Abstract Physiological and yield evaluation of perennial forage plants grown in intercropping in the semiarid region is indispensable in the search for higher efficiency of the agricultural and livestock production systems. In this context, an experiment was carried out at the Experimental Station of the National Institute of the Semiarid Region - INSA, in the municipality of Campina Grande, Paraíba, Brazil, to evaluate the physiological efficiency and yield of prickly pear and gliricidia in intercropping. Treatments were distributed in randomized blocks, with six replicates, being represented by four spacings between gliricidia plants: S1 (1.0 m), S2 (1.5 m), S3 (2.0 m) and S4 (3.0 m) x 2.30 m between rows. Prickly pear was planted in double rows of 1.5 m x 0.8 m x 0.5 m. The analyzed variables were initial, maximum and variable fluorescence chlorophyll a, variable/initial fluorescence ratio, potential quantum yield and the fresh matter yield of both crops. Density planting of gliricidia up to 4,348 plants ha-1 increases its photochemical efficiency and yield, but reduces light energy capture by prickly pear in intercropping, whereas its yield is not influenced by cultivation density. Regardless of gliricidia density, prickly pear yield was not influenced.

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 Pomegranate is a fruit with potential for exploitation in the Brazilian Northeast as medicine and food. However, the qualitative and quantitative scarcity of water resources is common in this region, requiring the use of water with high salt contents in irrigated agriculture. The adoption of strategies to reduce the harmful effects of salt stress in plants is therefore necessary, and foliar nitrogen (N) fertilization is a promising alternative. The objective of the work, therefore, was to evaluate the photochemical and phytomass aspects of pomegranate seedlings grown under irrigation water salinity and foliar nitrogen fertilization. The experiment was performed in a randomized block design, in an incomplete factorial scheme, with five levels of electrical conductivity of irrigation water - ECw (0.50, 1.15, 2.75, 4.35 and 5.00 dS m-1) and five nitrogen doses - N (0.0, 0.33, 1.15, 1.97 and 2.30 g L-1), totaling nine combinations, generated by the Central Composite Design, with four repetitions and two plants per repetition. Foliar N application at a dose of 1.37 g L-1 increased the production of leaf and root dry phytomass at 90 days after emergence. Salt stress reduced the photochemical activity and phytomass production of pomegranate seedlings, while there was a stimulus by increasing N application up to 2.3 g L-1.

Resumo A romã é uma fruteira com potencial de exploração no Nordeste brasileiro com potencial de uso como composto medicinal e na alimentação. Porém, a escassez qualitativa e quantitativa dos recursos hídricos é comum nesta região, sendo necessário o uso de águas com elevados teores de sais na agricultura irrigada. Assim, é necessário a adoção de estratégias para reduzir os efeitos deletérios do estresse salino sobre as plantas, sendo a adubação foliar nitrogenada uma alternativa promissora. Assim, o objetivo do trabalho foi avaliar os aspectos fotoquímicos e as fitomassas da romãzeira em função da salinidade da água de irrigação e adubação foliar de nitrogênio (N). O experimento foi realizado em delineamento experimental de blocos casualizados, em arranjo fatorial incompleto, com cinco níveis de condutividade elétrica da água - CEa (0,50; 1,15; 2,75; 4,35 e 5,00 dS m-1) e cinco doses de nitrogênio - N (0,0; 0,33; 1,15; 1,97 e 2,30 g L-1), totalizando nove combinações, gerados pela matrix Composto Central de Box, com quatro repetições e duas plantas por repetição. A aplicação foliar de N na dose de 1,37 g L-1, aumentou a produção de fitomassa seca de folhas e da raiz, aos 90 dias após a emergência. O estresse salino reduziu a atividade fotoquímica e a produção de fitomassa das plantas de romã, enquanto houve um estimulo pela aplicação crescente de N até 2,3 g L-1.

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.

Resumen En la región semiárida de Brasil, las sales se encuentran en el agua utilizada en el riego. El objetivo de fue analizar la influencia de la fertilización foliar con nitrógeno como mitigador del estrés salino en plántulas de maracuyá. El diseño fue bloques al azar, con los tratamientos generados a partir de la matriz Compuesta Central de Caja, con cinco conductividades eléctricas del agua de riego (ECr) (0.50; 0.98; 2.15; 3.32; 3.80 dS m-1) y cinco dosis de fertilización nitrogenada foliar (0.0; 0.30; 1.15; 1.97; 2.30 g L-1), con cuatro repeticiones. Se evaluó el crecimiento y pigmentos fotossintéticos. La aplicación de dosis de nitrógeno atenuó el efecto de la salinidad sobre aspectos morfofisiológicos de plántulas de maracuyá. El aumento de la salinidad del agua provocó efectos negativos en las características de crecimiento y pigmentos fotosintéticos.

