ResumoO objetivo do trabalho foi avaliar a atividade como antifúngico, antibacteriano e indutor da produção de fitoalexinas dos hidrolatos de Helietta apiculata (canela-de-veado) (HA), Conyza canadensis (buva) (CC) e Cymbopogon nardus (citronela) (CN) nas concentrações de 1, 5, 10, 15, 20 e 25%, buscando seu uso no controle alternativo de doenças em plantas. Para o ensaio de fitoalexinas foram utilizados mesocótilos estiolados de sorgo. Para o efeito antibacteriano foi avaliado o crescimento da bactéria Xanthomonas campestris pv. campestris em meio caldo nutriente suplementado com os tratamentos, tendo como testemunha mistura de antibióticos (22,5 mg/L de oxitetraciclina + 225 mg/L de estreptomicina). O efeito antifúngico foi avaliado através da mensuração do crescimento vegetativo, esporulação, germinação de esporos e desenvolvimento do tubo germinativo de Alternaria brassicae, sendo o fungicida azoxystrobin (0,08 g i.a./L) usado como controle. Foi observado acréscimo na síntese de fitoalexinas com o aumento na concentração dos hidrolatos, sendo o melhor resultado obtido com CN, o qual promoveu aumento de cerca de 4,3 vezes mais, seguido de HA (2,5 vezes) e CC (2,1 vezes), em relação a testemunha água. Resultados semelhantes foram obtidos para crescimento bacteriano com os seguintes resultados de inibição (em %) no desenvolvimento da bactéria: CN: 29,8, HA: 14,9, CC: 14,6 e antibióticos: 97,7. Com relação à ação antifúngica foi observada inibição do desenvolvimento dos tubos germinativos, sendo que os hidrolatos de CC e HA inibiram 69,2 e 56,2%, respectivamente, resultado semelhante ao fungicida. O hidrolato de CN não apresentou efeito antifúngico. Estes resultados indicam a presença de compostos indutores de fitoalexinas, antibacterianos e antifúngicos nesses hidrolatos, porém em baixas concentrações.

The aim of this study was to evaluate the efficiency of the adjustment of mathematical models for determining Bauhinia monandra leaf area using the length and/or width of the leaves as independent variables. Leaves from plants with three years were used to the estimative of equations in linear, quadratic and potential models. The validation from the estimated leaf area as a function of the observed leaf area showed that the linear model based on the product of length and width of the largest leaf surface is the model that best fits. However, the leaf area determination can be represented by using only the length or width of the leaves with little loss of accuracy. A representation that better estimates Bauhinia monandra leaf area with easy application is the potential model in which xi represents the length of one of the symmetrical leaf lobes.

The objective of this study was to determine mathematical equations that estimate the leaf area of jackfruit (Artocarpus heterophyllus) in an easy and non-destructive way based on linear dimensions. In this way, 300 leaves of different sizes and in good sanitary condition of adult plants were collected at the Federal Institute of Espírito Santo, Campus Itapina, located in Colatina, municipality north of the State of Espírito Santo, Brazil. Were measured The length (L) along the midrib and the maximum leaf width (W), observed leaf area (OLA), besides the product of the multiplication of length with width (LW), length with length (LL) and width with width (WW). The models of linear equations of first degree, quadratic and power and their respective R2 were adjusted using OLA as dependent variable in function of L, W and LW, LL and WW as independent variable. The data were validated and the estimated leaf area (ELA) was obtained. The means of ELA and OLA were compared by Student’s t test (5% probability) and were evaluated by the mean absolute error (MAE) and root mean square error (RMSE) criteria. The choice of the best model was based on non-significant comparative values of ELA and OLA, in addition to the closest values of zero of EAM and RQME. The jackfruit leaf area estimate can be determined quickly, accurately and non-destructively by the linear first-order model with LW as the independent variable by equation ELA = 1.07451 + 0.71181(LW).

