辐照稻谷种子的种胚微观结构特性及其萌发特性研究

Effect of γ-Ray Irradiation Pre-treatment on Embryo Structure and Germination Characteristics of Rice Seeds

稻谷种子采用0—10kGγ的γ射线进行辐照处理后，立即对其胚结构进行显微观察，结果发现，不同剂量辐照稻谷种子的胚芽和胚根的微观结构都不同程度地受到了射线的影响，胚根与胚芽的外形和轮廓随着辐照剂量的增加逐渐模糊。这是由于γ射线对胚根和胚芽的组织细胞的破坏作用导致的，并且γ射线对胚根的影响要明显大于对胚芽的影响。对辐照稻谷种子立即做的萌发实验也进一步证实了微观结构观察的结果，实验表明，受γ射线辐照后，稻谷种子在萌发过程中发出的芽变短，而根几乎消失，根据对种子发芽率的定义，此时稻谷种子的发芽率几乎为0。进一步对辐照稻谷种子经过长期贮藏后再进行萌发实验表明，不同剂量辐照稻谷种子经过2年左右的贮藏，其发芽率有不同程度的提高，有些甚至提高到一个相当高的水平，且发芽率恢复的最高程度随辐照剂量的变化有所不同。此外，辐照稻谷种子在贮藏过程中的发芽速率也不同。这是由于辐照种子在贮藏过程中的自我修复作用与呼吸作用的共同作用的结果。

Rice was irradiated with dose up to 10 kGy after harvest. It is showed from microscopic observation that the embryonal structure of rice （Oryza sativa L. ）, including structure of embryo bud and radicle, is affected by the γ- ray irradiation; the outline and venations of the irradiated embryo and radicle gradually blur with increasing irradiation dose. These changes are due to the breakage of embryo cells. It can also be seen that the influence of γ- ray irradiation on the structure of radicle is heavier than that on embryo bud. The results of microscopic observation are confirmed by a germination experiment, showing that the lengths of buds of irradiated rice are diminished, the roots of irradiated rice disappear, and the germination rate of irradiated rice is 0 %. The changes of germination of the irradiated rice after storage are shown. After long - term storage, the germination rate of the irradiated rice increases from 0 %, and some irradiated rice samples even give comparatively high values of germination rate within two year＇ s storage. These changes may due to the selfrepair of irradiated rice. The effects of store time on germination characteristics of non - irradiated and irradiated rice samples were also studied.