Biometric Characterization of Fruits and Morphoanatomy of the Mesocarp of Acrocomia Species (Arecaceae

International Journal of Biology; Vol. 9, No. 3; 2017 ISSN 1916-9671 E-ISSN 1916-968X Published by Canadian Center of Science and Education Biometric Characterization of Fruits and Morphoanatomy of the Mesocarp of Acrocomia Species (Arecaceae) Suelen Alves Vianna1, Luiz Henrique Chorfi Berton1, Arnildo Pott2, Sandra Maria Carmello Guerreiro3 & Carlos Augusto Colombo1 1 Instituto Agronômico de Campinas, Centro de Recursos Genéticos Vegetais, São Paulo, Brazil Universidade Federal de Mato Grosso do Sul - Conselho de Pesquisa e Pós-Graduação, Instituto de Biociências, Campo Grande, MS, Brazil 2 3 Universidade Estadual de Campinas, Instituto de Biologia, São Paulo, Brazil Correspondence: Suelen Alves Vianna, Instituto Agronômico de Campinas, Centro de Recursos Genéticos Vegetais, São Paulo, Brazil. E-mail: suelen.loesch@gmail.com Received: May 22, 2017 Accepted: June 17, 2017 Online Published: June 21, 2017 doi:10.5539/ijb.v9n3p78 URL: https://doi.org/10.5539/ijb.v9n3p78 Abstract The genus Acrocomia (Arecaceae) is widely distributed in the Neotropics, without consensus on the number of species. The arboreal species are explored in their native countries. To subsidize better use of the observed variation in fruits of different species for product extraction, taxonomy, conservation and genetic improvement, our objective was to characterize biometrically the fruits and anatomically the mesocarp from natural populations of A. aculeata, A. intumescens and A. totai. We observed different colors of epicarp and mesocarp in A. aculeata and A. totai, while the fruits of A. intumescens were light green or yellowish. The fruits of A. aculeata showed diameter considered large (3.9-4.6 cm) and the highest dry mass (26.3-33.5 g), A. intumescens presented intermediate diameter (3.1–3.9 cm) and mass (11.5-18.8 g), and A. totai had the smallest diameter (2.2-3.0 cm) and mass (4.1-11.4 g). The morphoanatomical analysis of the mesocarp did not distinguish the three species. However, it revealed the presence of useful compounds for human consumption and with economic potential, such as oil in the parenchyma cells, mucilage, starch and phenolic compounds. We concluded that the mesocarp anatomy is not useful for taxonomy, but the biometric variation is, as well as variation within species can be applicable in conservation and genetic improvement. Keywords: biofuel, palm, plant anatomy, plant products, plant taxonomy Resumo O gênero Acrocomia (Arecaceae) é amplamente distribuído no continente americano não havendo consenso sobre o seu número de espécies, sendo as de porte arbóreo comercialmente exploradas nos países onde ocorrem. Com intuito de gerar subsídios para melhor aproveitar a variação observada nos frutos das diferentes espécies para taxonomia, conservação e melhoramento genético das espécies, o objetivo do presente estudo foi caracterizar biometricamente os frutos e anatomicamente o mesocarpo de populações naturais de A. aculeata, A. intumescens e A. totai. Foram observadas diferentes colorações de epicarpo e do mesocarpo em A. aculeata e A. totai, enquanto os frutos de A. intumescens são verde-claros ou amarelados. Os frutos de A. aculeata têm diâmetro considerado grande (3,9-4,6 cm) e de maior massa seca (26,3-33,5 g), A. intumescens apresentou diâmetro e massa intermediários dos seus frutos (3,1–3,9 cm e 11,5-18,8 g, respectivamente). A. totai apresentou os menores diâmetro e massa de frutos (2,2-3,0 cm e 4,1 -11,4 g, respectivamente). A análise morfoanatômica do mesocarpo não diferenciou as espécies do estudo. No entanto, revelou a presença de compostos úteis para consumo humano e potencial econômico dos compostos identificados, como a presença de óleo nas células do parênquima, mucilagem, amido e compostos fenólicos. Conclui-se que a anatomia do mesocarpo não é útil para taxonomia e que variação biométrica entre as espécies pode ser empregada para este fim, assim como a variação dentro das espécies pode ser útil para fins de conservação e melhoramento genético. Palavras-chave: biocombustível, palmeira, anatomia, produtos vegetais, taxonomia 78 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 1. Introduction The genus Acrocomia is Neotropical and the number of species is not yet well taxonomically well resolved. According to Henderson et al. (1995), only two species are attributed to the genus: A. aculeata (Jacq.) Lodd. ex Mart. and A. hassleri (Barb. Rodr.) W.J. Hahn, the first having large size, widely distributed along Central and South Americas, and the second, small, restrict to some areas of Cerrado of Brazil and part of Paraguay. Lorenzi et al. (2010) recognize seven species in the genus, six occurring in Brazil: A. aculeata, A. intumescens Drude and A. totai Mart., of arboreal size, and A. hassleri, A. glaucescens Lorenzi and A. emensis (Toledo) Lorenzi, of small size; and A. crispa (Kunth) C.F. Baker ex Becc., of arboreal size, endemic to Cuba. Furthermore, according to The Plant List (2013), all previously cited species are considered valid plus A. media O.F. Cook., endemic to Porto Rico and Virgin Isles, also of arboreal size, but Proctor (2005) mentions it as a lower plant, with larger leaves and smaller spathe compared to A. aculeata. The species of Acrocomia are utilized for several purposes. The palms are utilized as ornamental species in different countries of occurrence (Lima, 1994; Moraes, 2004; Silva, 2012). In Mexico, Bolivia and Brazil the roots are utilized as medicine (Amorozo & Gély, 1988; Hernández et al., 2011; Moraes, 2004). In countries of Central America, Mexico, Venezuela and Brazil it is common the utilization of sap of the stipe to prepare an alcoholic drink (Balick, 1984; Bran, 2013; Corrêa, 1984; Hernández et al., 2011; Lentz, 1990; Plotkin & Balick, 1984). The leaves are utilized for rooves or as raw material to obtain fibers for production of lines, ropes and nets, and as good quality forage (Moraes, 2004; Pott, 1986). Although all parts are utilized, the fruits have the highest diversity of economic exploration, being utilized for human fresh or processed food, presenting good nutritional quality and medicinal purposes (Hernández et al., 2011; Ramos et al., 2008). Nevertheless, the highest interest in exploration of the fruits is for their potential for production of oil of the mesocarp (pulp) for biofuel, over 4,000 Kg/ha/yr, and of the nut oil for cosmetics. Among the recognized