Assessment of the modes of pollen dispersal of Vernonia amygdalina Del. and Vernonia calvoana Hook

Abstract

The study of pollen dispersal and mode of fertilization of Vernonia amygdalina and Vernonia calvoana is a prerequisite to the understanding of genetic diversity and elaboration of improvement programs for the Vernonia genus. In this study, precise experimental designs were made for morphological and biological observations on Vernonia species capitulum in order to assess the distinctive effects of each of the three possible pollen transportation agents (insects, wind and rain water) on pollination. Results obtained show that the exclusive mode of pollen dispersal is entomophilous. Even though allogamy and autogamy are observed as two possible modes of fertilization in Vernonia spp., some arguments tend to favour allogamy. However, there is no clear cut position on the issue, hence the need for confirmation by further experimentation in controlled pollination. This study paves the way for the establishment of a genetic improvement program for this genus based on the results on pollen dispersal.

Secondary metabolite contents and antimicrobial activity of leaf extracts reveal genetic variability of Vernonia amygdalina and Vernonia calvoana morphotypes

“…In this order, the morphotypes could be successively classified as VCAB, VCAV, VAA, VALF, VCSB, and VCSV. This ranking corresponds exactly to the classification established [15] on the same morphotypes for the taste of the leaves (from the most bitter to the least). The tannin and flavonoid contents could thus constitute evaluation parameters for plant leaf taste.…”

“…Nguimkeng et al. [15] identified six different genotypes grown by local indigenes of Cameroon and noted variability within the genus. However, it is important to investigate the chemotaxonomic aspects of this genus in order to improve knowledge on the identification and diversity of its chemical contents.…”

“…The existence of wide genetic variability in the genus Vernonia was established by Nguimkeng et al. [15] through the study of its pollen. However, to the best of our knowledge, no such study has been undertaken on the genetic variability of Vernonia concerning its secondary metabolites, hence the need for phytochemical analysis of some secondary metabolites among the species (genotypes) of V. calvoana and V. amygdalina to highlight intraspecific variations.…”

Genetic diversity and population structure of Vernonia amygdalina Del. in Uganda based on genome wide markers

“…The near-zero F is estimate based on geographically determined populations signifies the presence of random mating also known as Hardy–Weinberg equilibrium, and that the available parents experience a high level of outcrossing leading to homogenization of the populations. Concerning the mode of fertilization, the flower of Vernonia is considered to exhibits protandry, which imposes allogamy on this plant [ 19 ].This also implies that the mode of dispersal between the two populations is quite efficient.…”

“…It has dark green leaves and a rough bark, with height of up to 10 m. Its flowers are bisexual, regular, numerous, and strongly exserted ( https://uses.plantnet-project.org/en/ Vernonia amygdalina (PROTA)). The flower of Vernonia is considered to exhibit protandry, which imposes allogamy on this plant [ 19 ]. Vernonia amygdalina leaves, bark and roots are harvested for treatment of amoebic dysentery, gastrointestinal disorders, antimicrobial and antiparasitic activities [ 20 , 21 ].…”