ABSTRACT Several abiotic factors, such as water availability, significantly affect the development of forest species found in the understory. This research aimed to evaluate morphophysiological characteristics in plants of Erythroxylum pauferrense submitted to different water regimes. The experiment was developed in a greenhouse at the Federal University of Paraíba, Campus II, Areia, Paraíba, Brazil. The experimental design was in randomized blocks, with five water treatments [100%, 80%, 60%, 40% and 20% of the pot capacity (PC)] and four replications. Growth attributes, morphofunctional aspects, gas exchange, chlorophyll fluorescence and chlorophyll indices were evaluated. The data were submitted for analysis of variance, and in cases of significance, polynomial regression analyses were performed. The plants of Erythroxylum pauferrense submitted to 100% and 80% water levels of the PC present greater development and morphophysiological performance. In comparison, the evaluated parameters were significantly reduced in the regime of greater water stress (20% of the PC). Thus, the water regime of 80% of PC is the most recommended for producing seedlings of Erythroxylum pauferrense, promoting greater growth and significant changes in morphofunctional aspects, gas exchange, chlorophyll fluorescence and chlorophyll indexes.

RESUMO Vários fatores abióticos, como a disponibilidade de água, afetam significativamente o desenvolvimento das espécies florestais encontradas no sub-bosque. Esta pesquisa teve como objetivo avaliar características morfofisiológicas em plantas de Erythroxylum pauferrense submetidas a diferentes regimes hídricos. O experimento foi desenvolvido em casa de vegetação na Universidade Federal da Paraíba, Campus II, Areia, Paraíba, Brasil. O delineamento experimental foi em blocos ao acaso, com cinco tratamentos hídricos [100%, 80%, 60%, 40% e 20% da capacidade do vaso (PC)] e quatro repetições. Foram avaliados atributos de crescimento, aspectos morfofuncionais, trocas gasosas, fluorescência da clorofila e índices de clorofila. Os dados foram submetidos à análise de variância e, nos casos de significância, análises de regressão polinomial. As plantas de Erythroxylum pauferrense submetidas a regimes hídricos de 100% e 80% da PC apresentam maior desenvolvimento e desempenho morfofisiológico. Em comparação, os parâmetros avaliados foram significativamente reduzidos no regime de maior estresse hídrico (20% da PC). Assim, o regime hídrico de 80% de PC é o mais recomendado para produção de mudas de Erythroxylum pauferrense, promovendo maior crescimento e alterações significativas nos aspectos morfofuncionais, trocas gasosas, fluorescência da clorofila e índices de clorofila.

ABSTRACT Basil (Ocimum gratissimum - Lamiaceae), is a sub-shrub plant species with great economic importance for several regions, and studies on its growth, physiology, and reproduction become needed. The aimed research was to obtain a regression equation to estimate leaf area of O. gratissimum. 250 basil leaves were collected and the linear dimensions (length and width) and real leaf area of each leaf were measured. From these data, the products between length and width, length and length were calculated. Equations were obtained using regression models: linear, linear without intercept, quadratic, cubic, power, and exponential. The best equation was selected based on determination coefficient, Pearson’s correlation coefficient, Willmott’s agreement index and CS index, Akaike information criterion, mean absolute error and root mean square error. All equations proposed using the product between length and width (LW) can be used to predict the leaf area of O. gratissimum. However, the equation LA=0.54*LW1.03 (power model) is the most recommended to estimate the leaf area of this species.

ABSTRACT Ocimum basilicum L. (basil) is an annual herb belonging to the Lamiaceae family that has economic importance for many regions around the world. Thus, ecophysiological studies are needed to assess this species growth and dispersal. This work aimed to obtain equations from regression models that meaningfully estimate the leaf area of basil cultivars using linear dimensions of leaves. For this purpose, 300 leaves from 'Italiano Roxo' and 500 leaves from 'Folha Fina' cultivar were collected from plants cultivated in a greenhouse. Then, the length, width, and leaf area of each leaf were measured, and product of length by width were calculated. The equations were adjusted using the simple linear, linear without intercept, quadratic, cubic, power, and exponential regression models. Criteria for selecting the best equations were highest determination coefficient and Willmott's agreement index, lowest Akaike information criterion and root mean square error, and BIAS index closest to zero. All the equations fitted using the product of length by width (L.W) can estimate the leaf area of basil cultivars. Thus, basil leaf area can be estimated through a non-destructive method using linear dimensions of leaves. However, the equation ŷ = 0.8175*LW0.9307 is the most suitable for 'Italiano Roxo' and ŷ = 0.6335*LW for 'Folha Fina'.

