Pollen Morphological and Morphometric Analysis in species of the Aeschynomeneae and Adesmieae Tribes (Faboideae, Fabaceae)

LATTAR, E. C.; BÓBEDA, G.; ZINI, L. M.

PALYNOLOGY

AMER ASSOC STRATIGRAPHIC PALYNOLOGISTS FOUNDATION

Año: 2019

0191-6122

The aim of this study was to analyze the pollen morphological diversity among nineteen species of the Adesmieae and Aeschynomeneae tribes with the purpose to evaluate its importance for the taxonomical delimitation of the Argentinean species and its systematic significance. Observations and measurements were performed on acetolyzed pollen grains. The samples were examined under light and scanning electron microscopes. Principal components analysis (PCA) and Conglomerates Analysis were performed for quantitative morphological variables. Adesmieae tribe is stenopalynous while Aeschynomeneae tribe is eurypalynous, pollen grains are 3-colporate, they have lolongate, circular or lalongate endoapertures, semitectate-reticulate or tectate-perforate, fossulate, supra-rugulate exine, small to large size, and suboblate to prolate shapes. A key was made to identify and distinguish species of Adesmia, Aeschynomene, Chaetocalyx, Discolobium, and Poiretia. Exine sculpture and structure, operculum presence, exine thickness, pollen shape, endoaperture shape, and pollen size all had taxonomic importance to distinguish the species inhabiting Argentine. The groupings recognized in recent classifications were hard to delimit on the basis on the palynological knowledge at this time since there are different pollen types but various of them occur among the three subclades. A framework for future evolutionary analyses within the dalbergioid clade was thus provided.