中文摘要：

为给北京市昌平区流村镇沙果、冷海棠、暖海棠这3种近濒危乡土果树资源的保护与合理开发提供参考,笔者对这3种果树的种质状况、果实品质、濒危现状、栽培方式与管护水平等方面进行了全面调查与测定。调查测定结果表明,不同单株沙果果品的可溶性固形物、单果重、果肉肉质差异较大,可溶性固形物变幅为10.81%~15.13%,单果重变幅为22.3~40.27 g,果皮分为中厚稍脆和中厚稍韧2种,肉质细,多汁;暖海棠、冷海棠果实的各项实测指标则差异不大,果品品质较一致。其中,暖海棠可溶性固形物变幅为17.00%~18.21%,单果重变幅为8.25~10.66 g,果肉细脆紧实;冷海棠可溶性固形物变幅为14.23%~16.55%,单果重变幅为6.47~9.03 g,果肉细脆。根据以上情况,可初步推测,沙果各单株间可能存在较大变异,极有可能从中筛选出优良的品系。3种小苹果果实糖酸比均处于口感的适度范围,是开发鲜食品种良好的育种材料。针对目前的现状,笔者从古树认定、加强管理、开发文化内涵、加强科学研究等方面提出了该镇小苹果古树保护与发展的建议。

英文摘要：

Abatract： In order to protect and offer reference of rational exploitation for three kinds of endangered nativecrab-apple（Malus asiatica, Malus prunifolia and Malus micaromalus） in Liucun town in Changping district,the author investigated measured germplasm, fruit quality, endangered status, cultivation mode and the level ofmanagement and protection and so on. The results showed that great differences existed in the content ofsoluble solid, weigh of single fruit and pulp quality, soluble solid changed with rate of 10.81%-15.13%, weighof single fruit changed from 22.3 g to 40.27 g. Pericarp can be divided into mid-thick crisp and mid-thicktough, pulp quality was fine and succulency. The actual measurement index of two crab-apple species（Malus prunifolia and Malus micaromalus） had no differences in fruit quality. The content of soluble solid and weigh ofsingle fruit of Malus micaromalus changed with rate of 17.00%-18.21% and 8.25-10.66 g, pulp thin crisp andtight. The content of soluble solid and weigh of single fruit of Malus prunifolia changed with rate of 14.23%-16.55% and 6.47-9.03 g, pulp thin and crisp. Based on the result, the author inferred that there might beconsiderable variation among individual trees and it was possible to screen out excellent strains. The sugar acidratio was in the moderate range of taste, which means all of them were good breeding material to develop fresh varieties. In view of the present situation, the author proposed protective and developmental suggestions fromaspects of ancient tree affirmation, strengthen management, cultural connotations development, strengthenscientific research and so on.