RESUMO A luz solar influencia diretamente no desenvolvimento das espécies florestais, afetando os atributos de crescimento e fisiologia das plantas. Dentre essas espécies, Erythroxylum pauferrense Plowman é considerada uma espécie rara, pois sua distribuição é restrita apenas ao estado da Paraíba. Diante disso, são necessários estudos que busquem avaliar a adaptação, desenvolvimento e propagação da espécie em diferentes condições ambientais. Este trabalho teve como objetivo avaliar os aspectos morfofisiológicos de mudas de Erythroxylum pauferrense submetidas a diferentes níveis de sombreamento. O experimento foi conduzido em casa de vegetação, em delineamento inteiramente casualizado, com cinco tratamentos (0, 30, 50, 70 e 90% de sombreamento) e oito repetições. Foram avaliadas as características de crescimento, atributos morfofuncionais, trocas gasosas, fluorescência da clorofila (Chl) a e teor de Chl. Os dados foram submetidos à análise de variância seguida de análise de regressão polinomial. Os resultados mostraram que as plantas cultivadas sob 30 a 50% de sombreamento apresentaram maior altura da planta, diâmetro do caule, taxa de crescimento absoluto para altura da planta, massa seca da folha, massa seca do caule, massa seca total, índice de qualidade de Dickson, área foliar e índice de área foliar, bem como a taxa de assimilação líquida de CO2, condutância estomática, transpiração, eficiência instantânea do uso da água e conteúdo de Chl a, b e a+b. Portanto, níveis de 30 a 50% de sombreamento são os mais recomendados para a produção de mudas de Erythroxylum pauferrense. Recomenda-se o uso de Erythroxylum pauferrense para reflorestar o sub-bosque em áreas perturbadas nos Brejos de Altitude e a produção em larga escala de mudas em níveis de 30 a 50% de sombreamento.

ABSTRACT Sunlight directly influences on the development of forest species by affecting the attributes of plant growth and physiology. Among these species, Erythroxylum pauferrense Plowman is considered a rare species, as its distribution is restricted only to the state of Paraíba. Therefore, studies are needed that seek to evaluate the adaptation, development and propagation of the species under different environmental conditions. This study aimed to evaluate morphophysiological aspects of Erythroxylum pauferrense seedlings submitted to different levels of shading. The experiment was carried out under greenhouse condition in a completely randomized design with five treatments (0, 30, 50, 70, and 90% shading) and eight replicates. Growth characteristics, morphofunctional attributes, gas exchange, chlorophyll (Chl) a fluorescence, and Chl content were evaluated. Data were submitted to analysis of variance followed by polynomial regression analysis. Results showed that plants grown under 30 to 50% shading showed higher plant height, stem diameter, absolute growth rate for plant height, leaf dry mass, stem dry mass, total dry mass, Dickson’s quality index, leaf area, and leaf area index, as well as net assimilation rate of CO2, stomatal conductance, transpiration, instantaneous water use efficiency, and Chl a, b, and a+b contents. Therefore, levels from 30 to 50% shading are the most recommended for the production of Erythroxylum pauferrense seedlings. We recommend using Erythroxylum pauferrense to reforest the understory in disturbed areas in Brejos de Altitude and large-scale production of seedlings under intermediate levels of shading.

Abstract: Erythroxylum pauferrense Plowman is an understory species native to Brazil, with great importance in the conservation of genetic resources and is used as a food source for animals in the regions where the species occurs. The species is currently listed in category EN (endangered). The objective of this work was to evaluate the effect of different substrates on the emergence and initial growth of E. pauferrense. The experiment was carried out in a protected environment, belonging to the Plant Ecology Laboratory of the Federal University of Paraíba, Areia-PB, Brazil. The substrates used were: sand; sand + vermiculite in the proportion of 1:1, 3:1 and 1:3; vegetal land; vegetal land + sand in the proportion of 1:1, 3:1 and 1:3; vegetal land + vermiculite in the proportion of 1:1, 3:1 and 1:3; vermiculite; Bioplant®; and Bioplant® + sand in a ratio of 1:1, 3:1 and 1:3. The experimental design was completely randomized, with 16 treatments (substrates) and four replications of 25 seeds. The percentage of emergence, first count, speed index, mean time, mean speed and relative emergency frequency were evaluated. The vermiculite substrate provided the best results for carrying out the emergence and vigor tests of E. pauferrense seedlings, being the most suitable substrate to initial growth seedlings of the species.

