between adaxial (Ad) and abaxial (Ab) epidermis of the same species. All species in section Tuberculata were hypostomatic, and the stomata were all of the anisocytic type. All the leaves in the sections were bifacial and were composed of wax, epidermis, palisade parenchyma, spongy parenchyma, and vascular tissue. A multiple epidermis was found in most species. Sclereids were found in all 18 species studied. These results also supported Ming's merging some species in Tuberculata. All species were marked by glands and crystals, except C. ilicifolia, which supported Chang's regarded C. ilicifolia as a sole specie. Furthermore, leaf epdermic and anatomical characters were found slight difference among Tuberculata species, which indicated that Tuberculata was a natural group with close genetic relationship.(2) Multivariate analysis (PCA and Cluster analysis) of leaf FTIR data in Tuberculata showed a visualization of the degree of affinity among the species in this section. PCA and Cluster analysis showed that C. ilicifolia became significantly distance from other 17 species. These results did not support Ming and Zhong's conclusion in transferring C. ilicifolia Y. K. Li ex H. T. Chang from the section Pseudocamellia in Chang's classification into the section Tuberculata. Multivariate analysis of leaf FTIR data in Tuberculata showed that it permitted a visualization of the degree of affinity among the species, which supported Ming's mergering of Tuberculata species.(3) Our study indicated that the combination of characters based on leaf comparative anatomy and FTIR analysis and biogeographical distribution were useful in species revision. The results determined 11 species including C. tuberculata Chien, C. rhytidocarpa Chang et, C. rhytidophylla Chang Liang, C. anlungensis Chang, C. rubituberculata Chang, C. acutiperulata Chang et Ye., C. neriiflolia Chang, C. obovatifolia Chang, C. rubimuricata Chang et Z. R. XU, C. parvimuricata Chang, C. pyxidiacea Z. R. Xu et al. in the section Tuberculata. Moreover, our study also supported that Chang transfer C. ilicifolia Y. K. Li ex H. T. Chang from Tuberculata into the section Pseudocamellia.(4) Leaf light-response curves of chlorophyll fluorescence, daily changes of seasonal Yield and determination of relative content of chlorophyll indicated C. rhytidophylla,C. rubituberculata,C. tuberculata,C. rhytidocarpa had a good ability to utilize light energy. Therefore, they could well adapt to grow in the region. Our studies also indicated that the ability of photosynthesis in C. neriiflolia,C. obovatifolia,C. parvimuricata were significantly inefficient, which suggested that these three species were not suitable for growth in the region. Thus, we thought that the appropriate treatment of the shade would help Tuberculata plants grown better.(5) FTIR spectra of tea and Tuberculata species showed that carbohydrates and polysaccharides ( 3400 cm^-1 ,1150-1030 cm^-1) in Tuberculata species leaves were more abundance than that in tea, indicating that vascular tissues of leaves of Tuberculata species developed well than tea. Furthermore, Tuberculata species had rich absorption peaks in 1800-1200 cm^-1, indicating they also had rich active ingredients of tea. Therefore, they could be considered as a plant material extracted the active ingredients.