【摘要】 本文观察了数种高能重离子辐射处理水稻干种子的生物学效应。结果表明,与具低传能线密度（LET）的⁶⁰Co-γ射线相比,这些具高LET的重离子能更有效地抑制受照射种子萌发长出的幼苗的生长,诱导根尖细胞和花粉母细胞的染色体畸变和微核形成,降低当代植株的结实率,并诱发后代出现形态性状及农艺性状的变异。在一定剂量范围内,辐射诱导的上述数种生物学效应与吸收剂量间呈线性关系。根据剂量一效应关系曲线,估算了重离子辐射的相对生物学效率（RBE）及作用截面。分析了辐射诱导的突变率及突变谱,确定了能量为400MeV/u的氩离子束的最佳诱变剂量为90—100Gy,用此剂量处理具特殊香味的广东籼稻地方品种“香占”,获得了性状明显改良,而又保留原种优点的3个稳定突变株系,已经M₅代品比测产检验,证明重离子辐射在品种改良的应用上具有良好潜力。更多还原

【Abstract】 Genetic and developmental effects of heavy ions in rice were investigated. Heavy particles with various charges and energies were accelerated at the BEVELAC, Lawrence Berkeley Laboratory, USA. The effectiveness of high-LET heavy ion in (1) inhibiting seedling growth, (2) reducing plant fertility, (3) inducing chromosome aberration and micronuclei in root tip and pollen mother cells of the first generation plants developed from exposed seeds, and (4) inducing mutation in the second generation, were greater than that of low-LET gamma rays. All effects observed were dose-dependent; however, an optimal range of doses existed for inducing certain types of mutation, For example, for argon ions (400 MeV/u) treatment at 90-100 Gy, several valuable mutant lines with favorable characters, such as semidwarf, early maturity and high yield ability, were obtained. Experimental results suggest that the potential application of heavy ions in crop improvement is promising. RFLP analysis of two semidwarf mutants induced by argon particles revealed that large DNA alterations might be involved in these mutants.更多还原