Abstract Climatic variation throughout the day influences the ecophysiological performance of plants at different growth stages and phases. Therefore, this work aimed to evaluate the effect of climatic variation on ecophysiological aspects of T. roseoalba and H. heptaphyllus at different hours of the day and indicate the ideal time for measuring ecophysiological variables in these species. The research was carried out in a greenhouse at the forest nursery of the Federal University of Paraíba, Campus II, in the municipality of Areia, Paraíba state, Northeastern Brazil. The experimental design was completely randomized, consisting of 10 evaluation times throughout the day (from 8 am to 5 pm), with 1 h hour interval between each evaluation. Temperature and air relative humidity inside and outside the greenhouse were evaluated to understand the effect on gas exchange (net assimilation rate of CO2, stomatal conductance, transpiration rate, internal concentration of CO2, and vapor-pressure deficit) and chlorophyll a fluorescence (initial, maximum, and variable fluorescence, photochemical quenching, and electron transport rate). Data were submitted to canonical correlation analysis and principal component analysis to verify the relationship between climatic and ecophysiological variables. For both species, higher correlation was found between internal and external relative humidity with all the ecophysiological variables analyzed, except for initial fluorescence. Thus, climatic factors influenced the photosynthetic performance of T. roseoalba and H. heptaphyllus plants, and 8 am to 9 am is indicated for carrying out ecophysiological evaluations in both species.

ABSTRACT The determination of leaf area is fundamental for studies related to plant growth and physiology. Thus, non-destructive methods allow an accurate estimate of the leaf area through linear dimensions of the leaves. The research objective was to construct allometric equations to estimate the leaflet area of peanut cultivars. Then, 2,605 leaflets were collected from six peanut cultivars (IAC Caiapó, IAC 8112, Runner IAC 886, BRS Havana, BRS 151 L7, and IAC Tatuí), with more than 400 leaflets sampled for each cultivar. We measured the length, width, product between length and width, and leaflet area. Linear and non-linear models (linear, linear without intercept, power, and exponential) were built, and the best equation was chosen using the statistical criteria: highest coefficient of determination (R2), Pearson’s linear correlation coefficient (r), Willmott’s agreement index (d), lowest Akaike information criterion (AIC), and root mean square of the error (RMSE). It was found that the models that used the product between length and width were the most suitable for estimating the leaflet area of peanut cultivars. Given the little intraspecific morphological variability, it was possible to group the cultivars, and model y ^ = 0.875 * LW0.929 was indicated to estimate the peanut leaflet area accurately, regardless of the cultivar.

ABSTRACT The sesame crop has great economic potential due to the various possibilities of exploitation, however, there is a lack of information about the chemical control of weeds in the crop, mainly about the application of herbicides in pre-emergence. Therefore, the objective of this study was to evaluate the economic viability and efficacy of herbicides applied in pre-emergence for the control of weeds in the sesame crop. The experimental design was in randomized blocks, with four replications. The treatments consisted of seven herbicides (diuron, flumioxazin, oxadiazon, oxyfluorfen, metribuzin, linuron, and S-metolachlor) and a mixture (metribuzin + oxyfluorfen) applied in pre-emergence. The two control treatments were weeded and nonweeded plots. The variables evaluated were percentage of control of the weed community, grain yield, gross and net income, rate of return, and profitability index. The highest productivity value was for weeding, followed by the herbicides diuron and flumioxazin, with 2,000.44 kg ha-1, 1,957.35 kg ha-1;, and 1,933.13 kg ha-1, respectively. The herbicides diuron and flumioxazin obtained the highest net income, in the amounts of R$ 7,831.26 and R$ 7,762.85, respectively. The diuron and flumioxazin applied in pre-emergence showed more than 80% in the control of weeds in the sesame crop, showing efficiency in the control. The use of herbicides applied in pre-emergence to control weeds, mainly diuron and flumioxazin, is as efficient as mechanical control, demonstrating the potential for use and economic viability in relation to mechanical control, which presents a high cost/benefit ratio.

