Floral structure in Acrocomia aculeata (Arecaceae): evolutionary and ecological aspects

Abstract

Acrocomia aculeata is an oleaginous palm widely distributed through the tropical and subtropical Americas that shows significant potential for agroindustrial use. Studies of floral structures can contribute to our knowledge of the evolutionary diversification of this genus and ecological aspects of its species as well as assist management and domestication programs. With the objective of characterizing the morphoanatomy of the flowers of A. aculeata, 20 inflorescences were collected in each of three natural populations growing in the northern region of Minas Gerais State, Brazil. Flowers at anthesis were evaluated biometrically and using standard plant anatomical procedures, and observed under light and scanning electron microscopy. The flowers showed wide biometric variability that was influenced by the collection area, the individuals examined, and the positions of the flowers on the inflorescence. Staminate flowers can have two whorls of petals, small anthers, and vestigial structures, with the development of an infertile carpel and rudimentary ovules. Defenses against herbivory include the presence of raphides in the anthers and pistillate flowers, fiber bundles, stegmata, and idioblasts containing phenols and raphides. Pollinators are attracted by the liberation of intense odors produced by osmophores located in the corolla, with pollen being the principal resource offered. Phenotypic plasticity, the structures involved in defending against herbivores and attracting pollinators, the numbers of flowers, and flowering synchrony contribute to the reproductive success of this species. The short period during which the stigmas remain receptive determines synchronous fertilization within the inflorescence.

Acrocomia spp.: neglected crop, ballyhooed multipurpose palm or fit for the bioeconomy? A review

“…This limitation is caused by a spatially constrained dispersion of pollen and seeds and probably also by asynchronous flowering (Abreu et al 2012;Coelho et al 2018;Lanes et al 2015;Portela et al 2020). However, synchronized fertilization throughout the inflorescence was observed in A. aculeata, evidencing no relation with irregular fruit abscission (Mazzottini-dos-Santos et al 2015a). An analysis of gene flow and migration indicated that geographically proximal populations have high migration rates, which influence mutation and variability in populations, possibly increasing their genetic homogeneity (Portela et al 2020).…”

“…From 2011 to 2015, initial studies on phylogenetic aspects of acrocomia were published. These revealed new evidence in relation to its taxonomic classification (Eiserhardt et al 2011;Ludeña et al 2011), floral structure, and fruit development (Mazzottini-dos-Santos et al 2015aMontoya et al 2016). Findings were published for assisting future plant breeding programs, including a study on the biometric and phytochemical traits of fruits and oils (Ciconini et al 2013).…”

“…A. aculeata is a monoecious species (both male and female flowers are present in the same inflorescence) with marked protogyny, which flowers from October to December (Scariot et al 1991;Mazzottini-dos-Santos et al 2015a). Flowers present high genetic and biometric variability and phenotypic plasticity (Mazzottini-dos-Santos et al 2015a).…”

Temperature as the main factor affecting the reproductive phenology of the dioecious palm Mauritiella armata (Arecaceae)

“…Lower averages of all evaluated parameters were observed at the apex position. The greater abundances of structures (rachis and flowers) in the basal region may be related to the greater resource availability there, as differential access to nutritional resources can influence flower distribution, morphology, and functioning (Mazzottini-dos-Santos et al 2015). The individuals evaluated had larger staminate inflorescences with larger numbers of flowers than pistillate inflorescences, although the pistillate flowers were larger.…”

Study of storage condition on the physicochemical properties of biodiesel derived from macaúba palm (Acrocomia aculeata) oil using multivariate analysis

“…Exmart, Arecaceae, (macaúba) is an arborescent, thorny, species of palm tree, more than 16 meters high that can be found in the tropical and subtropical regions of the Americas (da Motta, et al 2002), commomly found in the North of the state of Minas Gerais, a region where the cerrado biome is predominant (Oliveira, et al 2012). The oil extracted from macaúba fruits has considerable economic potential; and in addition to being a species used for ornamentation, natural medicine, and as food ingredient, it has been studied for use in the energy and industrial sectors, including the production of Biodiesel (C. Mazzottini-dos-Santos, et al 2014). The macaúba is a native and perennial species found in several Brazilian tropical forests.…”