|关键词: 酢浆草属 花粉形态 异型花柱 异常花粉 亲缘关系
|Analysis of Pollen Morphology and Phylogenetic Relationship among 14 Species of Oxalis
CHEN Shengyu, TANG Xiaoyun, XIAO Yun, HAN Ru, ZHAI Junwen, WU Shasha
College of Landscape Architecture and Art,Fujian Agriculture and Forestry University
|Most Oxalis are highly ornamentally valuable, but their taxonomy is difficult, which greatly limits the landscape application of this genus. The pollen morphology and exine ornamentation of 14 species of the Oxalis were observed using scanning electron microscopy, and their pollen morphology was clustered and analyzed to explore their interspecific relationship based on the results of palynological clustering. The results were as follows: (1) The pollens of the 14 species observed were subspheroidal or oblatesphere, and in polar view they were all 3-colpate, of which 96.3% were medium-sized and 3.7% were small, with different style types showing the largest grains are produced in stamens with long filaments and the smallest ones in stamens with short filaments; most pollen grains were 3-colpate, sparsely 2-colpate and 4-colpate, O. stellata and O. pes-caprae, respectively; exine ornamentation can be divided into two categories: supra-areolate and reticulate. (2) For the first time, three species with aberrant pollen grains were observed, namely O. glabra, O. simplex and O. pes-caprae. The aberrant pollens exhibit as abnormal number and arrangement of the colpi, but normal exine structure. There were 2-zonocolpate grains in O. glabra, spiralaperturate grains in O. simplex, and 4-zonocolpate grains and spiralaperturate grains in O. pes-caprae. (3) The 14 species can be divided into two categories according to the exine ornamentation, one includes O. massonorum and O. nidulans with supra-areolate pollen. The other category includes 12 species with reticulate pollen. Species in the latter category can be further divided into four types: O. glabra, O. versicolor, and O. tenuifolia are more closely related; O. compressa, O. pes-caprae, O. namaquana, and O. fabaefolia are more closely related; O. bowiei, O. stellata, and O. perdicaria are more closely related; O. zeekoevleyensis and O. simplex are relatively distantly related to other Oxalis. The pollen morphology is a valuable criteria to clarify their phylogenetic relationship, and facilitate selection of parents in Oxalis cross breeding.
|Key words: Oxalis Pollen morphology Heterostyly Aberrant pollen Phylogenetic Relationship