Morphological and Chromosomal Features of Guizhou Wangmo Babu Tea.

Résumé

The taxonomic classification of Babu tea (Family Theaceae) was preliminarily investigated by analyzing its epigenetic morphology and chromosomal features. Morphological observations of three Babu Tea phenotypes (red flower/purple bud, pink flower/purple bud, and white flower/green bud) revealed that the stomata were located exclusively on the lower epidermis, and the anticlinal walls of epidermal cells were deeply undulated. The stomatal apparatus also consisted of two crescent-shaped guard cells, forming a spindle shape with thickened "T-shaped" ends. Furthermore, the outer stomatal arches had smooth surfaces, while the inner ones were shallowly undulated. Finally, subsidiary cells were covered by a shallowly undulated epidermal stratum corneum that was composed of three layers. Their pollen grains exhibited a prolate spherical shape. Based on pollen morphology, the Babu Tea was therefore classified within Sect. Theopsis Coh. St., Camellia. Chromosome counting and karyotype analysis further confirmed that the three phenotypes share a chromosome count of 2n = 2x = 30, with their karyotypes classified as Type 2A. These findings suggest that the three phenotypes share a common evolutionary origin.