关键词: 土地利用, 土地利用, 生态风险, PCA模型, K-means评价模型, 长沙市

Abstract:

In order to discuss the effect of cultured time on parthenogenetic development of bovine oocytes in vitro, the study was designed on the basis of previous studies, by comparing the cleavage rate and blastocyst rate of three different groups of parthenogenetic embryos, so as to determine the existence of differences of parthenogenetic embryo developmental capability under different cultured time in vitro. The results showed that the cleavage rate was not significantly different among three groups under different cultured time in vitro, and the cleavage rate of oocytes under 22h cultured time in vitro was slightly higher than that of 18.5h and 25.5h. The blastocyst rate was significantly different among three groups, in which the group of oocytes under 22h cultured time in vitro was significantly higher than that of the other two groups. The results indicated that different cultured time in vitro did affect the development of parthenogenetic embryos differently. It would bring adverse effects on the development capability of parthenogenetic embryos if the cultured time was too long or too short.