60Co-γ和电子束辐照对紫薇种子萌发及幼苗生长的影响

Effects of 60Co-γand Electron Beam Irradiation on the Germination and Seedling Growth of Lagerstroemia indica

使用不同剂量的60Co-γ和电子束辐照紫薇(Lagerstroemia indica)干种子,观察种子萌发和幼苗的生长情况,以确定适合紫薇的辐照类型和剂量。结果表明:在辐照剂量范围内2种辐照的种子发芽率均出现先促进后抑制的现象,成苗率随辐照剂量增加显著降低;60Co-γ辐照对幼苗株高有先抑制后促进的现象,电子束辐照对幼苗株高有抑制现象;2种辐照对幼苗分枝长和分枝数均有明显抑制作用,随辐照剂量增加显著降低;60Co-γ辐照对幼苗地径有一定程度的抑制作用,电子束辐照产生的变异较大;2种辐照对幼苗生长的综合分析显示在相同剂量条件下(250 Gy),电子束辐照处理下的紫薇幼苗分枝更长,地径更高;电子束辐照对紫薇幼苗分枝长和地径产生的变异更大。根据成苗率估算,紫薇干种子60Co-γ适宜辐照剂量为113.06~299.63 Gy,电子束适宜辐照剂量为245.5~372.24 Gy,紫薇对60Co-γ辐照的敏感度更大。本研究结果可为紫薇辐照育种提供依据,促进紫薇育种进程。

Radiation mutagenesis is an important method for plant breeding,which can improve the mutation rate and shorten the breeding time.Plants are differently sensitive to irradiation,and adequate irradiation dose could increase mutation frequency and breeding efficiency.Seeds of Lagerstroemia indica were treated with 60Co-γand electron beam at different doses to observe their germination and seedling growth to find the best irradiation source and dose..The results showed that the germination rates of the seeds treated with both 60Co-γand the electron beam were first promoted and then inhibited,and that the seedling survival rate decreased significantly with the irradiation dose.The 60Co-γirradiation was found to inhibit and then promote the plant height,while the electron beam irradiation inhibited the plant height.Both 60Co-γand the electron beam had significant inhibition effects on the branch length and branch number of the seedlings.The 60Co-γirradiation had little inhibition effect on the ground diameter of the seedlings,while the electron beam irradiation had highly different effect on the ground diameter.Comprehensive analysis of the seedling growth under the two sources of irradiation showed that the seedlings of L.indica treated with the electron beam at the same dose of irradiation to the 60Co-γirradiation had longer branches and higher ground diameter and varied greatly in branch length and ground diameter.When calculated at the seedling survival rate of L.indica treated,the optimum irradiation dosage was 113.06 Gy to 299.63 Gy for 60Co-γ,and 245.5 Gy to 372.24 Gy for electron beam.L.indica was more sensitive to 60Co-γirradiation.These results would provide a theoretical basis for mutation breeding and acceleration of the breeding process of L.indica.