Anatomical, histochemical, and developmental approaches reveal the long-term functioning of the floral nectary in Tocoyena formosa (Rubiaceae).

Autor: Izquierdo JV; Instituto Multidisciplinario de Biología Vegetal, Universidad Nacional de Córdoba (CONICET), Córdoba, X5000ZAA, Argentina.; Laboratório de Ecologia da Polinização e Interações (LEPI), Departamento de Biodiversidade e Bioestatística, Instituto de Biociências de Botucatu, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (Unesp), Botucatu, SP, Brazil., Canaveze Y; Departamento de Botânica, Instituto de Biologia, Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil. yve.canaveze@yahoo.com.br., Machado SR; Laboratorio de Pesquisas em Anatomia Vegetal, Departamento de Biodiversidade e Bioestatística, Instituto de Biociências de Botucatu, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (Unesp), Botucatu, SP, Brazil., Amorim FW; Laboratório de Ecologia da Polinização e Interações (LEPI), Departamento de Biodiversidade e Bioestatística, Instituto de Biociências de Botucatu, Universidade Estadual Paulista 'Júlio de Mesquita Filho' (Unesp), Botucatu, SP, Brazil. felipe.amorim@unesp.br.
Jazyk: angličtina
Zdroj: Die Naturwissenschaften [Naturwissenschaften] 2024 Apr 22; Vol. 111 (3), pp. 25. Date of Electronic Publication: 2024 Apr 22.
DOI: 10.1007/s00114-024-01909-5
Abstrakt: Tocoyena formosa has a persistent floral nectary that continues producing nectar throughout flower and fruit development. This plant also presents an intriguing non-anthetic nectary derived from early-developing floral buds with premature abscised corolla. In this study, we characterize the structure, morphological changes, and functioning of T. formosa floral nectary at different developmental stages. We subdivided the nectary into four categories based on the floral and fruit development stage at which nectar production started: (i) non-anthetic nectary; (ii) anthetic nectary, which follows the regular floral development; (iii) pericarpial nectary, derived from pollinated flowers following fruit development; and (iv) post-anthetic nectary that results from non-pollinated flowers after anthesis. The nectary has a uniseriate epidermis with stomata, nectariferous parenchyma, and vascular bundles, with a predominating phloem at the periphery. The non-anthetic nectary presents immature tissues that release the exudate. The nectary progressively becomes more rigid as the flower and fruit develop. The main nectary changes during flower and fruit development comprised the thickening of the cuticle and epidermal cell walls, formation of cuticular epithelium, and an increase in the abundance of calcium oxalate crystals and phenolic cells near the vascular bundles. Projections of the outer periclinal walls toward the cuticle in the post-anthetic nectary suggest nectar reabsorption. The anatomical changes of the nectary allow it to function for an extended period throughout floral and fruit development. Hence, T. formosa nectary is a bivalent secretory structure that plays a crucial role in the reproductive and defensive interactions of this plant species.
(© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)
Databáze: MEDLINE
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