Abstract: To investigate the effects of ⁶⁰Co-γ radiation on seed germination and seedling growth of Muhlenbergia capillaris (Lam.) Trin.,dry seeds of Muhlenbergia capillaris were exposed to different doses of ⁶⁰Co-γ radiation (100,200,300,400 and 500 Gy). Responses of the seed germination rate,germination percentage and germination index,plumule and radicle length,plant height,root length,root diameter,root volume and average root length of M. capillaris seedlings to different doses of ⁶⁰Co-γ radiation were analyzed. With the increase of radiation dose,the germination rate,germination potential and germination index all showed a single-peak curve,and reached maximum values at 400 Gy. Low dose radiation (100 Gy) increased the length of plumule,while the length of radicle decreased with the increase of radiation dose. Compared to the non-radiation control,the five radiation treatments lowered plant height,root length,leaf width,number of leaves and number of green leaves of the seedlings. With the increase of radiation dose,the total length and surface area of root first increased and then decreased,while the total volume of root showed a continuously decrease trend,and the average diameter of root was not significantly affected by the radiation treatment except at dose of 400 Gy. Based on the death rate under different ⁶⁰Co-γ radiation doses,the semi-lethal dose of ⁶⁰Co-γ radiation for Muhlenbergia capillaris dry seed was predicted at approximately 274 Gy. The results obtained in the present study would provide a theoretical basis and technical support for the radiation mutation breeding for Muhlenbergia capillaris.

Key words: Muhlenbergia capillaris, ⁶⁰Co-γ radiation, Seed germination, Seedling growth

摘要： 为阐明⁶⁰Co-γ射线辐射对粉黛乱子草种子萌发及幼苗生长的影响，本研究采用⁶⁰Co-γ射线不同辐照剂量(100，200，300，400，500Gy)对粉黛乱子草种子进行辐射处理(以无辐照处理为对照)，分析粉黛乱子草种子萌发及幼苗生长相关指标对不同辐射处理的响应。结果表明，随着辐射剂量的提高，发芽率、发芽势和发芽指数都呈现先上升后下降的趋势；低剂量辐射提高了胚芽长度，而胚根长度则随着辐射剂量的提高呈逐渐降低的趋势。经辐射处理的幼苗株高、根长、叶宽、叶片数及绿叶数均低于对照。随着辐射剂量升高，根系的总长和表面积呈现先增加后降低的趋势，而根系总体积呈逐渐降低趋势，根系平均直径受辐射剂量影响较小。线性回归分析结果表明，粉黛乱子草干种子⁶⁰Co-γ射线的半致死剂量约为274Gy。本研究可为粉黛乱子草辐射诱变育种研究提供参考。

关键词: 粉黛乱子草, ⁶⁰Co-γ射线, 种子萌发, 幼苗生长