RESUMO A cultura do gergelim apresenta grande potencial econômico por conta das diversas possibilidades de exploração, contudo há carências de informações a respeito do controle químico de plantas daninhas na cultura, principalmente sobre a aplicação de herbicidas em pré-emergência. Sendo assim, o objetivo deste estudo foi avaliar a viabilidade econômica e a eficácia de herbicidas aplicados em pré-emergência para o controle de plantas daninhas na cultura do gergelim. O delineamento experimental foi em blocos casualizados, com quatro repetições. Os tratamentos foram constituídos de sete herbicidas (diuron, flumioxazin, oxadiazon, oxyfluorfen, metribuzin, linuron e S-metolachor) e uma mistura (metribuzin + oxyfluorfen) aplicados em préemergência. Os dois tratamentos testemunhas foram as parcelas capinadas e não capinadas. As variáveis avaliadas foram porcentagem de controle da comunidade infestante, produtividade de grãos, rendas bruta e líquida, taxa de retorno e índice lucratividade. O maior valor de produtividade foi para o tratamento capinado, seguido dos herbicidas diuron e flumioxazin, com 2.000,44 kg ha-1, 1.957,35 kg ha-1 e 1.933,13 kg ha-1, respectivamente. Os herbicidas diuron e flumiozaxin obtiveram as maiores rendas líquidas, nos montantes de R$ 7.831,26 e R$ 7.762,85, respectivamente. O diuron e flumioxazin aplicados em pré-emergência apresentaram mais de 80% no controle de plantas daninhas na cultura do gergelim, demostrando eficiência no controle. O uso de herbicidas aplicados em pré-emergência para o controle de plantas daninhas, principalmente o diuron e flumioxazin, é tão eficiente quanto o controle mecânico, demonstrando potencial de uso e viabilidade econômica em relação ao controle mecânico que apresenta custo/benefício elevado.

Abstract: Background and Aims: Determining the leaf area is essential for studies on growth, propagation, and ecophysiology of forest species. Developing quick, practical, and accurate methods is needed to estimate leaf area without destroying leaves. Therefore, this research aimed to obtain an equation from regression models that meaningfully estimate the leaf area of Erythroxylum pauferrense using linear dimensions of its leaf blades. Methods: For this purpose, 1200 leaves were randomly collected from different plants in the Mata do Pau-Ferro, a state park located in Areia city, Paraíba state, Brazil. Equations were fitted from simple linear, linear without intercept, quadratic, cubic, power, and exponential regression models. Next, the best equation was selected by checking the following assumptions: higher determination coefficient (R²) and Willmott's index (d), lower Akaike information criterion (AIC) and root mean square error (RMSE), as well as the BIAS index closest to zero. Key results: Based on the criteria used, all equations fitted using the product of length by width (L.W) can estimate the leaf area of E. pauferrense. Conclusions: The equation ŷ=0.6740*LW from the linear model without intercept significantly estimates the leaf area of E. pauferrense in a quick and practical way (R²=0.9960; d=0.9953; AIC=1231.61; RMSE=0.4255; BIAS=-0.0130).

Resumen: Antecedentes y Objetivos: La determinación del área foliar es esencial para los estudios sobre crecimiento, propagación y ecofisiología de especies forestales. Es necesario desarrollar métodos rápidos, prácticos y precisos para estimar el área de la hoja sin destruir las hojas. Por lo tanto, esta investigación tuvo como objetivo obtener una ecuación a partir de modelos de regresión que estimen significativamente el área foliar de Erythroxylum pauferrense, utilizando dimensiones lineales de sus láminas foliares. Métodos: Para este propósito, se recolectaron al azar 1200 hojas de diferentes plantas en Mata do Pau-Ferro, un parque estatal ubicado en la ciudad de Areia, estado de Paraíba, Brasil. Las ecuaciones se ajustaron a partir de modelos de regresión lineal simple, lineal sin intercepción, cuadrática, cúbica, de potencia y exponencial. Luego, se seleccionó la mejor ecuación verificando los siguientes supuestos: coeficiente de determinación más alto (R²) e índice de Willmott (d), criterio de información de Akaike más bajo (AIC) y error cuadrático medio (RMSE), así como el índice BIAS más cercano a cero. Resultados clave: Basado en los criterios utilizados, todas las ecuaciones ajustadas usando el producto de largo por ancho (L.W) pueden estimar el área foliar de E. pauferrense. Conclusiones: La ecuación ŷ=0.6740*LW del modelo lineal sin intercepción estima significativamente el área foliar de E. pauferrense de una manera rápida y práctica (R²=0.9960; d=0.9953; AIC=1231.61; RMSE=0.4255; BIAS=-0.0130).

Abstract Estimating leaf area is essential to evaluate vegetal growth. Our study sought to obtain statistical models to allow the leaf area estimation of Palicourea racemosa, considering its length (L) and width (W). For such purpose, we collected 200 leaves of this species in the State Park Mata do Pau-Ferro, in the municipality of Areia, Paraíba, Northeast of Brazil. The regression models used were: linear, linear without intercept, power and exponential. The choice of the best equation was based on the values of the coefficient of determination (R2), root mean square error (RMSE), Akaike information criterion (AIC), Willmott concordance index (d) and BIAS ratio. All linear and power models may be used to measure the P. racemosa leaf area; however, the power model LA = 0 . 609 * ( L . W ) 0 . 995 is the most recommended to estimate this species’ leaf area.