| Cynodon dactylon[L.]Pers.is one of the most important grass species with high adaptability and demonstrated species diversity in warm-season turfgrasses.At present it is still not known about the systematic study through morphology and dissection, also its adaptive mechanism to drought stress is not clear at home and abroad. This study is divided into three parts, first, comparatively studied the morphology and dissection of the 110 populatios from different areas at home and abroad. Second, investigated the ecological distribution and the variation among different populations of Cynodon dactylon in Hainan. At last researched the anatomical mechanism to drought stress and selected drought-resistant genotypes.The main conclusions are as follows:1.There were large variations among the 110 populations of Cynodon dactylon in morphological traits. Greater variation were found in vegetative organs than in reproductive organs. The internode length of creeping stems vary most in quantitative character and the leaf hairiness vary most in qualitative characters. Significant variation was found in anatomical structures and the machinery organizes varied largest. The results of cluster analysis in morphology and dissection were similar with the distribution and ecotope of sample. Indicated that the two methods were practicable in dividing the populations of gramineae. It was found that there was great similarity in the samples from Hainan and Tifway(CK) and therefore has great potentiality in the exploitation of turfgrass.2.The result of the investigation indicated that the Cynodon dactylon of Hainan were abundant in germplasm resources. The elevations were between 0.5 to 715 meters, the pH of the soil were between 5.1 to 9.1.And the ecotope could be divided into these types:lawn in the riverbank, lawn in the sparse woods, mountainous and hilly area, lawn in the beach and other types.It was found that the size of the distributing area is proportional to the elevation. The dominant species in the community structure of the Cynodon dactylon were Axonopus compressus, Eleusine indica, Borreria stricta and Ipomoea pescaprae et al. The morphological traits of different population of Cynodon dactylon altered a lot between the condition of growing in the wild and the condition of growing in the field, and the variations were similar among populations. Additionally, the samples collected from beach variated greatly between wild culture and field culture, indicated that they were not suited to be transplanted to inland. Analyzed by the morphological traits,16 populations of Cynodon dactylon could be divided into 3 groups.The results of cluster analysis were similar with the ecotope of sample.The HNW0802 (Wuzhishan city, Hainan), HNBT0802 (Baoting county, Hainan), HNQH0801 (Qionghai city, Hainan) and HNHK0801 (Haikou city, Hainan) may be regarded as the excellent material used for the selecting and breeding of turfgrass.3.Explored the anatomical mechanism of Cynodon dactylon to drought stress preliminary.And selected 8 structural indexes in leaves as the drough-resistance indexes including:the thickness of cuticular, the thickness of epidermal cells, the area and density of stomata,the thickness of leaves in central vein,the thickness of leaves close to athletic-cell, the number of vascular bundles, the nunmber of strengthening tissues.The results showed that to evaluate the drought resistance from the anatomical structures-indexes and from the physiological indexes are similar. Demonstrated that it is practicable to evaluate the drought resistance from anatomical structures.It was inaccurate to reflect the drought resistance by the morphological traits of shoot. Thus comes to the conclusion that the morphological traits could only be a reference to reflected the drought resistance auxiliarily. Finally selected two genotypes which were more resistant to drought by evaluated the drought resistance among 10 samples from Hainan in this study comprehensively, they were HNBS0801 (Baisha county, Hainan) and HNLG0801 (Lingao county, Hainan). |
PDF Full Text Request