Spatial Distribution , Morphological Descriptors and Seed Biometry of Syagrus oleracea ( Mart . ) Becc . ( Arecaceae ) : An Important Brazilian Cerrado Palm

The Syagrus oleracea is adapted for dry regions, has used for food, ornamental palm and development of cosmetic. It occurs in impacted areas of Cerrado. The management of the species is important for traditional communities. Morphological descriptors, biometric pyrenes and spatial distribution of individuals are important for the species distinction, conservation, forest management and implantation of breeding programs. Thus, our objectives were to determine and correlate the main morphological characters of the palm tree, to evaluate the biometric of the pyrenes and the spatial distribution of the species. Neighbourhood Density Function (NDF) evaluated the spatial distribution in georeferenced individuals in four populations (Mirabela, Mato Verde, Rio Pardo de Minas and Novorizonte). The Novorizonte population showed an aggregate pattern in the first distance classes. The other populations had a random pattern. We evaluated 13 morphological descriptors in six populations (Mirabela, Mato Verde, Rio Pardo de Minas, Novorizonte, Varzelandia and São João da Ponte). The cluster analysis corroborates the results obtained by the multivariate analysis, which shows a greater distance of the SJP3 and SJP5 samples from the other accessions. The evaluated characteristics of the pyrenes biometry were: longitudinal diameter, equatorial diameter and the mass of the pyrenes. The highest mean longitudinal (22.17 mm) and equatorial diameter (38.89 mm) in addition to the mean mass (9.29 g) were observed in the Novorizonte population. The fruits of S. oleracea present an elongated shape. The study generated important information about the species that is still little studied, and has economic potential for product development.


Introduction
The Arecaceae family is present in tropical regions, and in Brazil, 39 genus and 119 palm species are found, distributed from humid environments, such as the Amazon rainforest, to xeric environments, such as the Caatinga and Cerrado (Cappelatti & Schmitt, 2015).Among the species of Brazilian, palm trees, Syagrus oleracea (Mart.)Becc.stands out for its ecological and economic importance.The species is popularly known as Gueroba, Guairoba, Jaguaroba, Catolé, Pati and Pati-Amargoso, has a solitary stem, superficially ringed, with an average height of 5 to 20 meters of 15 to 30 cm in diameter, and 15 to 20 sheets arranged spirally in the canopy.It has small flowers, established in clusters that emerge predominantly from May to August and fruits that ripen in the period from October to December (Lorenzi et al., 2010).
The fruits are elliptical, ovoid or round, yellowish green.They are smooth with 4.0 to 5.5 cm in length with thick mesocarp, meaty, sweet and fibrous.The average annual production is 2,000 kg/ha of fruit and can reach 4,000 kg/ha.The almond is rich in vegetable oil with contents of 35 to 38% (Lorenzi, 1998).The fruits are about 5 cm in length, have a sweet taste, and are consumed in nature by the communities (Lorenzi et al., 2004).
Coconut pulp is used for the production of liqueurs and syrups and oil extracted from the almond for hair, skin and for cooking nutrition (Amorim et al., 2005).
It is exploited in a disorderly way (palm heart extraction and fruit collection), and populations are declining mainly by extractivism, habitat loss and fragmentation (Batista et al., 2011).These factors may contribute to decreased fitness of the populations, compromise future generations of the species (Begon et al., 2006), and changes in the pattern of spatial distribution of individuals within populations (Wiegand et al., 2007).
Biometrics provide tools that differentiate species of the same genus in the field (Cruz et al., 2001;Freitas et al., 2009).The size and other characteristics that can be obtained through the study of biometrics contribute to a better understanding of seed dispersal and seedling establishment (Fenner, 1993).Biometry is also used for differentiation of pioneer and non-pioneer species in tropical forests (C.C. Baskin & J. M. Baskin, 1998).The biometry of fruits of the species S. oleracea is also an important instrument for the detection of genetic variability within populations of the same species and a relation with the environment and with genetic improvement (Macedo et al., 2009;Gonçalves et al., 2000).
Seeds grow until they reach the characteristic size of the species (Carvalho & Nakagawa, 2000), with the presence of individual variations within the same species due to genetic variability and environmental influence during development (Turnbull, 1997).Another important factor in the biometry of fruits and seeds is related to the selection of seeds for the use of the edible parts for sustainable use of the species (Chuba et al., 2008).Complementary to the biometry studies, the evaluation of morphological characters of the palm are important for research of genetic variance as subsidies for conservation and better of the species in the future.
Characteristics as a proportion of the pulp, endocarp and seed are basic information on the productive and economic potential of the fruits for use as a food resource or as raw material in the industry in general.
Other important ecological factors to be studied are the distribution patterns of individuals in space.Spatial patterns of species distribution are results of ecological processes and biotic and abiotic factors.The analysis of spatial distribution is an important tool for the understanding of ecological and genetic processes in populations and communities, in forest environments, and as strategies for the conservation and sustainable management of species (Silva et al., 2014).Thus, we sought to investigate the species Syagrus oleracea on the spatial distribution of individuals in natural populations, evaluation of the morphological characters of palm trees and the pyrenes biometry as preliminary subsidies for commercial planting and breeding programs.

