Morpho–anatomical and ultrastructural analysis of extrafloral nectaries in Inga edulis (Vell.) Mart. (Leguminosae)

Abstract

The presence of extrafloral nectaries (EFNs) between leaflets is an usual feature in Inga edulis (Vell.) Mart. (Leguminosae). Extrafloral nectaries are secretory structures involved in production of nectar and which serve in the protection of plants against herbivores through association with ants. This study aimed to characterize the EFNs of I. edulis at different developmental stages and describe their morphology, histochemistry and ultrastructure. Leaf fragments, containing secretory structures, were processed according to standard methods for light, scanning and transmission electron microscopy. The EFNs were classified into three stages based on morphology: pre‐secretory, secretory and post‐secretory. The pre‐secretory stage occurs in young leaves, whereas secretory and post‐secretory stages occur in developed and senescent leaves, respectively. The EFNs possess a concave surface and a central cleft in which nectar is accumulated and which was not observed in pre‐secretory EFNs. Histochemical tests identified the presence of sugars, proteins, phenolic compounds, mucilage and lipids at all developmental stages of the EFNs. Calcium crystals were identified in all tissues and stages of the EFNs. The secretory cells of the EFNs exhibit a granular cytoplasm, small vacuoles, prominent nuclei, smooth endoplasmic reticulum and mitochondria. Post‐secretory stage EFNs exhibited intense cytoplasmic degradation and the presence of microorganisms. The performance of EFNs of I. edulis appear to follow the leaf development.

Extrafloral nectary development, characterization and secretion in Chamaecrista debilis and Chamaecrista desvauxii var. langsdorfii (Leguminosae, Caesalpinioideae)

“…Although the mature fully-developed EFNs of C. debilis and C. desvauxii var. langsdorfii are morphologically distinct, they do share same morphoanatomical similarities between them and among other EFNs described for Chamaecrista (Bhatacharyya and Maheshwari 1971, Francino et al 2006, Melo et al 2010, Coutinho et al 2012, Coutinho and Meira 2015, Silva et al 2017, Rando et al 2019 as well as to other genera of the subfamily Caesalpinioideae (Elias 1972, Bentley and Elias 1983, Melo et al 2010, Pireda et al 2018, Marazzi et al 2019). In C. debilis and C. desvauxii var.…”

“…Studies on the development of EFNs in Caesalpinioideae are scarce as most studies are focused on the morphoanatomical characterization of the mature structure or ecological role played by such glands (Koptur 1994, Melo et al 2010, Marazzi et al 2013a, 2019, Pireda et al 2018). Without ontogenetic studies of EFNs unraveling the evolution of secretory structures is tiresome.…”

“…Several studies have focused on the topography, morphology, anatomy, exudate composition and ecology of the EFNs (Bentley and Elias 1983, Oliveira and Leitão‐Filho 1987, Heil et al 2005, Rocha et al 2009, Delgado et al 2011, Marazzi et al 2013a, Koptur 2014, Pireda et al 2018). The great topographical and structural variability of EFNs as well as their wide occurrence in several taxa has been already demonstrated (Bentley and Elias 1983, Koptur 1992, Nicolson et al 2007, Melo et al 2010, Dalvi et al 2013, Weber and Keeler 2013, Weber et al 2015).…”

True nectar or stigmatic secretion? Structural evidence elucidates an old controversy regarding nectaries in Anthurium

“…For instance, sucrose transport from the symplast to the apoplast, if against a concentration gradient, occurs via antiporters (Vassilyev, 2010) and depends on ATPase activity. Therefore, as pointed out by Pireda et al, 2018), calcium regulation appears to be crucial to nectar secretion, which may explain why calcium oxalate crystals have been reported next to or inside nectar-secreting tissues in several plant species (See Paiva et al, 2007 and references therein;Konarska, 2014;Pereira et al, 2018). Accordingly, the presence of abundant crystals in the distal portion of A. andraeanum tepals must be regarded as another piece of evidence of nectar secretion capacity.…”

Obtenção de micro e nanocelulose a partir de biomassa lignocelulósica de resíduo do ingá-cipó (Inga edulis Mart.) via tratamento químico

“…uma árvore frutífera perene, pertencente à família Fabaceae (Leguminoseae). Esta espécie pode ser encontrada em diversos biomas do Brasil, como Mata Atlântica, Caatinga, Cerrado e Amazônia, sendo o estado do Amazonas o principal produtor nacional (FREITAS et al, 2018;PIREDA et al, 2018). A árvore de Ingá-cipó, em sua fase adulta, possui uma altura de 15 a 40 m, com o diâmetro de tronco de 30 a 60 cm e uma copa densa.…”