【摘要】 用红宝石激光微束(聚焦光斑直径10μ)照射黑眶蟾蜍二、四、八细胞期的分裂球和原肠胚,产生的畸形胚胎和死亡率,可因发育时期不同和照射能量密度的大小有所差异。发育时期愈早,其死亡率愈高。在二细胞期,当照射能量密度低于312μJ/μm~2时,观察不出有显著的外部变化。照射能量密度提高到312、470或623μJ/μm~2时,胚胎死亡率亦随之增高;但用1244μJ/μm~2的能量密度的光束照射,全部胚胎死亡。正在分裂的卵被照射后,发育成为各样的畸形胚胎或蝌蚪而死亡,只少数能够发育至变态成小蟾蜍。用623μJ/μm~2能量密度照射二细胞期卵裂沟的卵,多数只能发育至原肠胚,少数发育成为头部分化不全的蝌蚪而死亡。用相同能量密度照射黑眶蟾蜍和泽蛙的二细胞期分裂球,由于黑眶蟾蜍卵皮层的色素较泽蛙的黑,增强了激光微束照射的效应,致使死亡率明显地提高。更多还原

【Abstract】 Blastomeres of the two,four and eight cell stage as well as embryos of the gastrula stage of Bufo melanostictus were irradiated with ruby laser microbeam of focusing diameter 10μ,and pulse duration lusec. After irradiation,a damage spot or a mushroom-like swelling would appear on the surface of the egg. It was found that the mortality of the embryos was closely related to energy densities of the laser microbeam used,and also the earlier tne stage of embryonic development was irradiated,the higher the mortality. In the two cell stage,when the energy density was below 312 μJ/μm~2,no conspicuous external change was observed. The mortality of the embryos increased as the energy density was raised from 312 μJ/μm~2 to 623 μJ/μm~2. However,all the embryos died early when the energy density was raised to 1244μJ/μm~2. Various abnormalities appeared on the embryos. or tadpoles,such as,a white patch lacking ectoderm on the body wall,curved tail, a small undeveloped head,smaller tadpoles with abdominal edema and shorter intestine etc. The majority of the enbryos which had been irradiated died in between the tail-bud stage and the closure of the operculum,and only a few embryos could develope to metamorphosis. When the cleavage furrow of the two cell stage was irradiated with an energy density of 623μJ/μm~2 most of the embryos died in the gastrula stage. When the blastomeres of the two cell stage of Bufo melanostictus and Rana limnocharis were irradiated with the same energy density and compared,the mortality of tne embryos of the former species was much higher than that of the latter. Since the eggs of Bufo melanostictus are much darker than those of Rana limnocharis,it is evident that the dark pigmented cortex of ihe eggs of Bufo melanostictus can enhance the effect of the laser microbeam.更多还原