species, in Brazil, three are explored for extractivism for presenting fruits of commercial interest: A. aculeata, popularly known as macaúba, with occurrence in various states of Brazil; A. intumescens, locally called macaíba, endemic to the Northeast region, occurring in areas of the called Zona da Mata (forest zone)and in altitude forests; and A. totai, known as bocaiúva, distributed in most part of the state of Mato Grosso do Sul, associated to areas de Cerrado and Pantanal (Lorenzi et al., 2010; The Plant List, 2013). The three species can be morphologically distinguished, mainly by the characteristics of the stipe: A. aculeata has very spinescent stipe and presence of the rests of leaf sheath; A. totai presents lower number of spines and sporadically the rests of the leaf sheath; and A. intumescens has spines only when young, presenting swelling in the middle of the stipe and without rests of the leaf sheath (Lorenzi et al., 2010). The fruit is of the drupe type, derived from superior ovary, characterized by the presence of stony epicarp (peel), fleshy mesocarp (pulp) and stony endocarp (Esau, 1977). The fruits of the species of Acrocomia are globose, present hard epicarp, strongly adhered to the mesocarp when young, and generally brittle, easily detaching from the mesocarp when ripe. The mesocarp is mucilaginous, with large quantity of fibers. The endocarp is woody and thick (Dransfield et al., 2008; Lorenzi et al., 2010). The three studied species are explored for consumption or commercially. The fruits of A. intumescens in the Northeast region and the fruits of A. totai in the state of Mato Grosso do Sul are explored by local communities for consumption of pulp and fresh or processed nut in several types of foods, such as meal, ice cream, cake and others. Some of the products are sold by these communities as source or complement of family income. The species A. aculeata has been explored, mainly in the state of Minas Gerais, for extraction of oil of pulp and nut for production of biofuel and cosmetics. Historically, the oil of A. aculeata was used for street lightning of important old mining towns, such as Ouro Preto and Mariana, Minas Gerais. Although A. aculeata nowadays is the species most utilized for production of biofuels, containing between 37 and 78% of oil in the mesocarp (Berton, 2013; Conceição et al., 2012), the other species also present potential for oil production. Acrocomia intumescens presents between 34 and 41% of oil in the mesocarp (Bora and Rocha 2004; Conceição et al. 2012). The species A. totai presents oil content in the mesocarp between 14 and 31% (Ciconini et al., 2013; Conceição et al., 2012; Hiane et al., 2005). Considering that the economic potential of the species of Acrocomia is based, mainly, in the exploration of its fruits, studies on biometric characterization of fruits of different species from different regions are of great importance. The biometric characterization of fruits is fundamental to subsidize conservation and exploration of plant resources, since such data allow to estimate the productivity and to sort more homogeneous seed lots and, consequently, with more uniformity and vigor (Moura et al., 2010). It is also a useful tool for detection of genetic 79 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 variability within populations of a same species and the relations between this variability and environmental factors, information useful in genetic programs (Carvalho et al., 2003). The tropical arboreal species present striking differences regarding fruit size, number and size of seeds (Silva et al., 2007), so the biometry of fruits can be useful for taxonomic distinction, as doubts persist yet upon the most adequate number of species for the genus Acrocomia. However, most botanical classifications are based only on morphological data, many of them presenting variation of genotype vs. environment nature. So, mistakes may occur, what demonstrates the importance of utilization of other techniques which could help to split species. The study of fruit anatomy is a valuable tool for the classification of the type of fruits and, consequently, for Taxonomy (Souza et al., 2012), for practically not varying under environmental interference, and can also provide valuable data for identification of plant products (Vaughan, 1960). The histochemical detection of substances in fruits is of great importance not only for taxonomy but also for identification of active principles and other substances which can be utilized by the industry (Dôres, 2007). The commercial value of the fruits and the types of industrial processes needed, for example, for extraction of oil are determined by the nature and anatomical structure of fruits (CETEC, 1983). The studies of fruits involving species of Acrocomia are yet scarce. So, our work was carried out with the objective to characterize biometrically fruits of the three arboreal species of Acrocomia of highest commercial interest with occurrence in Brazil and with great potential for utilization in the other countries where they occur, as well as to characterize anatomically the mesocarp to verify which tissue and or structure of the mesocarp contains the oil and if it is possible to perform the quantification of such cells and or structures aiming its adoption as selection criterion for purposes of genetic improvement. 2. Method 2.1 Sampling Area and Fruit Biometry The chosen species of Acrocomia are in accordance with Lorenzi et al. (2010). The individuals selected for our study are from different regions of Brazil. The individuals of A. aculeata from two natural populations in a transition area between Cerrado and Mata Atlantic forest in the municipality of Itapira, São Paulo. The individuals of A. intumescens were collected from a population in an area of Atlantic forest in the metropolitan region of Recife, Pernambuco, and the plants of A. totai were selected from two native populations of the Pantanal in the municipality of Corumbá, Mato Grosso do Sul. We sampled 30 fruits at random from ten individuals of each population (Figure 1). According to Manfio et al. (2011), evaluation of four fruits in a population is sufficient to assess the studied characteristics. Figure 1. Area of occurrence and collection points of the three studied species of Acrocomia in Brazil The fruits were measured as for their external longitudinal diameter (length), external transversal diameter (diameter) and individually weighed for determination