Spatial Distribution
The spatial distribution analyze pattern of the S. oleracea palm were performed using the SpPack program 1.38, using the second-order neighbors density function (NDF) (Condit et al., 2000) spatial distribution pattern of the species, including all individuals.Sixty-two individuals were sampled in four locations in the Cerrado of Northern Minas Gerais, Brazil (Novorizonte, Mirabela, Mato Verde and Rio Pardo de Minas -Note 1).
Simulations were performed by distance classes (t) between 1 and 50 m, with intervals of 5 m for the total population to avoid the occurrence of jagged plot or dentin pattern (Wiegand and Moloney, 2004).Correction of edge effect was calculated, according to Goreaud and Pelissier (1999).Using the values obtained in the NDF (t) statistic, correlograms were constructed as a function of distance t and compared to confidence intervals (upper and lower), obtained from 499 Monte Carlo random simulations (alpha = 0.01).The individuals of S. oleracea were mapped on position in the x and y-axes, with the help of a compass and GPS device.

Morphological Characteristics
We selected 13 morphological descriptors to S. oleracea (Table 1) in 25 accessions (palm trees with 15 to 20 meters in height) of 5 populations (Novorizonte, Rio Pardo de Minas, Mirabela, Varzelandia and São João da Ponte), in the northern Cerrado of the State of Minas Gerais, Brazil -Note 1).
Table 1.Morphological descriptors used in the characterization of the morphology of catolé plants (S. oleracea) Analysis of variance and estimation of the average squares of each morphological characteristic evaluated was performed.Significance was verified by the F test.For the quantification of the phenotypic divergence between the different provenances, multivariate analyzes were performed and the distances of Mahalanobis as a measure of genetic similarity were estimated.Also analyzed were canonic variables and grouping of provenances by the Tocher optimization algorithm.The Euclidean distance was obtained by paired group UPGMA from the means of the accesses of the different origins for the morphological descriptors and the matrix of variances and residual covariance (Cruz, 2006).Consistency of nodes was obtained with 10,000 bootstraps (Jolliffe, 1973).
The multivariate analysis of variance averaged and dispersion matrices relative to provenances was obtained.
The associations between the morphological descriptors were analyzed by means of estimates of the coefficients of simple linear correlation between the accesses studied, using the Pearson method.The level of significance of the aforementioned values was calculated by the t-test (Steel & Torrie, 1960).All analyzes were performed using the PAST 3.21 software application (Hammer et al., 2018).

Pyrenes Biometrics Evaluation
The pyrenes were collected within a radius of 6 meters of the plant S. oleracea, after natural baroque dispersion, which were randomly collected 30 samples of the 30 plants in three different areas (Novorizonte, Mato Verde and Mirabela -Note 2).
The pyrenes were forwarded to the Laboratory of Bioprospecting and Genetic Resources of the University of Montes Claros, UNIMONTES.Measurements of the longitudinal length (CLF) and equatorial diameter (DEF) of the fruits were obtained using a digital caliper, and the weight with analytical balance.For all values obtained, the mean, minimum and maximum values, standard deviation and coefficient of variation were determined.In addition, the data were submitted to correlation analysis, calculating the Pearson correlation coefficient (r) and testing its significance with the t test, with the support of the Bioestat 5.3 program (Ayres et al., 2007).

Spatial Distribution
The NDF analysis showed a random distribution pattern for the S. oleracea species for most populations, except for the Novorizonte population, which showed an aggregate pattern in the first distance classes (Figure 1).In the biometrics analysis, the correlations between the variables were positive and significant, demonstrating that larger pyrenes also have greater mass.In addition, it was found that pyrenes with greater length have bigger diameter.
In view of these results, further studies should be developed to assess the impacts of anthropogenic processes on species and genetic consequences in these populations.In addition to studies aimed at genetic improvement of the species and sustainable exploitation.
Three statistical hypotheses were tested: (1) Complete spatial randomness (null hypothesis): NDF values within the range of confidence intervals; (2) Aggregate standard (alternative hypothesis 1): NDF values above the upper confidence interval; (3) Segregated spatial pattern (alternative hypothesis 2): NDF values below the lower confidence interval.
Abbreviation Morphological Descriptor Description NLL Number of live leaves Count all sheets completely open without considering the closed ones SL Sheet length Measurement of the beginning of the leaf, until the last leaflet NLRSL Number of leaflets on right side of leaf Leaflet count NLLSL Number of leaflets on left side of leaf Leaflet count CLD Central leaf diameter Evaluation in the average position of the sheet LCP Length of center pin Measurement of the leaflet from the base to the right side of the leaf DCL Diameter of the central leaflet Measure done in the central position of the leaflet on the right side of the leaf DCH Diameter of chest height Measurement of stem circumference FDS Final diameter of the leaf sheath Measurement of the final diameter of the leaf sheath DCP Diameter of center pin Measurement of central pin diameter SD0 Stem diameter at ground level Measurement of soil-level stipe H7A Height of seventh ring Height measurement of the seventh ring TKB7180 Thickness of the knot below the 7th ring at 180° of its smallest thickness Measurement Thickness of the node inferior to the 7th ring at 180° of its lowest soil level thickness Figure 1.
Rio Pardo de Minas and Novorizonte, and another group between Varzelândia, Mirabela and São João da Ponte.