Abstract Detail

Evolutionary Developmental Biology (Evo-Devo)

Noroozi, Maryam [1], Cohen, Jim [1], Witherspoon, Jocelyn [2], Ryan, Gillian [1], Bogler, David [3], Miller, James [3], Riahi, Mehrshid [4], Ghahremaninejad, Farrokh  [4].

Pollen diversity and evolution in Boraginaceae.

Boraginaceae is one of the largest families of Lamiidae and has a cosmopolitan geographic distribution, being particularly well represented across the Mediterranean region, western North America, and central Asia. The family is characterized by many floral and nutlet features, such as scorpioid cymose inflorescence, gynobasic style, nutlet ornamentation, and attachment and pollen is quite diverse in the family.  Indeed, size, shape, number of apertures, exine ornamentation of pollen is variable across the family. The diversity of pollen characteristics in Boraginaceae is more substantial than that of many other families. Both qualitative and quantitative pollen morphological characters are significant for taxonomic identification of subfamily, tribes, and subtribes or even lower taxonomic levels such as genera. Despite all of this diversity, patterns of variation and evolution have not been comprehensively examined throughout Boraginaceae. Using both scanning electron microscopy imaging of the pollen grains and images from published literature, a set of seven palynological characters (three quantitative and four qualitative) was constructed from 556 species from nine tribes of the family. In addition, utilizing a molecular phylogeny based on 17 chloroplast DNA regions and ITS, ancestral state reconstruction, using Maximum parsimony and Maximum likelihood approaches, was conducted for five pollen-grain characters, including P and E-axis, P/E ratio, pollen shape, and aperture number, for 302 species of Boraginaceae. The results showed the pollen size in Boraginaceae varied from very small to medium. The greatest variation in pollen shape and outline was observed in Lithospermeae. The number of apertures showed more diversity within Boragineae and Lithospermeae with three to more than ten apertures however, all tribes of Cynoglossoideae revealed three. Furthermore, the ancestral character state reconstructions resolved small pollen, prolate, isoaperture and three aperture number as ancestral for the family. Of the all tribes, the greatest number of shifts in pollen size and aperture number were observed in Lithospermeae and Boragineae. Generally, pollen characteristics differ between Echiochiloideae, Boraginoideae, and Cynoglossoideae; also, there are differences between Trichodesmeae and the other tribes in Cynoglossoideae. Correspondences and correlation between palynological and molecular data in addition to patterns of character evolution are determined and suggestions made for future palynological and molecular investigations of Boraginaceae.

1 - Kettering University, 1700 University Ave., Flint, MI, 48504, USA
2 - Sacramento State University, CA, USA
3 - Missouri Botanical Garden, 4344 Shaw Blvd, St. Louis, MO, 63110, USA
4 - Kharazmi University, 43 Moffateh ave., Tehran, 15719-14911, Iran

Keywords:
ancestral state reconstruction
pollen shape
aperture
quantitative characters 
Maximum likelihood .

Presentation Type: Poster
Session: P, Evolutionary Developmental Biology (Evo-Devo) Posters
Location: Virtual/Virtual
Date: Tuesday, July 28th, 2020
Time: 5:00 PM Time and date to be determined
Number: PEV006
Abstract ID:622
Candidate for Awards:None