柞蚕精子的动态观察及质量测定

Dynamic Observation and Quality Determination of Antheraea pernyi Sperm

柞蚕卵未受精率高是限制“二化一放”生产模式发展的主要问题,通过研究不同低温贮藏时间对柞蚕精子活动能力和受精能力的影响,比较6个二化性柞蚕品种和1个一化性柞蚕品种精子的耐低温贮藏能力,探索“二化一放”制种期柞蚕卵未受精率高的内在原因。分别在春季制种期和“二化一放”制种期对不同柞蚕品种的精子进行动态观察,并测试其活动能力和受精能力,结果表明:柞蚕精子存在有核精子和无核精子两种类型,其中有核精子活化前呈束状,不具有运动性,活化后分散打开,而无核精子具有运动性,能够快速向有核精子聚集,帮助其纠结成团状后向受精囊转移;“二化一放”制种期各二化性柞蚕品种精子的平均路径速度(velocity of awerage path,VAP)相较于春季制种期均显著下降,其中下降程度最小的品种是凤久和青黄1号,说明低温贮藏时间的延长对柞蚕精子的活动能力具有显著影响;“二化一放”制种期各二化性柞蚕品种精子的顶体酶活性相较于春季制种期均显著下降,其中下降程度最小的品种是凤久和青黄1号,说明低温贮藏时间的延长对柞蚕精子的受精能力具有显著影响;“二化一放”制种期柞蚕精子顶体酶活性与柞蚕卵未受精率之间呈显著线性关系,而精子的VAP与柞蚕卵未受精率之间无线性关系,说明在“二化一放”制种期通过顶体酶活性可以预测柞蚕卵未受精率;根据有核精子顶体酶的测定结果,6个二化性品种中以凤久的耐贮性最佳。上述结果可为柞蚕耐贮性研究与“二化一放”品种选育提供理论依据。

The high rate of unfertilized tussah eggs is the main problem limiting the development of“single rearing of bivoltine tussah”production mode.In this paper,the effects of different low-temperature storage time on sperm motility and fertilization ability of tussah were studied by comparing the low-temperature storage resistance of sperm of six bivoltine tussah varieties and one univoltine tussah variety,so as to explore the internal reasons of the high rate of unfertilized tussah eggs during the egg production period of“single rearing of bivoltine tussah”mode.The sperms of different tussah varieties were dynamically observed during the spring and the“single rearing of bivoltine tussah”egg production periods,and their motility and fertilization ability were measured.The results showed that there were two types of sperms in tussah:one was the eupyrene sperm,and the other was the apyrene sperm.The eupyrene sperms were bundle shaped with no motility before activation,but dispersed and opened after activation.The apyrene sperms had motility and could quickly aggregate to the eupyrene sperms to help them transfering to the spermathecae.The results showed that the velocity of average path(VAP)of sperms of every bivoltine tussah variety during the“single rearing of bivoltine tussah”egg production period decreased significantly compared with that in the spring period.The variety with the least decline rate were Fengjiu and Qinghuang 1,indicating that the extension of low-temperature storage period had a significant effect on the motility of tussah sperm.The sperm acrosin activity of each bivoltine tussah variety during the“single rearing of bivoltine tussah”egg production period decreased significantly compared with that in the spring period.The variety with the least decline rate were Fengjiu and Qinghuang 1,indicating that the extension of low-temperature storage time had a significant effect on the fertilization ability of tussah sperm.During the egg production period of“single rearing of bivoltine tussah”,there was a significant linear relationship between the tussah sperm acrosin activity and the rate of unfertilized tussah eggs.However,no linear relationship was observed between the VAP of sperm and the rate of unfertilized tussah eggs.The results indicate that the rate of unfertilized can be predicted by the acrosin activity.According to the determination results of acrosin of sperm,Fengjiu has the best storability among the six bivoltine tussah varieties.The research results can provide a theoretical basis for the study of storability and the breeding of“single rearing of bivoltine tussah”varieties.