Abstract:

Armeniaca hongpingensis T. T. Yu & C. L. Li is a critically endangered species distributed only in Hongping Town, Shennongjia, Hubei Province, China. According to the Flora of China, A. hongpingensis and A. mume var. bungo Makino may be natural hybrids of A. mume Lam. and A. vulgaris Siebold. To date, however, no morphological study on the relationship between A. hongpingensis, A. vulgaris, A. mume, and A. mume var. bungo has been conducted. Through field investigations, 21 quantitative and 15 qualitative leaf, flower, fruit, kernel, and branch characters were obtained, followed by cluster analysis. Results showed that both PAM and UPGMA cluster analysis clearly divided the specimens into four species, indicating obvious distinguishing characters among them. Based on principal component analysis, the absolute weight values of annual branch color and hair-covering status, hair-covering status of leaf and fruit, leaf shape index (leaf shape, leaf tip, leaf base), and surface characters of kernel in the first three principal components were all above 0.9, indicating that these traits play important roles in the classification of the four Armeniaca species. Based on electron microscopy, the pollen grains were identified as single grain (monads), isopolar, radially symmetrical, and tri-colporate. The pollen surfaces of A. vulgaris, A. mume, and A. mume var. bungo were striate-ornamented, while the pollen of A. hongpingensis was discontinuously striped and showed inconspicuous perforation. The epidermal cells of the leaves of the four plants all showed striate keratinization. Compared to the other species, the stripes on the cell surface of A. hongpingensis were often curved, overlapped, and without fixed direction. According to cluster analysis and micromorphological characters, A. hongpingensis should be treated as an independent species from A. vulgaris and A. mume.

摘要：

本研究通过野外调查获得洪平杏（Armeniaca hongpingensis T. T. Yu & C. L. Li）、杏（A. vulgaris Lam.）、梅（A. mume Siebold）和杏梅（ A. mume var. bungo Makino）有关的叶、花、果、果核及枝条的21个定量性状和15个定性性状，并对这些数据进行了聚类分析。结果显示，无论是PAM聚类还是UPGMA聚类分析都可清晰地将4种杏属植物分开，说明物种之间具有明显的区分特征。主成分分析的前3个主成分中，一年生枝颜色、被毛情况，叶及果实被毛，叶形指标（叶形、叶尖、叶基）和果核表面特征的绝对权重值都在0.9以上，表明这些性状在4种杏属植物的分类中具有重要的作用。电镜扫描观察结果发现，供试花粉均是单粒花粉，等极，辐射对称，具3孔萌发沟。杏、梅、杏梅的花粉表面纹饰均为条纹状，但洪平杏的表面纹饰为间断条纹，且有不明显穿孔。4种植物叶上表皮细胞均具条纹状角质增厚。与其他种相比，洪平杏细胞表面条纹常弯曲、交叠，无固定走向。根据聚类分析结果和微形态特征，支持将洪平杏作为区别于梅和杏的一个独立种的处理。