of fresh mass and dry mass given by drying in oven with air circulation at 58oC, until constant weight. The percentage of moisture in the pulp was obtained by difference 80 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 between fresh mass and dry mass, divided by fresh mass (Moura, 2010). We calculated the length/diameter ratio (C/D) of the fruits, regarding that the ratio C/D < 1 indicates flat shape, C/D > 1 is ovoid, and the ratio C/D = 1 means globose (Sacramento et al., 2003). The obtained data were analyzed by univariate statistics, covering measures of position (medium, minimum and maximum) and of dispersion (standard deviation, coefficient of variation), as well as distribution of frequency. We performed analysis of variance (ANOVA) with Tukey’s posttest, at 5% of probability. The biometric characteristics of fruits of the studied species of Acrocomia were compared as for their diagnostic potential for taxonomy and genetic improvement, using groupment analysis. We analyzed the four main characteristics related to productivity: external longitudinal diameter, external transversal diameter, and fresh and dry masses. The data were distributed in classes and then tabulated in form of binary matrix described as presence (1) or absence (0) and then submitted to groupament analysis utilizing the algorithm UPGMA and the Euclidian distance as measure of similarity among sampling units using the software PAST (Hammer et al., 2001). The stability dos groupments was tested applying the procedure of resampling by 10000 bootstraps. 2.2 Morphoanatomy of the Mesocarp Three fruits of each population were collected for analyses of anatomy, fixed with FAA70 for 48 hours and stored in ethylic alcohol 70%. Next, we removed a small piece of the central region of the fruit with a band-saw and then dehydrated it in ethylic series. Afterwards, the material underwent a pre-infiltration in different concentrations of a solution of synthetic resin (Historesin ® Leica) and alcohol and then immersed in pure synthetic resin, sectioned in rotative microtome and stained with toluidine blue 0.05% in acetate buffer 0.1 M (pH 4.7) (O’Brien et al., 1964). We performed histochemical tests utilizing Sudan IV for detection of total fats (Pearse 1985), Lugol for detection of starch (Gerlach, 1984), Ruthenium red (Jensen, 1962) for detection of pectic substances, polysaccharides and acid mucilage and iron III chloride (Johansen, 1940) for detection of simple phenols. The documentation of the slides set of the optic microscopy was obtained under photomicroscope Olympus BX 51 with system and coupled image capture model DP71. 3. Results and Discussion 3.1 Biometric Characterization of Fruits The fruits of A. aculeata and A. totai present different peel and pulp colors, even in individuals of the same population. The fruits of A. intumescens presented lower variation and are generally light green or yellowish when ripe. It is also possible to perceive visually the contrast of size among fruits of the different species (Figure 2). Photos Acrocomia aculeata : Berton, L.H.C. Figure 2. Morphological variation of number of seeds, color of peel and color of pulp of: a Acrocomia aculeata, b A. intumescens and c A. totai. 81 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 To demonstrate graphically the variability of characteristics within and between the studied species of Acrocomia, each measured characteristic was evaluated considering the data of the three species altogether and then determined classes of distribution of data. The data of absolute frequency are represented in the graphs by the columns and the relative frequency (%) of data distribution of each characteristic within each species is represented by lines (Figure 3). a b c d Figura 3. Distribution of classes of data of diameter, length, fresh mass and dry mass of Acrocomia aculeata, A. intumescens and A. totai. Regarding diameter, most sampled fruits belong to the class “large”, between 4.0 and 4.7 cm. Although occurring overlap of part of the values in some points of the distribution, the separation of peaks is quite clear, i.e., of the highest frequency of each biometric characteristic within species in the distribution. Most fruits of A. aculeata (83.33%) have diameter considered large, A. intumescens most fruits (71.67%) with intermediate diameter (3.1 – 3.9 cm) and A. totai has most fruits (95%) with small diameter, between 2.2 and 3.0 cm (Figure 3 a). Concerning length, most part of data was concentrated in class “large”, measuring 3.9 to 4.6 cm. As can be observed in Figure 3 b, there was data overlap of A. intumescens and A. totai, with great part of their fruits with “medium” size (3.0 to 3.8 cm). However, the highest frequency of fruit length in A. totai (58.33%) was concentrated in the class “small” with fruits measuring between 2.1 and 2.9 cm, and A. aculeata and A. intumescens with most fruits (73.33 and 56.67%, respectively) distributed in class “large”. Most sampled fruits, considering the three species together, presented fresh mass between 16.5 and 26.2 g, being represented in the class “light”. There was overlap of part of the fruits of A. aculeata and A. intumescens (43.33%) in the class of fruits with fresh mass “medium”, with weight between 26.3 and 35.9 g. In A. totai the fruits were distributed between the classes “very light” (6.9 – 16.4 g) and “light”, most part concentrated in the class “light” (53.33%). Most data of fresh mass of A. aculeata was concentrated in class “heavy” (45%) with fruits weighing between 40 and 45.5 g (Figure 3 c). In spite of the observed overlap of data of dry mass in the distribution of 82 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 classes, the formation of three peaks is well evident, each one indicating the highest frequency of data of dry mass determined within each species (Figure 3 d). Acrocomia aculeata has most fruits in the class “heavy” (55%), with dry weight between 26.3 and 33.5 g. Acrocomia intumescens has the highest frequency of fruits (71.67%) with weight between 11.5 and 18.8 g concentrated in class “light”, and A. totai presents most fruits in the class “very light” (78.33%), weighing between 4.1 and 11.4 g. The morphological diversity both within and between analyzed species of Acrocomia was with utilization of the distribution in classes of the evaluated biometric characteristics. The variability within each species was explained by the presence of fruits in different classes of each