Waltheria encompasses about 60 species distributed in Brazil and Mexico. To improve the palynology of the genus, we analyzed 14 species occurring in the Brazilian State of Bahia. Pollen grains were acetolyzed and examined using light microscopy and scanning electron microscopy. Non-acetolyzed pollen grains were viewed by transmission electron microscopy. Th e results revealed two general pollen types based on exine ornamentation, such as reticulate and echinate, which are distinct with regard to (1) size and shape, (2) apertural type and number, (3) relative length of ectoapertures, and (4) thickening of the nexine compared to the sexine. An ultrastructural analysis of the pollen wall revealed a continuous foot layer and a compact and discontinuous endexine in most cases. Th e sexine consisted of heterogeneous columellae, which support a perforated semitectum (echinate type) or the semitectum was composed of perforations and muri-shaped thickening (reticulate type). Th ese results confi rm a high degree of pollen dimorphism in Waltheria associated with heterostyly.
This study aimed to identify the pollen types of 11 honey samples produced in apiaries of two cities in the State of Bahia, Brazil: Antônio Gonçalves (five samples) and Campo Formoso (six samples); to verify richness and diversity from each apiary and to compare the similarity among them. The samples were obtained from beekeepers according to the period of production and availability. The palynological analysis of these samples followed the standard procedures of melissopalynology with the use of acetolysis. The pollen types occurring in the honey samples were identified and at least 1,000 pollen grains per sample were counted to determine the frequency classes and the frequency of occurrence. Overall, 147 pollen types were detected, of which 143 are distributed in 35 botanical families. The most representative families concerning the number of pollen types were: Fabaceae (33), Asteraceae (18), Euphorbiaceae (11), Anacardiaceae and Malvaceae (09 types each), Rubiaceae (08) and Myrtaceae (07). The average value of pollen types per sample was 28.18. The genus that contributed the most was Mimosa L. (Fabaceae) with eight pollen types detected. The wealth of pollen types found revealed important information about the local flora which is explored by Apis mellifera. Therefore, it becomes an important tool to assist in the preservation and propagation of these plants and, consequently, increasing honey production.
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