【作者】 王文恩；

【导师】 包满珠；

【作者基本信息】 华中农业大学 ， 园林植物与观赏园艺， 2006， 硕士

【摘要】 利用不同剂量的⁶⁰Co-γ射线对野牛草、狗牙根和日本结缕草等三种暖季型草坪草干种子进行辐射，通过观测辐射后M₁代的发芽率、田间出苗率、幼苗生长情况等，研究辐射对这几种草坪草的生物学效应；初步确定了各品种辐射育种的半致死剂量；从狗牙根辐射M₁代中筛选出11个形态变异植株，并对这些变异植株进行了形态特征比较、倍性鉴定、过氧化物同工酶和ISSR分析。1辐射处理对3种草坪草种子萌发及田间出苗率的影响低剂量促进3种草坪草干种子的萌发，提高其发芽率，随着辐射剂量的增加，发芽率逐渐降低，野牛草、狗牙根和日本结缕草的临界辐射剂量（剂量率为1.0Gy／min）分别为300Gy、400Gy和450Gy。野牛草、狗牙根和日本结缕草的田间出苗率临界辐射剂量（剂量率为1.0Gy／min）分别为250Gy、350Gy和250Gy，低于临界辐射剂量时，随剂量的增大，田间出苗率增加，高于临界辐射剂量时，随剂量的增大，田间出苗率降低。2辐射处理对3种暖季型草坪草幼苗生长特性的影响不同的剂量处理，3种草坪草干种子发芽后根系和幼苗的生长差异显著。3个品种在主根长度、幼苗高度和鲜重方面均表现为先促进后抑制。对于野牛草和狗牙根而言，主根生长、幼苗高度和幼苗鲜重的临界辐射剂量都分别为300Gy、250Gy和200Gy。对日本结缕草来说，主根生长的临界辐射剂量为400Gy；幼苗高度的临界辐射剂量为300Gy；幼苗鲜重的临界辐射剂量为250Gy。初步确定野牛草、狗牙根和结缕草干种子辐射育种的半致死剂量分别为410Gy、450Gy和480Gy。3狗牙根变异植株的表型性状分析从辐射处理后M₁代的狗牙根植株中筛选出形态与对照有差异的植株11株，进行表型性状的测量，与对照和‘Tifway’、‘Tifgreen’进行比较分析，结果表明，各变异植株和其对照之间在叶片长度、节间长度和植株自然高度方面均有显著差异；HN004和其对照HN003的节间直径差异不显著，其它变异植株和其对照之间的节间直径差异均达到显著水平；叶片宽度除HN004和HN003之间，HN012、HN015和HN009之间差异不显著外，其它变异植株和其对照间差异均为显著水平。各材料的绿色期在242d-260d之间，其中变异植株HN015和HN016的绿色期最长（260d），HN010的绿色期最短（242d）。4 18个狗牙根材料的POD分析和ISSR分析18个狗牙根材料的POD分析表明：材料HN009和HN010、HN012和HN013的POD酶带特征完全相同；HN015和HN016的POD酶带在P8位点上的强弱不同、HN004和HN018的POD酶带在P5和P6位点上的强弱不同外，它们的酶带数和位点均相同；其它各材料之间酶带总数不同，在各个区域分布的位点及酶谱特征明显不同。除HN010和其对照HN009的酶谱特征相同外，其它形态变异植株和其对照之间的酶谱特征均存在明显差异。从38个ISSR随机引物中筛选出10个引物，对18个狗牙根材料的基因组DNA进行PCR扩增，并进行遗传相似系数与聚类分析，结果表明：HN003与HN007、HN005与HN007间、HN012与HN013之间、HN015和HN016间的GS值均大于0.8，这些材料之间的遗传相似性较高。HN001与HN014之间的遗传相似性最低，GS值仅0.46。筛选出的形态变异植株与其对照之间的GS在0.540-0.780之间，说明它们之间的遗传差异性比较明显。更多还原

【Abstract】 Using different dose of ⁶⁰Co-γto irradiate dry seeds of Buchloe dactyloides L., Cynodon dactylon L. and Zoysia japonica Steud., the irradiation effect and the half lethal dose of three Warm-season turfgrass species were surveyed by screening their germination rate, germination rate in field and seedling growth. 11 Variants of Cynodon dactylon L. were selected to compare with 2 commonly used cultivars, The growing and covering ability were characterised, and the ploidy level were measured by using the ploidy analyzer, and difference of peroxidase isozyme and ISSR were also analysed.1 The effect of irradiation on germination rate of the seed in the lab and the field of 3 turfgrassThe results indicated that irradiation of low dose can promote seed germination and increase germination rate, but the germination rate decrease with the increasing of the irradiation dose, the critical dose （dose rate is 1.0Gy/min） of Buchloe dactyloides L., Cynodon dactylon L. and Zoysia japonica Steud. is 300Gy, 400Gy and 450Gy respectively. The critical dose of field germination rate is 250Gy, 350Gy and 250Gy respectively. When the radiation dose below the critical dose was applied, the field germination rate icrease with the increasing of the irradiation dose, and the field germination rate decreased when the dose is over the critical dose.2 The effect of irradiation on seedling grow feature of 3 turfgrassThere are significant difference of taproot and seedling forming of the 3 species of turfgrass when the dry seeds were irradiated by different dose. The length of taproot, heigh and fresh weight of seedling of 3 species are all promoted at first and depressed later. The critical dose for taproot growth of Buchloe dactyloides and Cynodon dactylon is 300Gy, The critical dose for seedling heigh of Buchloe dactyloides and Cynodon dactylon is 250Gy, the critical dose for seedling fresh weigh of Buchloe dactyloides and Cynodon dactylon is 200Gy. The critical dose for taproot growth, seedling heigh and seedling fresh weigh of Zoysia japonica Steud. is 400Gy, 300Gy and 250Gy respectively. The half lethal dose of Buchloe dactyloides、Cynodon dactylon and Zoysia japonica Steud. is 410Gy, 450Gy and 480Gy respectively based on the difmition of the half lethal dose . 3 The analysed on Phenotypic Characters of Variants of Cynodon dactylon11 selected variants were screened in the phenotypic characters togather with the control plant ’Tifway’ and ’Tifgreen’, The results indicated that the difference of leaf length and internode length and plant height are all significant between variants and the control plant; the difference is significant in internode diameter between variants and the control except for HN003 and HN004; the difference is significant in leaf width between Variants and the control except for HN003 and HN004, HN012、HN015 and HN009. The green-periods range of 18 variants from 242 days to 260 days and the green-periods of HN015 and HN016 are longest and HN010 are shortest.4 The analysed of POD and ISSR of the 18 variantsThe results of POD indicated that the zymogram character is complete identical between HN009 and HN010, HN012 and HN013; The number of bands and locus is identical between HN015 and HN016 except for bands on P8 locus, between HN004 and HN018 except for bands on P5 and P6 locus; The number of bands and locus are obviously difference among the other materials. The difference of zymogram character are obvious between variants and the control plant except for HN010 and HN009.Ten primers were screened from 38 arbitrary primers of ISSR, 18 Genomic DNA of Cynodon dactylon materials were amplified, the results by GS and cluster analysis indicated that GS≥0.8 between HN003 and HN007, HN005 and HN007, HN012 and HN013, HN015 and HN016, and with high Genetic similarity. The Genetic similarity is lowest between HN001 and HN014 because their GS is 0.46. The Genetic Variability between variants and the control plant is significant.更多还原