Adjustment of Mathematical Equations to Determine the Area Leaf of <i>Cordia myxa</i>L.

The objective of this study was to obtain mathematical equations through the leaf dimensions to estimate the area leaf of Cordia myxa L. 392 leaves of plants were collected, located in the municipality of São Mateus, North of the State of Espírito Santo, Brazil, 300 of which were used to adjust the equations and 92 for validation. Of all the leaves, the largest length (L) and maximum width (W) were measured, product of multiplying the length with the width (LW) and the real leaf area (RLA). Models equation first degree linear, quadratic and power were fitted, where RLA was the dependent variable as a function of L, W and LW as an independent variable. All equations were validated according to appropriate criterion. Thus, the power model ELA = 0.84(LW)0.9749, based on the product of multiplication of length with width (LW) is the most suitable for estimating the leaf area of Cordia myxa L.

Each Epiphyte on Its Branch: A Comparative Study between Different Phorophytes

Epiphytes are plants that use the mechanical support provided by a host tree, called phorophytes, without emitting haustorial structures. Constituting an important component of the flora, playing an important role in the maintenance of ecosystems, such as water and nutrient cycling, in addition to providing resources, sometimes unique, such as food and shelter, for the canopy fauna. However, the epiphytic flora may show high beta diversity, even when compared with different phorophytes, possibly as a response to the dendromorphological characteristics of the phorophyte. Thus, this work aims to: 1) compare whether the species richness of epiphytes differs in trees with different morphological characteristics, and 2) compare species composition among three tree species. For this, 10 individuals of three tree species were selected: Guaria guidonia, Ficus sp., and Roystonea oleracea. In each individual, the number of species (richness) of vascular epiphytes was recorded and obtained from the species composition. To test differences in richness values between the three trees, we used analysis of variance (ANOVA) followed by Tukey’s test. To understand whether the epiphyte community formed separate groups according to the tree species used, we used the available non-metric multidimensional scaling method (NMDS). Thirty-four species of epiphytes were found in the 30 phorophytes surveyed. The three tree species showed significantly different richness, with the highest found in Guarea guidonea and the lowest in Roystonea oleraceae. The NMDS showed that epiphytes group the three tree species into distinct groups, although Ficus sp individuals present a transitional community between the two other species. Thus, the results suggest that the differences in the richness and composition of the epiphytic flora of the different phorophytes are influenced by their distinct morphological characteristics.

Where Are the Bromeliads? A Study on Different Trails in the Ecological Reserve of Guapiaçu, RJ

Bromeliaceae are important in ecological restoration, showing easy adaptation to different environments, and constantly interacting with each other through ecological relationships, whose effects may or may not benefit the species involved. The hypothesis tested whether the population density of Hohenbergia augusta is higher in areas at a more advanced successional stage (brown trail), since the species is typical of more structured forest environments, occurring especially in the lower strata of the forest. Six plots of 10 meters (6 × 10 m) were installed, parallel to the brown and yellow trails, and with a distance of 5 m from the edge. Plots were allocated alternately between the two sides of the trail, 10 meters apart from each other when on the same side. In each plot, all H. augusta (Vell.) E. Morren bromeliads were sampled, without a minimum inclusion criterion, provided they were epiphytic phorophytes. The logarithm of the value was used for data normalization and later, the data were tested in a student’s t-test. The study pointed out that the highest population density of H. augusta occurred in the brown trail because the area is in a more advanced successional stage.

What Do Seedlings Like? The Relationship between Seedling Richness and Abundance with Abiotic Factors

Natural regeneration is the interaction of natural processes to restore the forest ecosystem. Its dynamics are influenced by the intensity and extent of a series of abiotic and biotic factors, which may be intrinsic or extrinsic. Knowing the importance of establishing natural regeneration within forest ecosystems, this work aimed to evaluate whether litter depth and trail distance influenced seedling abundance and richness in a forest fragment undergoing natural restoration. The hypothesis tested in this research was that abiotic factors influence the natural regeneration of this forest since they are factors that are directly linked to seed germination and seedling establishment. 30 plots of 1 m2 were randomly analyzed within the forest located on the brown trail. A millimeter ruler was used to diagnose the litter depth and a measuring tape to measure the distance from the plot to the edge. In each plot the seedlings were morpho-specified and each morphospecies had the number of individuals counted. Linear regression tests were performed to assess the relationships between species richness and trail distance and litter depth. The same was done for species abundance. All results showed that there is no relationship pattern between any of the variables. Other factors also influence the regeneration of a forest, such as luminosity and seed bank. Furthermore, litter depth is related to the successional stage of the forest. It was concluded that the abiotic factors tested do not influence the regeneration of the study area.

