Study On Drought Adaptability Of 7 Roegneria Species

18 wild germplasm materials of 7 species of Roegneria C.Koch from different habitats were studied in the thesis. Adaptability was studied according to biological characteristics, production performance, leaf anatomy at Xilin Gol city in Inner Mongolia steppe(field station of grassland resource ecological monitoring and assessment in Taipusi county of CAAS), Drought stress was studied at seedling stage in greenhouse of Inner Mongolia Agricultural University.The main results were as follows:1. 18 wild germplasm materials of 7 species of Roegneria C.Koch were evaluated by biological characteristics, production performance in dry conditions in the field (Annual amount of precipitation was approximately 260mm), phonological observation showed these materials could finished reproductive period,and all past winter. Plant height, leaf area and root length was significant different in each period. Biomass (fresh and hay) of R.stricta,R.varla,R.melanthera were higher. R.turczaninorii var. turczaninovii and R.ciliaris have relatively high seed yield. Comprehensive evaluation analysis of 18 materials showed that there were 5 copies of the best adaptation, 9 medium, 4 poor. Clustering analysis displayed 3 materials of R.dura and 4 material of R.nutans together as a class, and other materials cluster together.2. 6 typical Roegneria C.Koch materials were selected to the observation and analysis of leaf anatomical structures. Firstly, the aged Leaves were cut into slices by using scraper and paraffin section. 4 phenotypic traits of leaf lower epidermis were observed under optical microscopy, and 17 quantitative traits of leaf cross-section and leaf lower epidermis were measured. ANOVA analysis showed leaf midrib thickness, leaf thickness, upper epidermis thickness,stomata index and so on were significant or extremely significant among the 6 species. Principal component analysis displayed the mostly information of 17 quantitative indicators focused on the first three main component which were function structures of water storage and transport, leaf epidermal characteristics structures and structures to resist stress. 7 anatomical characters that was drought-related were selected as basis for evaluation of drought resistance, the order of drought resistance of 6 species was: R.melanthera > R.stricta > R.turczaninorii var. turczaninovii> R.varla > R.ciliaris > R.nutans.3. 7 typical materials were selected to successive drought stress on seedling stage by potted plant to simulate soil drought condition. The results showed that with the days of drought stress increased, soil relative volumetric water content(SVWC),leaf relative water content(RWC) and chlorophyll content were significantly decreased (p <0.05), on the contrary , the withered rate,praline(PRO) content,cell membrane permeability(REC) and malondialdehyde(MDA) content were significantly increased (p <0.05), POD activity and SOD activity increased at the begining and then changed differently. Correlation analysis showed that between indicators were significantly or highly significantly correlations except the SOD activity. The subordinate function comprehensive evaluated drought resistance of 7 plants, their drought-resistance order was R.melanthera > R.nutans > R.stricta > R.ciliaris > R.varla > R.dura >R.turczaninorii var. turczaninovii.R.melanthera was evaluated comprehensive in all aspects of the experiment showed great adaptability, so it can be selected as high-quality drought tolerance forage.