<正>根据国土资源管理信息系统中对数据并行编辑和时空数据管理需要，提出了基于ESRI的SDE和 ArcObj ects系统的宗地版本管理和历史回溯的设计方案，利用VB和ArcObj ects编程实现宗地版本管理和历史回溯，并应用于广西梧州市国土资源管理信息系统中，取得了理想的效果。

Researches had been carried out on cryopreservation of pollen from Changbai Mountain and Daxinanling Mountain. The results indicated that desiccation duration affected the pollen germination after cryopreservation. The germination viability of pollen that was prefrozen for 12h was higher than that of 8h, 24h. Treatment at varied temperate of 0℃ (8h)→-10℃ (8h)→-20℃ (8h) could greatly increase the viability of pollen stored in liquid nitrogen before being thrown into liquid nitrogen. The defreezing method of -20℃ (8h)→4℃ (8h)→25℃ (8h) was better than other two treatments.