极低温辐照大麦种子及热冲击后处理诱变效应的研究

MUTAGENIC EFFECTS OF GAMMA-RADIATION AT EXTREMELY LOW TEMPERATURE AND HEAT SHOCK POST TREATMENT ON BARLEY

本试验研究了极低温(-196℃)条件下γ射线辐照大麦干种子和极低温辐照结合热冲击后处理的诱变效应。结果表明:1.与常温条件下辐照相比,极低温条件下辐照及结合热击冲后处理均能显著减轻大麦M_1代的生理损伤和染色体畸变率,其半致死照射量分别提高13kR和30kR;2.M_2代的突变率随照射量升高而增加(r=0.9922^(··)),而与不同温度条件没有关系;3.在极低温条件下用50kR辐照及用60—65kR辐照结合热冲击后处理,与常温条件下用35—40kR辐照相比,没有加重M_1代的辐射损伤,而M_2代的突变率则显著增加,其诱变效率分别平均提高30％和48％。

The mutagenic effects of gamma-rays irradiation on dry seeds of barley at extremely low temperature (-196℃) and at-196℃ followed by heat shock (60℃) post-treatment were studied in this experiment.The results indicated.,(1) Compared with irradiation at room temperature,irradiation at-196℃ and at-196℃ followed by heat shock post-treatment could significantly decrease radiation induced physiological damages and chromosomal aberrations in the M1 generation and their average D60 values were increased by 13 kR and 30 kR respectively.(2)The frequencies of mutants in the M2 generation were positvely related with irradiation doses (r=0.9922) and not related with the different temperature.(3)Compared with irradiation with 35-40 kR at room temperature,irradiation with 50 kR at-196℃ and irradiation with 60-65 kR at-196℃ followed by heat shock post-treatment did not add the M1 damages but significantly raised the frequencies of M2 mutants and increased the mutagenic efficiencies by 30% and 48% respectively.