菌根真菌对^(60)Co-γ辐射后铁皮石斛种子萌发的影响

Effect of Mycorrhizal Fungi on the Germination of Dendrobium candidum Seeds After^(60)Co-γIrradiation

为了解^(60)Co-γ射线对铁皮石斛种子萌发和幼苗形成产生的辐射效应,以及胶膜菌属(Tulasnella)菌根真菌对辐射后铁皮石斛种子萌发的影响,本研究采用不同梯度剂量(20~120 Gy)^(60)Co-γ射线辐射处理铁皮石斛种子,对辐射种子分别进行非共生萌发[1/2MS、燕麦培养基(OMA)]、菌根真菌共生萌发(OMA接种菌株JL4、JL2)培养,比较分析非共生和共生培养方法对辐射种子萌发率和成苗率的影响,观察幼苗表型变化。结果表明,在非共生萌发(1/2MS)条件下,铁皮石斛种子半致死剂量为62 Gy,在与不同胶膜菌属菌株共生萌发后,半致死剂量为69 Gy(JL2)和63 Gy(JL4)。种子萌发率随辐射剂量的增高而降低,低剂量(20 Gy)处理加速了幼苗形成,高剂量处理(90、120 Gy)抑制了幼苗形成;培养115 d后,20 Gy处理成苗率较对照显著提高,分别达到18.26%(1/2MS)、15.00%(JL2)和17.86%(JL4);高剂量(90、120 Gy)处理种子在共生萌发条件下可获得表型变化更明显的幼苗,具体表现为幼苗高长、假鳞茎粗壮。本研究将种子辐射与兰科菌根真菌共生萌发相结合,为促进铁皮石斛辐射种子恢复、提高辐射诱变效率、高效创造铁皮石斛新种质提供了技术参考和科学依据。

To understand the effects of^(60)Co-γirradiation on seed germination and seedling formation of Dendrobium candidum,as well as the effect of orchid mycorrhizal fungi on the germination of irradiated seeds,D.candidum seeds were irradiated with^(60)Co-γrays at doses ranging from 20 to 120 Gy.The irradiated seeds were then treated with two methods:asymbiotic germination on 1/2 MS medium or OMA medium and symbiotic germination with Tulasnella sp.JL2 or JL4.The germination rates and seedling formation rates of irradiated seeds with two culture methods were compared and analyzed,and the phenotypic changes of seedlings were observed.The results showed that the semi-lethal dose of asymbiotically germinated seeds on 1/2 MS medium was 62 Gy,and the semi-lethal dose of symbiotically germinated seeds was 69 Gy(JL2)and 63 Gy(JL4),respectively.With increasing irradiation dose,seed germination rates were decreased.Low dose(20 Gy)treatment increased seedling formation rates,while high dose treatments inhibited seedling formation rates(90,120 Gy).After 115 days of growth,the seedling formation of seeds treated with 20 Gy ray was much improved than the 0 Gy control,reached up to 18.26%(1/2 MS),15.00%(JL2),and 17.86%(JL4),respectively.Seedlings germinated after high dose(90,120 Gy)treatments had more pronounced phenotypic changes during symbiotic germination,including taller seedlings and sturdier pseudobulb.We combined seed irradiation with orchid mycorrhizal fungi symbiotic germination in this study,which offers a technical reference and scientific foundation to promote the recovery of irradiated D.candidum seeds,improve the irradiation mutagenesis efficiency,and effectively produce new D.candidum germplasm.