Abstract In the semiarid region of Brazil, salts found in water used in irrigation. The objective of was to analyze the influence of foliar fertilization with nitrogen as a mitigation of the salt stress of passion fruit seedlings. The design was randomized blocks, with the treatments generated from the Box’s Central Composite matrix, with five electrical conductivities of irrigation water (ECw) (0.50; 0.98; 2.15; 3.32; 3.80 dS m-1) and five doses of foliar nitrogen fertilization (0.0; 0.30; 1.15; 1.97; 2.30 g L-1), with four replicates. The growth and photosynthetic pigments were evaluated Application of nitrogen doses attenuated the effect of salinity on morphophysiological aspects of passion fruit seedlings. The increase in the salinity of the water caused negative effects on the characteristics the growth and photosynthetic pigments.

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 Lisianthus (Eustoma grandiflorum) is a cut flower grown due to the wide diversity of colors and longevity in the post-harvest. The leaf area measurement is fundamental in plants because the leaves are directly related to several processes such as transpiration, radiation interception and CO2 fixation that enable the plant to grow. The objective of the work was to determine an allometric equation for estimating the leaf area of lisianthus from linear dimensions. 200 leaves were collected and the leaf length (L), leaf width (W), product between length and width (LW) and real leaf area (LA) were measured. The criteria for determining the best model were the highest determination coefficient (R2), Willmott's concordance index (d), lowest Akaike information criterion (AIC), root mean square error (RMSE) and BIAS index closest to zero. The most suitable model for estimating the leaf area of lisianthus is the linear ŷ = 1.387*LW.

RESUMO: Mesosphaerum suaveolens (L.) Kuntze é uma espécie muito utilizada na medicina popular e que possui um elevado potencial aromático e terapêutico. No entanto, sua exploração em regiões semiáridas pode ser limitada em função do teor de sais na água de irrigação. O objetivo deste estudo foi avaliar o efeito do ácido salicílico (AS) como mitigador do estresse salino sobre o crescimento e trocas gasosas de M. suaveolens. O delineamento estatístico utilizado foi o de blocos casualizados, em esquema fatorial incompleto (Delineamento Composto Central), com cinco condutividades elétricas de água (CEa = 0,5, 1,45, 5,0, 8,55 e 10,0 dS m-1) e cinco doses de AS (0,0, 0,29, 1,0, 1,71 e 2,0 mM). Foram avaliados a altura de plantas, número de folhas, diâmetro do caule, área foliar, comprimento de raiz e relação altura/diâmetro do caule e trocas gasosas (condutância estomática, taxa de assimilação líquida de CO2, transpiração, eficiência instantânea e eficiência intrínseca no uso da água e de carboxilação e a temperatura foliar). A aplicação do AS na dose de 0,9 mM atenua o efeito do estresse salino sobre o número de folhas e área foliar. A aplicação de AS estimula o número de folhas e o crescimento em altura e da raiz, mas não afeta as trocas gasosas. A CEa reduz o crescimento e as trocas gasosas das plantas de M. suaveolens.

ABSTRACT: Mesosphaerum suaveolens (L.) Kuntze is a species widely used in folk medicine and has a high aromatic and therapeutic potential. However, its cultivation in semi-arid regions can be limited by salts in the irrigation water. The objective of this study was to evaluate the effect of salicylic acid (SA) as a mitigator of saline stress on the growth and gas exchange of M. suaveolens. The experimental design used was the randomized blocks in an incomplete factorial scheme (Central Composite Design), with five electrical conductivities water (ECw = 0.5, 1.45, 5.0, 8.55, and 10.0 dS m-1) and five SA doses (0.0, 0.29, 1.0, 1.71, and 2.0 mM). Plant height, number of leaves, stem diameter, leaf area, root length, and height/diameter ratio, and gas exchange (stomatal conductance, net CO2 assimilation rate, transpiration rate, instantaneous, and intrinsic water use efficiency, instantaneous carboxylation efficiency, and leaf temperature) were evaluated. The application of 0.9 mM SA attenuates the negative effect of saline stress on the number of leaves and leaf area of M. suaveolens. The application of SA stimulates the number of leaves, plant height, and root growth, but does not affect the gas exchange of M. suaveolens. ECw reduces the growth and gas exchange of M. suaveolens plants.