The objective of the present study was to test and establish mathematical models to estimate the leaf area of Garcinia brasiliensis Mart. through linear dimensions of the length, width and product of both measurements. In this way, 500 leaves of trees with age between 4 and 6 years were collected from all the cardinal points of the plant in the municipality of São Mateus, North of the State of Espírito Santo, Brazil. The length (L) along the main midrib, the maximum width (W), the product of the length with the width (LW) and the observed leaf area (OLA) were obtained for all leaves. From these measurements were adjusted linear equations of first degree, quadratic and power, in which OLA was used as dependent variable as function of L, W and LW as independent variable. For the validation, the values of L, W and LW of 100 random leaves were substituted in the equations generated in the modeling, thus obtaining the estimated leaf area (ELA). The values of the means of ELA and OLA were tested by Student’s t test 5% of probability. The mean absolute error (MAE), root mean square error (RMSE) and Willmott’s index d for all proposed models were also determined. The choice of the best model was based on the non significant values in the comparison of the means of ELA and OLA, values of MAE and RMSE closer to zero and value of the index d and coefficient of determination (R2) close to unity. The equation that best estimates leaf area of Garcinia brasiliensis Mart. in a way non-destructive is the power model represented by por ELA = 0.7470(LW)0.9842 and R2 = 0.9949.

The objective of this study was to determine a suitable plot size for field experiments with papaya genotypes. Two experiments were carried out using a randomized complete block design with 11 and 12 papaya genotypes, respectively. In both experiments, plots consisted of one row, with 10 plants each. Spacing between rows was 3.5 m, with 1.5 m between plants. The characteristic evaluated was fruit production in t ha -1 in first year of cultivation, and the basic unit used was one plant. Suitable plot size was estimated using Lin and Binns, and Hatheway's methods. These methods are complementary and should be used together in the determination of the optimum plot size. The results of these tests showed that the optimum plot size for the evaluation of yield in papaya was four plants by plot with four replications each assuming 30% of the precision for establishing differences among the means of two genotypes.

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, São Mateus Campus, in the municipality of São Mateus, located in the north of the State of Espírito Santo, Brazil. All leaves were digitized and the images processed using the ImageJ® 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 (R 2), 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, R 2 and index d closest to unit, and MAE and RMSE values with greater proximity to zero. The quadratic model equation

The present study had as objective to determine mathematical equations to estimate the leaf area of pear cv. 'Triunfo' using linear dimensions of the leaves. For that, 300 healthy leaves of different sizes from each quadrant of plants from the small farm of Boa Vista located in the city of Montanha, at the northern side of the State of Espírito Santo, Brazil were used. The length (L) along the main vein was measured, along with the maximum width (W) of the leaf blade and observed leaf area (OLA), in addition to the product of the length and width (LW) of each leaf. From these measurements models of linear equations of first degree, quadratic and power were adjusted and their respective R 2, using OLA as dependent variable and L, W and LW as independent variable. Based on the proposed equations, the data were validated obtaining the estimated leaf area (ELA). The mean of the ELA and OLA were compared by Student t test 5% probability. The mean error (E), the mean absolute error (MAE) and the root mean squared error (RMSE) was also used as validation criterion. The best equation model was defined based on the non-significant values from the comparison of means of ELA and OLA, E, MAE and RMSE values closer to zero and highest R 2 . The leaf area of pear cv. 'Triunfo' can be estimated by the equation ELA = -0.432338 + 0.712862(LW) non-destructively and with a high degree of precision.

The objective of this study was to determine the best equation for estimating the leaf area of ​​Acacia mangium Willd. from the linear dimensions of the leaflets of non-destructive form. For this, 476 leaflets of plants belonging to Lajeado farm were collected in the municipality of Ecoporanga, in the north of the State of Espírito Santo, Brazil. From each leaflet was determined the length (L) along the main midrib, the largest width (W), the product of the multiplication between the length and the width (LW) the observed leaf area (OLA). For the modeling, we used 382 leaflets in which OLA was the dependent variable in function of L, W or LW as independent variable, being adjusted the linear models of first degree, quadratic and power. For the validation, the values ​​of L, W and LW of 94 leaflets were replaced in the equations obtained in the modeling thus obtaining the estimated leaf area (ELA). The means of ELA and OLA were compared by Student's t test at 5% probability. . It was also determined the mean absolute error (MAE), the root mean square error (RMSE) and Willmott's index d. In order to select the best equation, the following criteria were used: : not significant of the comparison of the means of ELA and OLA, values ​​of MAE and RMSE with closer to zero and index d closer to one. The power model equation represented by is the most adequate to predict the leaf area of ​​Acacia mangium Willd. quickly and non-destructively.