Palynological Studies of Three Taxa and One F1 Hybrid in the Genus Talinum Adans

Abstract

Acetolysed pollen grains of Talinum paniculatum (Jacq.) Gaertn., Talinum triangulare (Jacq.) Willd. pink petals, Talinum triangulare (Jacq.) Willd. white petals and Talinum triangulare (Jacq.) Willd. pink and white petals F1 hybrid were studied in order to document their morphological structures and ascertain features of taxonomic significance among them. All the taxa have generic features which support their classification as a genus as well as distinct features which ascertain their individuality. Generic features include monad pollen unit, acolpate and monocolpate pollen grains as well as circular and ovate pollen shapes. The delimiting features include additional dyads pollen units in T. triangulare white petal and the F1 hybrid of T. triangulare pink and white petals, quadrangular pollen shape in T. paniculatum, bicolpate pollen grain in the F1 hybrid, tricolpate pollens in T. triangulare white petal and T. paniculatum, tetracolpate pollens in T. triangulare pink petal and T. paniculatum and pentacolpate pollen grains in T. paniculatum only. The shape of the pores in T. paniculatum also separated it from the varieties and hybrid of T. triangulare. Based on the pollen size, the pollens of T. paniculatum are Media (25 - 50 µm) while those of the two varieties of T. triangulare and their F1 hybrid are Magna (50 - 100 µm). The taxa of Talinum in this study can be separated based on their palynological features.

Taxonomic importance of the palynological features of some members of family Leguminosae-Caesalpinioideae

“…Pollens with higher number of colpi were also reported in this study. The presence of higher number of colpi in any group of plants has been attributed to recent evolutionary advancement in such group of plants (Walker, 1976;Adedeji, 2005;Adedeji and Akinniyi, 2015;Arogundade and Lawal, 2018). Based on this assertion, the advancement of Senna over Cassia is established and this is as a result of the presence of more advanced pollen types-tetracolpate, pentacolpate and hexacolpate pollens, observed in the members of genus Senna and not in any of the members of Cassia.…”

“…The pollen diameter of the Senna species in this study is relatively higher than that of the members of the genus Cassia and this also supports the advancement of Senna over Cassia (Adedeji, 2005). Pollen grain sizes have been classified into various groups (Erdtman, 1952) and the classification has been adopted by many authors (Akinwusi and Illoh, 1996;Adedeji, 2005;Arogundade and Lawal, 2018). Based on this classification, the pollen size of all the species of Cassia and Senna in this study falls to the group media, with dimension between 25 µm and 50 µm.…”

“…The acetolytic method described by Erdtman (1960) and as modified by Arogundade and Lawal (2018) The acetolytic method includes series of centrifugation at 350 rpm for 20 minutes at each stage. The first stage involved the maceration of anthers in absolute ethanol.…”

“…Palynological evidences have proven useful at all taxonomic levels because the structure of the pollen wall which is usually being employed in the study is not affected by environmental factors Nnamani and Onu (2014). Palynological characters have therefore been variously employed in the taxonomy of species of plants, forensic sciences, crime site detection, archaeology, paleoecology, delimitation of closely related or sympatric species, valuable in phylogenetic inferences (Nyananyo, 1992;Akinwusi and Illoh, 1996;Edeoga et al, 1998;Adedeji, 2005;Arogundade and Adedeji, 2009;Simpson, 2010, Arogundade andLawal, 2018). According to Acharya et al (2011), there are still a lot of taxonomic work to be done at the genera and specific levels of the subfamily Caesalpinioideae.…”