characteristic. For example, A. aculeata has fruits distributed into four of the five classes established for fresh mass (Figure 3 c). The variability among species graphically demonstrated by the peaks of distribution of the biometric characteristics within each species, such as the diameter classes forming three peaks, each peak representing one well defined species, each one covering a certain class of distribution (Figure 3 a). The fruits of A. aculeata showed the largest mean diameter and length (4.13 ± 0.27 cm and 4.01 ± 0.29 cm, respectively), followed by A. intumescens (3.69 ± 0.29 cm and 3.88 ± 0.27 cm, respectively) and A. totai with the lowest mean fruit size, 2.72 ± 0.24 cm diameter and 2.84 ± 0.30 cm length (Table 1). The highest mean fresh mass of the fruit was also found in individuals of A. aculeata (39.04 ± 7.06 g). Acrocomia intumescens has mean fresh mass of 29.08 ± 6.87 g, and A. totai, the lowest mean value of fresh mass (16.39 ± 4.16 g), compared to the other studied species. The highest mean dry mass value also occurs for A. aculeata (26.69 ± 4.54 g), intermediate value in A. intumescens (17.27 ± 3.33 g) and the lowest dry mass in A. totai (9,42 ± 2,83 g) (Table 1). Table 1. Biometric characteristics of fruits of Acrocomia aculeata, A. intumescens and A. totai: lower limit (LL), upper limit (UL), mean, standard deviation (σ) and coefficient of variation (CV%) LL UL Mean σ CV% Acrocomia aculeata External longitudinal diameter (cm) 3.44 4.62 4.01 0.29 7.28 External transversal diameter (cm) 3.35 4.72 4.13 0.27 6.50 Fresh mass of the whole fruit (g) 23.55 55.16 39.04 7.06 18.09 Dry mass of the whole fruit (g) 14.34 40.91 26.69 4.54 17.00 Moisture of the fruit (%) 8.96 44.30 31.05 8.49 27.34 Ratio C/D 0.83 1.09 0.97 0.05 4.67 Acrocomia intumescens External longitudinal diameter (cm) 3.10 4.40 3.88 0.27 7.08 External transversal diameter (cm) 3.20 4.25 3.69 0.29 7.86 Fresh mass of the whole fruit (g) 1894 54.92 29.08 6.87 23.61 Dry mass of the whole fruit (g) 9.49 27.00 17.27 3.33 19.29 Moisture of the fruit (%) 2870 73.82 39.62 7.30 18.43 Ratio C/D 0.95 1.26 1.05 0.06 5.52 Acrocomia totai External longitudinal diameter (cm) 2.07 3.65 2.84 0.30 10.66 External transversal diameter (cm) 2.17 3.30 2.72 0.24 8.90 Fresh mass of the whole fruit (g) 6.89 25.40 16.39 4.16 25.39 Dry mass of the whole fruit (g) 4.10 17.57 9.42 2.83 30.06 Moisture of the fruit (%) 21.05 65.04 42.53 7.79 18.32 Ratio C/D 0.74 1.43 1.05 0.10 9.41 Acrocomia aculeata presents ratio C/D of 0.97 and A. intumescens and A. totai have 1.05, i.e., the fruits of the three studied species present ratio C/D close to 1, evidencing globose shape (Table 1). Moisture content of fruits also varied among species, A. totai presenting the highest content (42.53 ± 7.79%), followed by A. intumescens (39.62 ± 7.30%) and the lowest in fruits de A. aculeata (31.05 ± 8.49%) (Table 1). The values can vary according to the ripening stage of fruits, form of harvest and preservation time. Significant differences (p < 0.05) were detected among the means of length, diameter, fresh mass and dry mass of fruits, i.e., the obtained results rejected the hypothesis of equality among means, demonstrating the existence of 83 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 biometric variation among species, A. aculeata standing out for the highest values for all cited biometric characteristics, A. totai, the lowest values and A. intumescens intermediate values (Figure 4). * Same letters do not differ statistically at 5% probability (p < 0, 05) test de Tukey. Figure 4. Biometric characteristics of fruits of Acrocomia aculeata, A. intumescens and A. totai. The four main biometric characteristics of fruits (diameter, length, fresh and dry mass) utilized for groupment analysis resulted in separation of the studied species of Acrocomia, as illustrated in Figure 5. Figure 5. Groupment analysis obtained by Euclidian distance and UPGMA, based on the characteristics diameter, length, fresh and dry masses of fruits of the three studied species of Acrocomia. 84 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 The analysis resulted in closeness of A. aculeata and A. intumescens and separation of A. totai from both, what can be explained by the values remarkably lower of all evaluated biometric characteristics found in A. totai. Figure 3 illustrates that A. totai presents the peaks with highest frequencies of the samples of each evaluated characteristic well separated from the other species, and that A. aculeata and A. intumescens present some peaks of highest frequency of similar data, as well as overlap of samples in a same class, e.g. frequency distribution of length data (Figure 3 b), where A. aculeata and A. totai have the highest frequency in the same class “large”. The fruit biometry data support the classification of Acrocomia proposed by Lorenzi et al. (2010). The main morphological characteristics which distinguish the studied species of Acrocomia are summarized in Table 2 (Figure 6). Table 2. Summary of the morphological characteristics of three species of Acrocomia. sp. Size Aa Arboreal Leaf Fruit length diameter (m) Stipe Cylindric, straight, with 1.9-3.0 Spines Stipe and leaves Fruit color Varied (cm) 3.0-5.0 remnants of base of dropped Habitat In general dry and open areas leaves Ai Arboreal Cylindric, swollen close to 2.4-3.0 the middle, smooth Stipe of young Greenish, plants light yellow May occur or not Varied 3.1-4.5 Atlantic forest and Altitude forest At Arboreal Cylindric, straight, without 2.0-2.6 remnants of base of dropped on stipe and leaves leaves 2.3-4.3 Dry and open areas * Aa: Acrocomia aculeata, Ai: Acrocomia intumescens and At: Acrocomia totai. The described data result from our observations and from the revision of Acrocomia by Lorenzi et al. (2010). a b c Figure 6. Adult individuals of a Acrocomia aculeata, b A. intumescens and c A. totai. 3.2 Anatomy of the Mesocarp The analyzed species of Acrocomia present similar morphoanatomy of the mesocarp, not representing a useful character for taxonomy of the genus (Figure 7 a-c). 