Pollen Morphology of Selected Endemic Eudicots From the FLORAS Botanical Garden, Southern Bahia, Brazil

TL;DR

This study describes the pollen features of 12 endemic plant species from Brazil's Atlantic Forest, highlighting their diversity and ecological importance.

Contribution

The study provides new morphological data on pollen grains of 12 endemic eudicots from the FLORAS Botanical Garden in southern Bahia.

Findings

Pollen grains showed variations in shape, size, and exine ornamentation.

The study contributes to understanding the morphopalynological diversity of the Central Atlantic Forest Ecological Corridor.

Diagnostic pollen features can aid in the identification and conservation of threatened species.

Abstract

The Atlantic Forest is home to about 40% of Brazil's flora. Approximately 50% of the 17,975 species occurring in this biome are endemic, and many are threatened with extinction, such as brazilwood, Paubrasilia echinata (Lam.) Gagnon, H.C.Lima, & G.P.Lewis. Despite such importance, studies to characterize the pollen morphology of this rich flora have been unevenly distributed throughout this phytogeographic domain. Therefore, we aimed to describe the pollen morphology of 12 selected endemic species of eudicots from the FLORAS Botanical Garden, a remnant of the Atlantic Forest at intermediate stages of natural regeneration in southern Bahia State, Brazil. The analyzed species were Andira fraxinifolia Benth., Cranocarpus mezii Taub., Desmodium juruenense Hoehne, Eschweilera ovata (Cambess.) Mart. ex Miers, Himatanthus bracteatus (A.DC.) Woodson, Lantana undulata Schrank, Lundia longa (Vell.) DC., Mimosa caesalpiniifolia Benth., Ouratea cuspidata (A.St.‐Hil.) Engl., Paubrasilia echinata (Lam.) Gagnon, H.C.Lima & G.P.Lewis,
Solanum polytrichum
Moric., and Stigmaphyllon blanchetii C.E.Anderson. Flower buds were collected from exsiccatae of the GCPP herbarium. The pollen material was acetolyzed, measured, described, and photodigitalized using optical microscopy. Pollen grains were recorded in monads or polyads; small to large sized; spherical, prolate‐spheroidal, subprolate, or prolate; apolar or isopolar; with triangular, subtriangular, subcircular, or circular amb; 3‐colpate, 3‐colporate or pantoporate; and with psilate, (micro)reticulate, granulate, or scabrate exine. The descriptions revealed the local morphopalynological diversity, contributing to the understanding of the pollen florula of the FLORAS Botanical Garden and the Central Atlantic Forest Ecological Corridor.

This study describes the pollen morphology of twelve endemic species from the Atlantic Forest, revealing subtle morphopollinic variations. Diagnostic characters such as pollen shape, exine ornamentation, and amb type highlight the region's floristic diversity, providing valuable insights into the ecological and conservation significance of Brazil's threatened biodiversity.

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