Modeling of the Leaf Area of <i>Maytenus obtusifolia</i>Mart. from Scanned Images

The leaf has a vital role in the functions of the plant, being responsible for photosynthesis and gas exchange. Thus, the objective of this study was to fit a mathematical equation model to estimate the leaf area of Maytenus obtusifolia Mart. through the linear dimensions of the leaves. For that, six hundred and fifteen healthy leaves were collected from plants belonging to the Federal University of Espírito Santo, S&#227;o Mateus Campus, in the municipality of S&#227;o Mateus, located in the north of the State of Espírito Santo, Brazil. All leaves were digitized and the images processed using the ImageJ&#174;software, obtaining the measurements of the maximum length of the main midrib (L), the maximum width of the leaf blade (W) and the real leaf area (RLA) of each sheet. Subsequently, the product of length and width multiplication (LW) was also obtained. 500 sheets were randomly separated for the generation of models of mathematical equations and their respective coefficient of determination (R2), where RLA was used as dependent variable as function of L, W or LW as independent variable. Based on the models generated, a 115 leaf sample was used for validation, where the L, W and LW values of this sample were replaced in the adjusted equations, thus obtaining the estimated leaf area (ELA). A comparison of the means of RLA and ELA was performed by Student’s t test at 5% probability. We also calculated the mean absolute error (MAE), the root mean square error (RMSE) and the Willmott index (d). The best equation was defined by the following criteria: non-significant values of RLA and ELA averages, R2 and index d closest to unit, and MAE and RMSE values with greater proximity to zero. The quadratic model equation represented by ELA=0.18122798+0.72847767(LW)+0.00002789(LW)2 generated by multiplying the length with the width (LW) is the most suitable for the estimation of the leaf area of Maytenus obtusifolia Mart., in a fast, safe and non-destructive way.

Artificial Defoliation to Simulate Losses on Production of Bean (<i>Phaseolus vulgaris</i>L. cv. Goytacazes)

The reduction of foliar area can cause yield reduction in common bean crops. The objective of this work was to verify which is the effect of different defoliation levels realized in several development stages of common bean (Phaseolus vulgaris L. cv. Goytacazes) over yield, weight of 100 seeds and number of pods per plant. The experimental design was randomized blocks, in a split-plot arrangement with five replications. The plot corresponded to the five defoliation epochs (first trifoliate leaf, flowering, pods formation, pods filling, and dry pods). In each plot, the split plot was represented by the four defoliation levels (0%, 33%, 67% and 100%). It was observed a decrease of yield for all levels defoliation considering all development stages, except for dried pods. The highest decrease was detected for flowering and pods formation. Through the regression analysis got a greater reduction in yield with 100% defoliation made at 42 days after emergence. The evaluation parameter that showed better relation with yield was a number of pods per plant.

Fruit Mass of <i>Carica papaya</i>L. from Cultivars Aliança and THB from the Width and Length of the Fruit

Papaya (Carica papaya L.) is a typical plant with a tropical climate, but also grown in subtropical regions. Using mathematical models well-adjusted allows with good precision to estimate characteristics of interest. The objective was to adjust an equation that estimates the fruit mass for each cultivar of papaya, Aliança and THB, using only one measure, length or width. The experiment was conducted in the municipality of Linhares in the state of Espírito Santo, Brazil. Seedlings were planted on the same day, spaced 3.6 × 1.5 m and in rows side by side. Initially, the equations were modeled, they were linearized and then the covariance analysis was performed in order to verify the possibility of an equation that would serve both cultivars. As the covariance was significant, it was necessary to develop equations for each cultivar. To obtain the growth equations, 350 fruits of cultivar Aliança and 550 of THB were used. The validation was performed with 50 fruits of each. The characteristics evaluated were the largest width (W in mm), the longest fruit length (L, in mm) and the observed mass (OM in g). The equations that best fit were those of the power model that use width (W) as an independent variable.

Sample Dimension for Evaluating Characters of Yellow Mombin

The objective of this study was to determine the sample size needed to evaluate characters of mature fruits of yellow mombin (Spondias mombin L.). 100 fruits were evaluated from plants grown under a shading system. In the laboratory, these fruits were measured by the characters: longitudinal length (mm);equatorial diameter (mm);fruit mass (g);yield of pulp (%);total soluble solids—TSS (&#176;Brix);titratable acidity—TA (% citric acid) and ratio (TSS/TA), being calculated the measures of central tendency and dispersion, and verified normality. Next, the sample size for each character was determined. For experimental evaluation of cajámirim fruits, considering an accuracy of 10% around the mean, 40 fruits per treatment should be evaluated, considering a completely randomized experiment.