This study were carried out to investigate the effective concentration of cryoprotective agents and sucrose by one-step straw method, and to determine the optimum thawing temperature and equilibration time of frozen porcine embryos. The porcine embryos foflowing dehydration by cryoprotective agents and a various concentration of sucrose were directly plunged into liquid nitrogen and thawed in 3 water. Survival rate was defined by FDA test. The results are sunnnarized as follows : 1. The survival rates of porcine embryos after ultrarapid frozen4hawing in the freezing medium with a various concentration of glycerol, DMSO and propanediol added 0.25M sucrose were higher survival rate than those of sucrose concentration of 0.50M. 2. The survival rates of porcine embryos after ultrarapid ftozen4hawing in the freezing medium added 0.25M and 0.SOM sucrose were higher survival rate than those of sucrose concentration of 0.75M and 1.00M. 3. The temperature thawed at 2 and 3 resulted in a significantly higher embryos survival rate after 72 hrs in culture than did at 35. 4. The equilibration time on the survival rate of porcine embryos was attained after short period of time(2.5~5 min.) in the freezing medium higher than long period of time(10~20 min.).

The objective of this experiment was to study some possibilities to simplify freezing, thawing and transfer procedure of one-step straw method comparing with the conventional methods using bovine embryos. The previous work are also designed to investigate the thawing effect by development stage and its quality using the embryos. Results obtained were summarized as follows: 1. A total of 87 embryos from 14 donor cows were frozen-thawed and an average of frozen embryo/donor was 6.2. 2. The survival rates of morula stage(65.4%) were higher than those of blastocyst stage(57.l%) and vice versa in rate of morphological recovery (80% vs 95.4%). However. no significant difference was denoted between them. 3. In difference between the groups of good quality and poor quality. good quality was resulted in a significantly higher embryo survival rate(75%) and recovery rates(95%) than poor quality(P<0.0l). 4. In effects of non-permeable sugar dilution in added to l.0M glycerol. higher survival rates were orderd in sucrose. lactose, raffinose and xylose. But lactose-raffinose, sucrose-trehalose and xylose in added to 2.OM glycerol. 5. The highest survival rates were obtained by direct plunge into the liquid nitrogen with 3.OM concentration both of glycerol and trehalose. 6. The survival rates in vitro condition of one-step and direct plunge methods(75%-87.5%) were significantly higher than those of multiple steps (21.4-52.6%) in in vitro (P<0.0l). However, the results of single-step were critical in comparing to other steps of final pregnant conformation.

토양수분함량과 큰검정풍뎅이의 밀도 변화와의 관계를 파악하는데 필요한 기초 자료를 얻기 위해 토양수분함량이 큰 검정풍뎅이의 난과 유충의 생존에 미치는 영향을 조사하였다. 사양토와 식양토의 수분함량 15%와 25%에서는 난과 1, 2, 3령 유충 모두 79% 이상의 생존율을 보였으나 5%와 35%에서는 현저히 떨어졌다. 이 극한 수분함량에서는 토성에 따라 난과 유충의 생존율에 차이가 있는 것으로 보였다. 큰검정풍뎅이의 난은 생존할 수 있는 낮은 수분함량의 한계에 가까워질수록 발육기간이 길어졌다. 식양토에서 33-36%의 높은 수분함량에 난을 일정 기간 처리했을 때 배자 발육을 진행된 난일수록 잘 견뎠고 처리기간이 길어짐에 따라서 전란기간이 길어졌다. 또한 높은 토양수분함량에서는 3령 유충의 섭식 활동이 뚜렷이 억제되었다.

The purpose of this study is to clarify the relation of survival rates of seedling plants under grown orchardgrass populations and control by the difference cutting frequency. The orchardgrass populations investigated in this study have passed for 10 year

The effects of cryoprotectants (glycerol, DMSO and ethylene glycol) and the concentrations (0, 0, 25, 0.5and 1.0 M) of sucrose in the diluent on the is vitro survival of mouse morulae froaen rapidly in liquid nitrogenvapour were examined. When the embryos were equilibrated in 1.5 M cryoprotectants +0.25 M sucrose in one-step or in 3.0 M cryoprotectants +0.25 sucrose in two-step and diluted with 0, 0.25, 0.5, or 1.0 M sucrose solution after thawing, high survival rates were obtained in ethylene glycol (48.0% to 88.2 %) or in glycerol (35.0 % to 77.8 %). These results show that 1.5 M ethylene glycol is a highly efficient cryoprotective agent for the rapid freezing of mouse morula embryos and 0.5 M sucrose was optimal concentration in the diluent after thawing.

This study was conducted to investigate the effect of unilateral ovariectomy on the embryo survival and changes of plasma progesterone and estradiol concentration. Mature Angora rabbits were divided into 2 groups (Superovulation and unilateral ovariectomy after superovulation). Unilateral ovariectomied rabilts were subdivided into two groups according to the time of ovariectomy (24 hours and 96 hours after mating). The results obtained were summarized as follows; 1. After unilateral ovariectomy, survival rate and collecting rate of embryos recovered from contralateral and ipsilateral oviduct and uterus were not different, and were lower than intact rabbits. 2. Plasma progesterone concentration at 93, 99, 102 and 114 hours after HCG injection in superovulated rabbits were 12.9 0.5, 34.8 5.1, 12.2 2.7 and 43.4 5.8ng/ml, respectively. Mean progesterone concentrations were significantly higher at 99 and 114 hours than at 93 and 102 hours (p <0.05). But plasma estradiol concentration was not different. 3. Plasma progesterone concentration in unilateral ovariectomized rabbits was somewhat decreased after unilateral ovariectomy. Plasma estradiol concentration was not different.