Embryology of Hemerocallis L. and its systematic significance

• Published in: Plant systematics and evolution Vol. 303; no. 5; pp. 663 - 673
• Main Authors: Yan, Dan, Wang, Li-Juan, Zhao, Chun-Hai, Zhao, Yun-Yun, Liu, Jia-Xi
• Format: Journal Article
• Language: English
• Published: Vienna Springer-Verlag GmbH 01.05.2017; Springer Vienna; Springer Nature B.V
• Subjects: Aniline; Aquatic plants; Biomedical and Life Sciences; Cytokinesis; Embryogenesis; Embryology; Embryonic growth stage; Embryos; Endosperm; Hemerocallis; Integument; Life Sciences; Original Article; Ovules; Paraffin; Paraffins; Plant Anatomy/Development; Plant Ecology; Plant Sciences; Plant Systematics/Taxonomy/Biogeography; Pollen; Sectioning; Tetrads; Asparagales; Embryology; Liliales; Asphodelaceae; Systematic
• ISSN: 0378-2697; 1615-6110; 2199-6881
• DOI: 10.1007/s00606-017-1398-7

The embryology of the genus Hemerocallis L. was studied to re-evaluate its current systematic position proposed by recent phylogenies based on molecular data. Using the improved carbol fuchsin–aniline blue staining method and conventional paraffin sectioning technique, we followed the development of anther and pollen grain, ovule and female gametophyte, and embryo and endosperm up to seed maturity. Our results showed that the (1) anther wall development is of the Monocot type, with a one cell-thick middle layer and a secretory tapetum, (2) microsporocytes cytokinesis is of the intermediate type, (3) microspore tetrads are tetragonal or decussate, (4) pollen grains are two-celled, (5) ovary is superior and trilocular, with axile placentas bearing two collateral ovules per locule, (6) ovules are anatropous, tenuinucellate, and bitegmic, with micropyle formed by the inner integument, (7) megaspore tetrads are linear, and only the chalazal one is functional, (8) embryo sac development is typically of Polygonum type, (9) embryogenesis is of Graminad type, and (10) endosperm development is of nuclear type. Overall, our study thus confirms that the embryological features of Hemerocallis support its exclusion from Liliaceae in Liliales, its inclusion in Asparagales, and its affinities with Asphodelaceae.