DON抑制小麦种胚细胞周期启动的研究

Inhibition Effect of DON on Cell Cycle Activation in Wheat Embryo Cells

小麦种子在 0 .5～ 4.0 mg/L的脱氧雪腐镰刀菌烯醇 ( DON)溶液中萌发 ,用流式细胞仪检测胚细胞的周期时相并观察黄化苗的生长 .结果表明 ,对照组胚细胞在萌发 1 2 h开始启动细胞周期 ,此后 S期细胞比率迅速增加并在 2 0 h达到最大值 ,较萌发 1 0 h的 6.5%增加1 .78倍 ,约 1 4%的胚细胞在萌发的 2 2～ 2 6h间完成第一次分裂 ;DON抑制 G1期胚细胞的启动 ,小麦胚中 S期细胞比率随 DON浓度增加呈指数下降 ,3.5与 2 .0 mg/L的 DON可分别将小麦胚细胞阻滞在 G1期和 S期 ;小麦黄化苗的苗高与主胚根长均随 DON浓度升高呈线性下降 ,但 DON刺激小麦初生根数目增加 ,刺激作用以 1 .5mg/L最强 .以上结果说明DON因阻止了胚细胞周期的启动而抑制小麦种子萌发 .

The activation of the cell cycle in embryo cells of wheat ( Triticum aestivum L., cv. Lu Mai No. 22) seeds imbibing in 0.5～4.0 mg/L deoxynivalenol (DON) was studied by flow cytometric analyses. The results indicated that the majority of the embryo cells in wheat seeds were arrested at the G 1 phase of the cell cycle. The cell cycle was activated after the seeds imbibing in distilled water for 12 h, and then the relative percentage of S phase cells in wheat embryos were observed to increase steadily until a peak was reached on the 20 h imbibition. The number of S phase cells in wheat embryos imbibing in water for 20 h was 1.78 fold more than that imbibing for 10 h. When imbibing for 22 to 26 h, about 14% embryo cells in wheat seeds had finished their mitosis. The entry of the embryo cells at G 1 phase into S phase was strongly inhibited by imbibing the seeds in DON solution. The percentage of wheat embryo cells at S phase decreased exponentially with increasing concentration of DON treatment up to 4.0 mg/L. Embryo cells in wheat seeds could be blocked completely at G 1 phase and S phase by 3.5 and 2.0 mg/L DON treatment respectively. The seedling height and radicle length decreased linearly with increasing concentration of DON, while root number of etiolated wheat seedlings was accelerated by DON with a maximal stimulation concentration of 1.5 mg/L. These data suggest that the inhibition of wheat germination by DON results in inhibition of cell cycle activation in embryo cells.