Abstract Microalgae are considered a rich source of biostimulants for plants, as an excellent business opportunity for the agricultural sector, as they can activate plant metabolism, contributing to the improvement in physiological performance, phytomass and, subsequently, vigor and quality of seedlings. The objective of this work was to evaluate the potential of Spirulina platensis biomass, in enabling improvements in physiological performance, phytomass and, subsequently, vigor and quality of cashew rootstock seedlings. The experiment was carried out in a greenhouse in a completely randomized design, in a 4 x 2 factorial scheme (concentrations x rootstock), with three replications. The concentrations used were 0%, 0.04%, 0.08%, and 0.12% and the FAGA and CCP 76 genotypes. The seeds were immersed in the solutions for 12 hours. Applications were made via the leaves at 30 days after sowing (DAS), with an interval of seven days between each application and at 90 DAS evaluations were made. The FAGA and CCP 76 genotypes showed a positive response to the supply of S. platensis, with concentrations 0.04% and 0.08% which provided greater root length, aerial part length, number of leaves, diameter and leaf area. Concentrations 0.04% and 0.08% also promoted better percentages in the physiology of the CCP 76 genotype, while the FAGA genotype showed opposite action, which may be related to the mode of action of the microalgae on the different genetic and phenotypic characteristics of each genotype. The 0.12% concentration provided greater accumulations of aerial part and total dry mass to the genotypes.

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 Bell pepper (Capsicum annuum) is one of the most consumed vegetables around the world. Balanced fertilization is essential for growing this vegetable. The objective of this study was to evaluate the yield and morphological attributes of bell pepper under doses and times of application of biological fertilizers. Two experiments were carried out with applications of biological fertilizers prepared from manure and enriched organic compounds with cattle manure and sheep manure. The experimental design was a randomized complete block design, in a 4 x 3 + 1 factorial scheme, with three replications, referring to doses of biological fertilizers (100, 200, 300 and 400 L ha-1), times of application (0, 30 and 60 days after transplanting - DAT) and control. The evaluated variables were: total fruit weight (TFW), number of commercial fruits (NCF), number of non-commercial fruits (NNCF), fruit weight (FW), fruit diameter (FD), fruit length (FL), resistance of fruit peel (RFP), number of flower buds (NFB) and productivity (P). Biological fertilizers caused positive effects on TFW, NCF, FW and P of bell pepper. The application of cattle manure at 60 DAT and sheep manure at 30 DAT promoted a larger fruit diameter. The FW, FL and RFP were influenced by the doses and times of application of biological fertilizers. The application of biofertilizers is efficient in the production of bell pepper.

Resumo A determinação da área foliar é de fundamental importância em estudos ecofisiológicos que buscam entender a relação planta-ambiente. Objetivou-se com esta pesquisa determinar uma equação alométrica que permita estimar a área foliar de Mesosphaerum suaveolens a partir de medidas lineares do limbo foliar (comprimento e/ou largura). Coletaram-se 900 limbos foliares aleatórios de diferentes formas e tamanhos, em uma área de Caatinga antropizada, localizada no município de Santa Luzia, estado da Paraíba, nordeste do Brasil. Para a construção das equações alométricas utilizaram-se os seguintes modelos de regressão: linear, linear sem intercepto, quadrático, cúbico, potência e exponencial. O modelo linear sem intercepto utilizando o produto entre comprimento e largura (C.L) foi o mais indicado para estimar a área foliar de M. suaveolens, com maior coeficiente de determinação (R2) e índice de concordância de Willmott (d), menor erro absoluto médio (MAE), critério de informação de Akaike (AIC) e raiz do quadrado médio do erro (RQME), e índice BIAS mais próximo de zero (R2 = 0,9971; d = 0,9989; MAE = 0,422; AIC = 2094,69; RQME = 0,770; BIAS = -0,0105). A área foliar de M. suaveolens pode ser estimada satisfatoriamente pela equação AF = 0,6787*(C.L).

Abstract The determination of leaf area is of fundamental importance in ecophysiological studies that seek to understand the plant-environment relationship. The objective of this research was to determine an allometric equation to estimate the leaf area of Mesosphaerum suaveolens from linear measures of leaf blade (length and/or width). There were collected 900 random leaf limbs of different shapes and sizes, in an anthropic area of caatinga, located in the municipality of Santa Luzia, state of Paraíba, Northeast of Brazil. For the construction of the allometric equations the following regression models were used: linear, linear without intercept, quadratic, cubic, power, and exponential. The linear model without intercept using the product between length and width (C.L) was the most recommended to estimate the leaf area of M. suaveolens, with greater coefficient of determination (R2) and Willmott concordance index (d), lesser mean absolute error (MAE), Akaike information criterion (AIC) and root-mean-square error (RQME), and the closer the BIAS ratio is to zero (R2 = 0.9971; d = 0.9989; MAE = 0.422; AIC = 2094.69; RQME = 0.770; BIAS = -0.0105). The leaf area of M. suaveolens can be estimated satisfactorily by equation AF = 0.6787*(C.L).