85 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 The mesocarp is formed in most part by parenchymatic cells. Throughout the mesocarp can be observed large rounded cavities, with thin walls, irregularly distributed and frequently fused forming large spaces with irregular shapes (Figure 7 a-c). With the performed tests it was not possible to prove if these cavities (Figure 7 e, f) are the responsible for the high production of mucilage of the fruits, since the test for polysaccharides (Ruthenium red) was not positive. All over the mesocarp are also found bundles of non-vascular fibers and vascular bundles, the latter being involved by sclerenchymatic sheath. The vascular bundles are of similar size and are irregularly distributed throughout the mesocarp (Figure 7 d). Figure 7. Section of mesocarp: a Acrocomia aculeata, b A. intumescens, c A. totai, d detail of vascular bundle, e cavities with mucilage and f cavities with mucilage fused. Bar: 1mm (a-c), 100 µm (d), 500 µm (e, f). 3.3 Histochemical Tests The performed histochemical tests were also similar as for presence and quantity of the tested compounds, only differing in starch content, detected in highest quantity in A. intumescens, followed by A. aculeata, but absent in A. totai, and the highest presence of phenolic compounds in A. aculeata and A. totai. The assessed compounds and their intensity are summarized in Table 3. Table 3. Detected compounds in the mesocarp in the three species of Acrocomia. Species Total fats Starch Total polysaccharides Acrocomia aculeata ++ +/- - Simple phenols + Acrocomia intumescens ++ + - +/- Acrocomia totai ++ - - + + + Great quantity; - Not observed; + / - Observed in some individuals and not in others. 3.3.1. Total Fats Practically all parenchymatic cells of the mesocarp in all studied species contain oil as evidenced by positive reaction to Sudan IV, so, all species present potential for extraction. Oil occurs in parenchymatic cells of the mesocarp in form of lipid bodies, also called oleosomes or lipid droplets, which can present varied sizes depending on the species and or stage of the studied fruit parts. These organelles synthesize and store triacilglycerols (TAGs), 86 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 associated to proteins that delimit, i.e., compartimentamentalise the organelle, being responsible for the temporary storage and efficient of carbon of high energy (Horn et al., 2013, Ho et al., 2014). In case of this work, the oleosomes could not be observed in sections in the mesocarp, probably due to immersion process of the material in synthetic resin. In hand cuts made on material only fixed was possible to observe such organelles, however, due to the large quantity and overlap of oleosomes present, it was not possible to see the parenchymatic cells individually as it was also not possible to count the oleosomes (Figure 8 a, b). However, if altering the immersion technique of the material and the type of microscopy is possible to quantify and even measure the size of oleosomes. Ho et al. (2014) made quantification and measurement of oleosomes present in the embryo, in the mesocarp and in the nut of the oil palm (Elaeis guineensis Jacq.), finding differences between quantity and size of such organelles depending on the tissue and its development stage, however, utilizing other fixation and inclusion techniques and with use of transmission scanning microscope (Figure 9). a b c d e f Figure 8. Section of mesocarp in Acrocomia spp.: a oleossomes in the mesocarp, b detail of oleossome, c mucilage, d starch grains, e phenolic compounds detected with Ferric Chloride III, f cell with phenolic compound in detail, stained with toluidine blue. Bar: 100 µm (a, b, d, e), 1 mm (f) 3.3.2 Mucilage Although not having being visualized with the use of Ruthenium red, the quantity of mucilage present in fruits of Acrocomia is very high. Although the mucilage is concentrated in large cavities in the mesocarp, due to its great quantity it can permeate the epicarp, what was proven by visualization of the mucilage in the pulp because the alcohol in which fruits were preserved became very viscose (Figure 8 c). Mucilage is a macromolecular, complex carbohydrate, of varied composition (acid or neutral polysaccharides) according to the species, with hydrophilic properties (Sáenz et al., 2004). Due to its great capacity to absorb water, in whose presence it becomes viscose, acts in plants as a water reservoir (Cárdenas et al., 1998), having important physiological functions, such as reduction of transpiration in dry climates, water and nutritive substance storage, and protection against pests and pathogens (Alvarez et al., 1992; Fahn, 1979; Rocha et al., 2011). The production of mucilage in great quantity in fruits of Acrocomia spp. can suggest its role as adaptation to dry climates, where they are most frequent, or as chemical characteristic of species of the genus. Rocha et al. (2002), studying species of Hibiscus (Malvaceae) in xeric habitat, and Colonetti (2012), working on a cactus, verified the role of mucilage as storage substance and water retention. Yet, Silva and Potiguara (2009), analyzing the leaf histochemistry of Oenocarpus species (Arecaceae) from Amazonia, attributed the occurrence of mucilage, not to an ecophysiological adaptation, but to a probable characteristic of that palm group. 87 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 Since it was not possible to detect mucilage with the use of Ruthenium red in samples of our study, utilized for detection of total polysaccharides and acid mucilage (Jensen, 1962), we suppose that the mucilage present in the mesocarp of the studied species of Acrocomia is predominantly neutral. Gregory and Baas (1989, apud Rocha et al., 2011) suggested that different types of mucilage exert distinct functions, where water storage would be made by the acid fraction, with production peak during the Summer months, and the neutral fraction of the mucilage would be responsible for build-up of carbohydrates, with peak during Winter. Such finding supports the hypothesis of the presence of mucilage in the mesocarp of Acrocomia species exerting the function of water storage and retention. This can be even more feasible considering biochemical and anatomical studies on A. aculeata fruit development, with peak of mucilage accumulation in the mesocarp until natural fruit abscission (Montoya, 2013, Reis et al., 2012). And we point out that the abscission phase of fruits of species of the genus, indicating ripeness, occurs during the warmer months in Brazil. It is worth to highlight that mucilages, due to their viscose consistency in presence of water, have sticky and thickening properties, much utilized by the food industry in sweets and jams, and by the pharmaceutical industry for stability of emulsions and ointments, plus acting as dietetic fiber in the human organism promoting reduction of cholesterol, control of glycose, reduction of the risk of some types of cancer and of the symptoms of chronic constipation and hemorrhoids (Colonetti, 2012). I.e., the fruits of the species of Acrocomia, beside its use for oil extraction, due to the large quantity of mucilage present in the mesocarp can also be extracted and sold to different industrial segments. Furthermore, the process of demucilage, i.e., the extraction of mucilage from the plant tissue, can increase oil yield, as demonstrated by Speroni et al. (2015), who increased the efficiency of oil extraction by 30% after demucilage of flax seeds (Linum usitatissimum L.). 