Extrafloral nectaries of annatto ( Bixa orellana L.): anatomy, nectar composition and activity during organ development

Abstract

Th is study aimed to anatomically characterize the extrafl oral nectaries (EFNs) of annatto (Bixa orellana) and determine the composition of its nectar in order to better understand their structure and function during organ development. Standard light and scanning electron microscopy techniques were used for anatomical analysis, and test-strips and a refractometer for determining nectar composition. Both receptacle and stem EFNs were found to possess similar anatomy and nectar composition, and to secrete from early to advanced developmental stages of the organs to which they are associated. EFNs consisting of uniseriate epidermis, nectariferous parenchyma and subnectariferous parenchyma were found located where vascular tissue is immersed. Some layers of nectariferous parenchyma exhibited sclerifi cation and cells with phenolic compounds or calcium oxalate druses were present. Nectar exuded by stomata was acidic, diluted and found to contain sugar. Th e anatomical and histochemical features of annatto EFNs ensure their integrity and nectar secretion function during the development of buds, fl owers and fruits.

Morphological and anatomical traits during development: Highlighting extrafloral nectaries in Passiflora organensis

“…Thus, the accumulation of calcium oxalate crystals in specialized cells such as idioblasts facilitates the transport of sucrose, due to the removal of calcium ions that would otherwise inhibit ATPase activity (Nepi, 2007). A correlation between the accumulation of oxalate crystals and nectar secretion has been observed in many other plant species and types of nectaries (Miranda et al, 2017).…”

“…They are reported in many species distributed in tropical, subtropical, and temperate regions, however, almost half of all the species bearing EFNs belong to Fabaceae, Passifloraceae, and Malvaceae families (Marazzi et al, 2013). EFNs are also commonly rich in calcium oxalate crystals, which are usually found in the parenchyma that lies underneath the secreting epidermis (Miranda et al, 2017; Paiva & Machado, 2006). Studies have shown that calcium oxalate crystals are reported within or in the region of EFNs of a wide diversity of angiosperms (Elias, 1983; Paiva et al, 2007; Schnell et al, 1963; Tilney & Van Wyk, 2004).…”

Comparing the contents, functions and neonicotinoid take-up between floral and extrafloral nectar within a single species (Hemerocallis citrina Baroni)

“…EFN secretion on Bixa orellana similarly reaches a peak on the mature floral buds, and ceases entirely by the time the flowers open (Bentley, 1977, de Miranda et al, 2017. Conversely, EFN is attractive to various insects that do not pollinate H. citrina, such as wasps, ants, mantises and flies.…”

A Cultura Indígena no Ensino de Química: Uma Proposta de Sequência Didática

“…A principal característica dessa classe é possuir sementes contendo dois ou mais cotilédones, que são as primeiras folhas que aparecem nas sementes quando se inicia o seu desenvolvimento. No caso do urucum, suas sementes possuem uma casca contendo uma substância vermelha denominada bixina, que vem da língua indígena, e significa vermelho (Filgueiras & Peixoto, 2002;Fabri & Teramoto, 2015;Miranda, Nery & Ventrella, 2017).…”