以蔷薇科三个亚科九种植物的叶为材料， 利用傅里叶变换红外光谱法对九种植物进行亲缘关系分析和品种鉴定。 叶中主要含有大量的碳水化合物、 蛋白质、 脂类、 核酸等物质。 糖类物质的峰主要在1　440～775 cm-1之间， 1　440～1　337 cm-1为纤维素、 木质素的振动峰， 1　000～775 cm-1为核糖的伸缩振动。 蛋白质的峰主要在1　620～1　235 cm-1之间， 1　620　cm-1为蛋白质酰胺Ⅰ带的CO伸缩振动， 1　523 cm-1为蛋白质酰胺Ⅱ带N—H和C—N吸收峰。 脂类物质的峰主要出现在2　930～1　380 cm-1之间， 2　922　cm-1为脂肪CH2的伸缩振动， 1 732 cm-1是脂肪酸CO的伸缩振动。 核酸的标志峰出现在1 250～1 000 cm-1， 1　068 cm-1是磷酸基团的对称伸缩振动， 1　246 cm-1是磷酸基团的不对称伸缩振动。 研究结果表明： FTIR光谱数据经平滑、 标准化处理、 二阶求导、 主成分分析和系统聚类建立的聚类分析模型与传统分类结果相一致。 杏、 樱桃聚为一类（李亚科）， 翻白叶、 月季、 草莓聚为第二类（蔷薇亚科）， 火棘、　苹果、 枇杷、 海棠聚为第三类（苹果亚科）， 亚科聚类正确率为100%， 但属聚类的正确率仅为55.56%。 利用该聚类模型进行物种鉴定正确率为100%。 该项研究为植物的亲缘关系分析提供了新的思路与方法。

Leaves of nine kinds of plants from three subfamily of Rosaceae were used as materials. Genetic relationship was analyzed and species were identified through studying FTIR of nine kinds of plants. Leaves mainly contain large amounts of carbohydrates, proteins, lipids, nucleic acids and other substances. The peaks of carbohydrates are mainly between 1　440　and 775 cm-1. The vibration peaks of the cellulose and lignin are between 1　440 and 1　337 cm-1. The peaks between 1　000 and 775 cm-1 are stretching vibration of ribose. The vibration peaks of protein are between 1　620　and 1　235 cm-1. The peak at 1　620 cm-1 is sensitive to CO stretching vibration of protein amide　Ⅰ. The peak at 1　523 cm-1 is assigned to N—H and C—N stretching vibration of protein amide Ⅱ. Peaks of lipids mainly appeared between 2　930 and 1　380 cm-1. The peak at 2　922 cm-1 is CH2 stretching vibration of fat. The peak at 1　732 cm-1 is CO stretching vibration of fatty acids. The mark peak of the nucleic acid appears in the region between 1　250 and 1　000 cm-1. The peak at 1　068 cm-1 is due to the symmetric stretching vibration of PO2－ group of the phosphodiester-deoxyribose backbone, and the peak at 1　246　cm-1 is associated to the asymmetric stretch vibration of PO2－ group. The results showed that the cluster model is established by smoothing, standardizing, the second derivative, principal component analysis and Hierarchical cluster analysis. It is accordant with the traditional classification. The result of cluster shows that Prunus armeniaca L. and Prunus seudocerasus Lindl. were clustered into one (Prunoideae). Potentilla fulgens Wall. Rosa chinensis Jacd and Fragaria ananassa Duchesne var. were clustered into the second (Rosoideae). Pyracantha fortuneana Li, Malus pumila Mill. Eriobotrya bengalensis Hook.f.and Malus hallianna Koehne were clustered into the third (Pomoideae). The correct rate of cluster at subfamily is 100%. The correct rate of cluster at genus is 55.56%.　The correct rate of identification is 100% when unknown species waiting for determined were laid into the model of Hierarchical cluster to identify. This study provides a new thought and method for genetic relationship analysis of planst.