3.3.3 Starch The Lugol test was only positive for A. intumescens and one individual of A. aculeata. Starch in these species was observed in the parenchymatic cells of the mesocarp. The amyloplasts are grouped in spheres, what was also observed by Bonin et al. (2008) in samples of A. aculeata from another region of the state of São Paulo (Figure 8 d). Starch are natural polysaccharides, little soluble and of high molecular weight, formed by various sequences of amylose and amylopectin. Amylose is a linear polymer, and amylopectin is a well ramified macromolecule, spheric to elliptic (Salisbury & Ross, 1992). The shape of starch grains can be distinguished mainly by the quantity of amylose, since the higher the content of amylose in relation to amylopectin, more spheric are the starch grains (Bewley & Black, 1994). So, due to the spheric shape of the starch grains present in the studied species of Acrocomia, we infer that the quantities of amylose are higher, similar to the report by Silva and Potiguara (2009) who also found spheric starch grains in species of Oenocarpus (Arecaceae). This corroborates Tomlinson (1961) about the lack of morphological diversity of starch grains in Arecaceae, therefore it is not a useful character for taxonomic distinction in this botanical family. According to Montoya (2013) and Reis (2012), the accumulation of starch in fruits of A. aculeata happens during all development phases, after fecundation of the ovule. Nevertheless, after the 36th week post-anthesis there is a marked reduction of starch content and thereafter a linear increase in production and accumulation of oil, so presenting a relation between the degradation of starch and the synthesis of fatty acids after this phase (Montoya 2013), what is explained by the fact that the synthesis and storage of oil in plant tissues is directly related to the availability of stored polysaccharides, e.g. starch (França et al. 1999). Thus, we suggest that the fruits where starch was not detected would be in a more advanced phase, when the stored starch had already been converted into oil in the mesocarp. 3.3.4 Phenolic Compounds We observed cells with phenolic compounds in all analyzed species. According to Santos (2012), the phenolic compounds present in the mesocarp of A. aculeata occur inside the idioblasts. The largest quantity of phenolic idioblasts occurred among the analyzed samples of A. aculeata and A. totai (Table 3 and Figure 8 e, f). Phenolic compounds have antimicrobial activity and exert action against herbivory (Rocha et al., 2011b; Swain, 1959). Regarding economic potential, the phenolic compounds are the most abundant antioxidants in plants, because they can mitigate cumulative harms that can trigger several diseases (Rocha et al., 2013). Acrocomia aculeata stands out for its content of total phenolic compounds (Aragão, 2014; Rocha et al., 2013; Siqueira, 2012), supporting its potential use as fresh food or processed functional food. All detected compounds, beside oil, are liable to utilization by different industrial segments. 88 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 The description of the morphoanatomy of the mesocarp and the detection of the main biochemical compounds represent an important contribution upon fruits of Arecaceae, as there are not enough studies on structural organization of the vegetative organs and, moreover, of the reproductive organs. Ontogenetic studies of fruits of the other species of Acrocomia and of A. aculeata of different localities are needed to understand origin, function and organization of each tissue present in the fruits. Such studies could generate data which may could serve for taxonomic purposes, beside subsidize knowledge necessary for management for extraction of any fruit compound, for seed production and plant breeding. The histochemical tests, in addition to demonstrate that the high oil content present in other species than A. aculeata can also be utilized for extraction, evidenced the presence of other compounds, such as starch, phenolic compounds and mucilage that can contribute not only in nutrition as well as raw material for different industrial segments. 4. Conclusions The evaluation of biometry of fruits revealed the existence of morphological variation within and between populations and among the three species of Acrocomia aculeata, A. intumescens and A. totai, complementing data of plant morphology as well as confirming the hypothesis that the species are distinct. The morphoanatomy of the mesocarp of the analyzed species is similar. The mucilage in the mesocarp is responsible for water storage. Starch is stored until the fruit begins to ripen, when it is converted into oil. The oil present in the mesocarp occurs inside oleosomes. Acknowledgements To Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) for financial support. To PhD. Judas Tadeu de Medeiros Costa for guidance during the collections of Acrocomia intumescens in Recife, Pernambuco, Brazil. References Amorozo, M. C. M., & Gély, A. (1988). Uso de planas medicinais por caboclos do Baixo Amazonas, Barcarena, PA, Brasil. Boletim do Museu Paraense Emílio Goeldi, 4(1), 47-131. Alvarez, M., Costa, S. C., Utumi, H., Huber, A., Beck, R., & Fontana, J. D. (1992). The anionic glycan from the cactus Cereus peruvianus. Applied Biochemistry and Biotechnology, 34(1), 283-295. https://doi.org/10.1007/ BF02920552 Aragão, T. F. (2014). Macaúba (Acrocomia aculeata): caracterização centesimal, potencial antioxidante e compostos fenólicos da polpa e amêndoa. 51 f. Trabalho de Conclusão de Curso (Graduação em Tecnologia de Alimentos) – Universidade Tecnológica Federal do Paraná – Campus Campo Mourão, PR. Available at: http://repositorio.roca.utfpr.edu.br/jspui/handle/1/2299 Balick, M. J. (1984). Ethnobotany of palms in the neotropics. In G. T. Prance, & J. A. Kallunki (Eds.), Ethnobotany in the neotropics: Advances in Economic Botany. Bronx: The New York Botanical Garden. Berton, L. H. C. (2013). Diversidade, estimativas de parâmetros genéticos e seleção de genótipos elite de Macaúba (Acrocomia aculeata). 