Abstract
Abstract Lessingianthus plantaginoides (Vernonieae, Asteraceae) is a small natural tetraploid shrub that inhabits rocky highlands from South America. The population studied inhabits and covers an extensive region of a private reserve with high local biodiversity and animal and plant endemisms. With the purpose of providing insights into the cyto-embryology of this tetraploid species, the aims of this study were: to perform an ontogenetic study of the male and female gametophytes of L. plantaginoides; to carry out detailed meiotic analysis and evaluate the fertility of this species; to document and provide highlights on taxonomic implications of their reproductive aspects. Lessingianthus plantaginoides presented the following male and female gametophyte traits: dicotyledonous type of anther wall development, tetrahedral tetrads, 3-celled mature pollen grains; development of the chalazal megaspore, monosporic embryo sac and Polygonum type of megagametophyte development. The meiotic behavior was regular, the spores were tetrads of equal size and the pollen grains were highly stainable. Lessingianthus plantaginoides is a highly diplodized autotetraploid that reproduces sexually and has high meiotic regularity; which is apparently responsible for its colonization potential. It now seems certain that polyploid speciation plays a significant role in the establishment and diversification of the genus.
Highlights
IntroductionPolyploidy, defined as the duplication of the genomic complement, is a form of plant speciation
Polyploidy, defined as the duplication of the genomic complement, is a form of plant speciation. It was formerly ignored as a dead end, until phylogenetic analyses revealed the contribution of polyploidy to the evolutionary history of the Angiosperms (Soltis et al 2003)
For all the above mentioned and taking into account the extensive distribution of this species around the hills, and its high relative abundance that covered an extensive part of the region reaching up a height of 179 masl., and considering the absence of cyto-embryological data, the aims of this study were: (a) to perform an ontogenetic study of the male and female gametophytes of L. plantaginoides, (b) to carry out detailed meiotic analysis and evaluate the stainability of pollen grain, (c) to document and provide highlights on taxonomic implications of their reproductive aspects
Summary
Polyploidy, defined as the duplication of the genomic complement, is a form of plant speciation. The research was primarily focused on the origin and maintenance of polyploids (Abbott & Lowe 2004; Schinkel et al 2017; Certner et al 2017; Kovalsky et al 2017), the frequency of recurrent polyploidization (Soltis & Soltis 1999; Soltis & Soltis 2000; Falistocco 2016), the ecological effects of plant polyploidy (Ramsey 2011; Beest et al 2012), and the genetic, epigenetic, chromosomal, and genomic consequences of polyploidization (Comai 2005; Adams & Wendel 2005; Rapp & Wendel 2005; Paterson et al 2006; Sémon & Wolfe 2007; Leitch & Leitch 2008; Tang et al 2008; Anssour et al 2009; Hardion et al 2015) These topics are being updated in different plant families. Despite being an important phenomenon in the origin and diversification of composites and considering the great amount of species, there are very few studies concerning the implications and scopes of polyploidy in the different tribes
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