163 f. Tese (Pós-graduação em Agricultura Tropical e Subtropical) – Centro de Recursos Genéticos Vegetais, Instituto Agronômico de Campinas, São Paulo. Retrieved from http://www.iac.sp.gov.br/areadoinstituto/posgraduacao/dissertacoes/1270809.pdf Bewley, J. D., & Black, M. (1994). Seeds: physiology of development and germination (2 ed.). New York: Plenum Press. 445 pp. Bonin, M. P., Graner, E. M., Figueiredo, C. R. F., Almeida, C. V., & Almeida, M. (2008). Descrição Morfológica e Histológica de Fruto, Semente e Embrião de Macaúba (Acrocomia aculeata). In: Simpósio Internacional de iniciação Científica da USP (SIICUSP), Ribeirão Preto, SP. Retrieved from https://uspdigital.usp.br/siicusp/cdOnlineTrabalhoVisualizarResumo?numeroInscricaoTrabalho=4278&num eroEdicao=16 Bora, P. S., & Rocha, R. V. M. (2004). Macaiba palm: Fatty and amino acids composition of fruits. Ciência e Tecnologia de Alimentos, 4(3), 158-162. https://doi.org/10.1080/11358120409487755 Bran, C. (2013). ‘Coyoleras’ alistan vino para Semana Santa. In: La Nación Entretenimento. Ed. 27/03/2013. Sán José, Costa Rica: Grupo Nación S. A. Retrieved from http://www.nacion.com/ocio/artes/Coyoleras -alistanvino-Semana-Santa_0_1331866919.html 89 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 Cárdenas, A., Arguelles, W. M., & Goycoolea, F. (1998). On the posible rol of Opuntia ficus-indica: mucilage in lime mortar perfomance in the protection of historical buildings. Journal of the Professional Association for Cactus Development, Évora, 3. Carvalho, J. E. U., Nazaré, R. F. R., & Nascimento, W. M. O. (2003). Características físicas e físico-químicas de um tipo de bacuri (Platonia insignis Mart.) com rendimento industrial superior. Revista Brasileira de Fruticultura, 25, 326-328. https://doi.org/10.1590/S0100-29452003000200036 Colonetti, V. C. (2012). Caracterização da mucilagem do fruto e cladódio de Cereus hildmaniannus K. Schum. 83 f. Dissertação (Pós-Graduação em Engenharia Química) – Universidade Federal de Santa Catarina, Florianópolis. Retrieved from https://repositorio.ufsc.br/bitstream/handle/123456789/100836/313010.pdf? sequence=1&isAllowed=y Corrêa, M. P. (1984). Dicionário das plantas úteis do Brasil e das exóticas cultivadas. Rio de Janeiro: IBDF. v. 6. Fundação Centro Tecnológico de Minas Gerais (CETEC). (1983). Produção de combustíveis líquidos a partir de óleos vegetais. V.1. CETEC, Belo Horizonte, 151p. Ciconini, G., Favaro, S. P., Roscoe, R., Miranda, C. H. B., Tapeti, C. F., Miyahira, M. A. M., Bearari, L., Galvani, F., Borsato, A. V., Colnago, L. A., & Naka, M. H. (2013). Biometry and oil contents of Acrocomia aculeata fruits from the Cerrados and Pantanal biomes in Mato Grosso do Sul, Brazil. Industrial Crops and Products 45, 208–214. https://doi.org/10.1016/j.indcrop.2012.12.008 Conceição, L. D. H. C. S., Junqueira, N. T. V., Licurgo, F. M. S., Antoniassi, R., Wilhelm, A. E., & Braga, M. F. (2012). Teor de óleo em frutos de diferentes espécies de Macaubeira (Acrocomia spp.). In Congresso Brasileiro de Fruticultura, 22, Anais... Bento Gonçalves: Sociedade Brasileira de Fruticultura. Dôres, R. G. R. (2007). Análise morfológica e fitoquímica da fava d’anta (Dimorphandra mollis Benth.). Tese (Pós-Graduação em Fitotecnia) – Universidade Federal de Viçosa, MG. Retrieved from http://alexandria.cpd.ufv.br:8000/teses/fitotecnia/2007/200453f.pdf Dransfield, J., Uhl, N. W, Asmussen, C. B., Baker, W. J., Harley, M. M., & Lewis, C. E. (2008). Genera Palmarum – The Evolution and Classification of Palms. Royal Botanical Gardens, Kew: Kew Publishing. 732 p. Esau, K. (1977). Anatomy of Seed Plants. New York: John Wiley & Sons. Fanh, A. (1979). Secretory tissues in plants. San Francisco: Academic Press, 302p. França, L. F., Reber, G., Meireles, A., Machado, N., & Brunner, G. (1999). Supercritical extraction of carotenoids and lipids from buriti (Mauritia flexuosa), a fruit from the Amazon region. Journal of Supercritical Fluids, 14: 247–256. https://doi.org/10.1016/S0896-8446(98)00122-3 Gerlach, D. (1984). Botanische Mikrotechnik. Stuttgart: Georg Thieme Verlag. Hammer, Ø., Harper, D. A., & Ryan, P. D. (2001). PAST: Paleontological statistics software package for education and data analysis. Palaeontologia Electronica, 4, 1-99. Henderson, A., Galeano G., & Bernal, R. (1995). Field Guide to the Palms of the Americas (pp. 166-167). Princeton: Princeton University Press. Hernández, B. C. R., Hernández, J., Verduzco, J. E. G. A., Frier, J. P., Barrios, E. P., & Martínez, M. A. G. (2011). Importancia agroecológica del coyul (Acrocomia mexicana Karw. ex Mart.). Estudios Sociales, 21(41), 97113. Hiane, P. A., Filho, M. M. R., Ramos, M. I. L., & Macedo, M. L. R. (2005). Óleo da polpa e amêndoa de bocaiúva, Acrocomia aculeata (Jacq.) Lodd. ex Mart. Caracterização e composição em ácido graxos. Brazilian Journal of Food Technology, 8(3), 256-259. Ho, L. S., Nair, A., Yusof, H. M., & Kulaveerasingam, M. S. J. (2014). Morphometry of lipid bodies in embryo, kernel and mesocarp of Oil Palm: Its relationship to yield. American Journal of Plant Sciences, 5, 1163-1173. https://doi.org/10.4236/ajps.2014.59129 Horn, P. J., James, C. N., Gidda, S. K., Kilaru, A., Dyer, J. M., Mullen, J. B. O., & Chapman, K. D. (2013). Identification of a new class of lipid droplet-associated proteins in plants. Plant Physiology, 162, 1926–1936. https://doi.org/10.1104/pp.113.222455 Jensen, W. A. (1962). Botanical histochemistry. San Francisco: W.H. Freeman, 408p. Johansen, D. A. (1940). Plant microtechnique. New York: McGraw-Hill Book Company. 90 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 Lentz, D. L. (1990). Acrocomia mexicana: Palm of the Ancient Mesoamericas. Journal of Ethnobiology, 10(2), 183-194. Lima, J. L. S. (1994). Ornamental palms native to Northeastern Brazil and their geographic distribution. Acta Horticulturae - Ornamental Palms, I(360), 81-84. Lorenzi, H, Kahn, F., Noblick, L. R., & Ferreira, E. (2010). Flora Brasileira – Arecaceae (Palmeiras). Nova Odessa: Instituto Plantarum. 368 p. Manfio, C. E., Motoike, S. Y., Santos, C. E. M., Pimentel, L. D., Queiroz, V., & Sato, A.Y. (2011). Repetibilidade em características biométricas do fruto de macaúba. Ciência Rural, 41(1), 71-76. https://doi.org/10.1590/ S0103-84782011000100012 Montoya, S. G. (2013). Caracterização do desenvolvimento do fruto da palmeira macaúba. 62 f. Dissertação (PósGraduação em Fitotecnia) – Universidade Federal de Viçosa, MG. Available at: http://locus.ufv.br/handle/123456789/4614 Moraes, R. M. (2004). Flora de Palmeras de Bolívia. La Paz Plural Editores. 484p. Moura, R. C., Lopes, P. S. N., Brandão-Júnior, D. S., Gomes, J. G., & Pereira, M. B. (2010). Biometria de frutos e sementes de Butia capitata (Mart.) Beccari (Arecaceae), em vegetação natural no Norte de Minas Gerais, Brasil. Biota Neotropical, 10(2), 415-419. https://doi.org/10.1590/S1676-06032010000200040 O’Brien, T. P., Feder, N., & Mccully, M. E. (1964). Polychromatic staining of plant cell walls by toluidine blue O. Protoplasma, 59, 368-373. https://doi.org/10.1007/BF01248568 Pearse, A. G. E. (1960). Histochemistry theoretical and applied: preparative and optical technology (vol. 1, 4th ed.). Edinburgh: Churchil Livingston. 439 p. Plotkin, M. J., & Balick, M. J. (1984). Medicinal uses of South American palms. Journal of Ethnopharmacology, 10, 157-179. https://doi.org/10.1016/0378-8741(84)90001-1 Pott, E. B. (1986). Teores de minerais e proteína bruta em plantas forrageiras da parte alta de Corumbá, MS. Comunicado Técnico n.06/86. Embrapa: Centro de Pesquisa Agropecuária do Pantanal. 6 p. Proctor, G. R. (2005). Arecaceae (Palmae). In P. Acevedo-Rodríguez, & M. T. Strong (Eds.), Monocots and Gymnosperms of Puerto Rico and the Virgin Islands. Smithsonian Institution: Contributions of the United States National Herbarium (vol. 52, p. 415). Retrieved from http://botany.si.edu/Antilles/PRFlora/monocots/ vol52web.pdf Ramos, M. I. L., Ramos-Filho, M. M., Hiane, P. A., Braga-Neto, J. A., & Siqueira, E. M. A. (2008). Qualidade nutricional da polpa de bocaiúva Acrocomia aculeata (Jacq.) Lodd. Ciência e Tecnologia de Alimentos, 28(Supl.), 90-94. https://doi.org/10.1590/S0101-20612008000500015 Reis, S. B., Mercadante-Simões, M. O., & Ribeiro, L. M. (2012). Pericarp development in the macaw palm Acrocomia aculeata (Arecaceae). Rodriguésia, 63(3), 541-549. https://doi.org/10.1590/S2175-786020120 00300005 Rocha, M. S., Figueiredo, R. W., Araújo, M. A. M., & Moreira-Araújo, R. S. R. (2013). Caracterização físicoquímica e atividade antioxidante (in vitro) de frutos do Cerrado Piauiense. Revista Brasileira de Fruticultura, 35(4), 933-941. https://doi.org/10.1590/S0100-29452013000400003 Rocha, J. F., Pimentel, R. R., & Machado, S. R. (2011a). Estruturas secretoras de mucilagem em Hibiscus pernambucensis Arruda (Malvaceae): distribuição, caracterização morfoanatômica e histoquímica. Acta Botanica Brasilica, 25(4), 751-763. https://doi.org/10.1590/S0102-33062011000400003 Rocha, W. S., Lopes, E. M., Silva, D. B. Vieira, R. F., Silva, J. P., & Agostini-Costa, T. S. (2011b). Compostos fenólicos e taninos condensados em frutas nativas do Cerrado. Revista Brasileira de Fruticultura, 33(4), 1215-1221. https://doi.org/10.1590/S0100-29452011000400021 Rocha, J. F., Neves, L. J., & Pace, L.B. (2002). Estruturas secretoras em folhas de Hibiscus tiliaceus L. e Hibiscus pernambucensis Arruda. Revista da Universidade Rural do Rio de Janeiro - Série Ciências da Vida, 22(1), 43-55. Sáenz, C., Sepúlveda, E., & Matsuhiro, B. (2004). Opuntia spp. mucilage's: a functional component with industrial perspectives. Journal of Arid Environments, 57(3), 275-290. https://doi.org/10.1016/S0140-1963(03) 00106-X Salisbury, F. B., & Ross, C. W. (1992). Plant physiology (4th ed.). Belmont: Wadsworth. 682 p. 91 ijb.ccsenet.org International Journal of Biology Vol. 9, No. 3; 2017 Santos, H. C. M. (2012). Acrocomia aculeata (Jacq.) Lodd. ex Mart. (Arecaceae) no norte de Minas Gerais: Morfoanatomia de flores e aspectos da biologia reprodutiva. 92 f. Dissertação (Pós-Graduação em Ciências Agrárias) – Universidade Federal de Minas Gerais, Montes Claros. Retrieved from http://www.bibliotecadigital.ufmg.br/dspace/bitstream/handle/1843/NCAP-9V5JBB/hellen.pdf?sequence=1 Silva, J. M. (2012). Arqueologia Botânica dos Jardins de Burle Marx: A Praça de Casa Forte e a Praça Euclides da Cunha, Recife, PE. 125 f. Dissertação (Pós-graduação em Desenvolvimento Urbano – Universidade Federal do Pernambuco). Recife, PE. Retrieved from http://www.repositorio.ufpe.br/handle/123456789/ 3654?show=full Silva, R. J. F., & Potiguara, R. C. V. (2009). Substâncias ergásticas foliares de espécies amazônicas de Oenocarpus Mart. (Arecaceae): caracterização histoquímica e ultraestrutural. Acta Amazonica, 39(4), 793-798. https://doi.org/10.1590/S0044-59672009000400007 Silva, S. D. A., Casagrande-Jr., J. G., & Magnani, M. (2007). Sistema de Produção da Mamona. Sistemas de Produção, 11. Versão eletrônica. Retrieved from http://sistemasdeproducao.cnptia.embrapa.br/FontesHTML/ Mamona/SistemaProducaoMamona/introducao.htm Siqueira, P. B. (2012). Caracterização bioquímica e compostos bioativos de macaúba (Acrocomia aculeata (Jacq.) Lodd. ex Mart.). Tese (Pós-Graduação em Ciência de Alimentos) - Universidade Estadual de Campinas, Faculdade de Engenharia de Alimentos. Retrieved from http://www.bibliotecadigital.unicamp.br/ document/?code=000879554 Souza, L. A., Moscheta, I. S., & Mourão, K. S. M. (2012). Fruto. In B. Apezzato-da-Glória, & S. M. CarmelloGuerreiro (Eds.), Anatomia Vegetal (3th ed. rev. e ampl. Viçosa, MG: Ed. UFV, pp. 347-368). Speroni, C. S., Silva, L. P., Goulart, F. R., Lovatto, N. M., Alves, B. M., & Pretto, A. (2015). Benefícios da retirada de mucilagem da linhaça para o aprimoramento da extração do óleo. In: Anais da 25ª Jornada Acadêmica Integrada da Universidade Federal de Santa Maria. Retrieved from https://portal.ufsm.br/ jai2010/anais/trabalhos/trabalho_1041275777.htm Swain, T., & Hillis, W. E. (1959). The phenolic constituents of Prunus domestica L. The quantitative analysis of phenolic constituents. Journal of the Science of Food and Agriculture, 10, 63-68. https://doi.org/10.1002/jsfa.2740100110 The Plant List. (2013). Version 1.1. Retrieved from http://www.theplantlist.org/ Tomlinson, P. B. (1961). Anatomy of the monocotyledons-II. Palmae. New York: Oxford University Press. Vaughan, J. G. (1960). Structure of Acrocomia fruit. Nature, 188(4744), 81. https://doi.org/10.1038/188081a0 Copyrights Copyright for this article is retained by the author(s), with first publication rights granted to the journal. This is an open-access article distributed under the terms and conditions of the Creative Commons Attribution license (http://creativecommons.org/licenses/by/4.0/). 92