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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.

O maracujá é uma das principais frutíferas produzidas e consumidas no Brasil, sendo que a região Nordeste é considerada a de maior produção. No entanto, o excesso de sais no solo e nas águas utilizadas na irrigação da região é prejudicial ao desenvolvimento das plantas. Nesse sentido, a adubação com nitrogênio (N) e potássio (K) se torna uma estratégia para minimizar os danos promovidos pelo estresse salino. Objetivou-se avaliar o crescimento e a eficiência fotoquímica de mudas de maracujazeiro submetidas ao estresse salino e adubação foliar com nitrogênio e potássio. O experimento foi realizado no Centro de Ciências Agrárias, Universidade Federal da Paraíba, Areia-PB. O delineamento experimental utilizado foi o de blocos casualizados, em esquema fatorial incompleto, com cinco níveis de condutividade elétrica da água de irrigação (CEa = 0,50; 0,98; 2,15; 3,32 e 3,80 dS m-1) e cinco doses de N e K (0,0; 29,08; 100; 170,92 e 200%), totalizando nove combinações, geradas através da matriz Composto Central de Box, com quatro repetições e duas plantas por parcela. Foram avaliados a altura de plantas, o diâmetro caulinar, a área foliar, a razão de área foliar, a fluorescência inicial, a máxima e variável, a razão Fv/F0 e o rendimento quântico do fotossistema II. A salinidade promove redução no crescimento e nos índices de fluorescência da clorofila a das mudas de maracujazeiro. A adubação foliar com N e K ocasiona maior crescimento e incrementos nos índices de fluorescência da clorofila a. Palavras-chave: Passiflora edulis f. favicarpa. Estresse Salino. Fluorescência da Clorofila. Abstract Passion fruit is one of the main fruit produced and consumed in Brazil, and the Northeast region is considered the one with the highest production. However, the excess of salts in the soil and water used for irrigation in the region is detrimental to the plants development. In this sense, fertilization with nitrogen (N) and potassium (K) becomes a strategy to minimize the damage caused by salt stress. The objective was to evaluate the growth and photochemical efficiency of passion fruit seedlings submitted to saline stress and foliar fertilization with nitrogen and potassium. The experiment was carried out at Center for Agricultural Sciences, Federal University of Paraíba, Areia-PB. The experimental design used was randomized blocks, in an incomplete factorial scheme, with five levels of electrical conductivity of irrigation water (CEa = 0.50; 0.98; 2.15; 3.32 and 3.80 dS m- 1) and five doses of N and K (0.0; 29.08; 100; 170.92 and 200%), totaling nine combinations, generated through the Central Box Compound matrix, with four replicates and two plants per plot. Plant height, stem diameter, leaf area, leaf area ratio, initial, maximum and variable fluorescence, Fv / F0 ratio and quantum yield of photosystem II were evaluated. Salinity promotes a reduction in chlorophyll a growth and fluorescence rates of passion fruit seedlings. Foliar fertilization with N and K causes greater growth and increases in chlorophyll a fluorescence indices. Keywords: Passiflora edulis f. favicarpa. Saline Stress. Chlorophyll Fluorescence.

Production of Physalis peruviana L. has gained prominence in Northeastern Brazil. However, salinity limits the crop development in the Brazilian semiarid. Thus, this research aimed to evaluate the application of Acadian® biostimulant as mitigant of the deleterious effects of salinity on growth and gas exchange of P. peruviana plants. The experiment was combining different electrical conductivity of irrigation water (0.50, 1.23, 3.00, 4.44, and 5.50 dS m−1) and biostimulant doses (0.00, 1.45, 5.00, 8.55, and 10.00 mL L−1). The main variables evaluated were plant height, stem diameter, number of leaves, root length, leaf area, specific leaf area, leaf area ratio, absolute and relative growth rate for plant height, and gas exchange. Experimental results showed that an increase in electrical conductivity of irrigation water had negatively affected the growth components and gas exchange in P. peruviana. Also, the application of seaweed-based biostimulant improves the photosynthetic capacity (43.3%), reduces transpiration rate (26.5%) and water loss by this process, further it attenuated the deleterious effects of salinity on specific leaf area, leaf area ratio, and stomatal conductance. To further elucidate the effectiveness of biostimulant application as a mitigant of salt stress, research aimed at the biochemical and enzyme activities of the plant's antioxidant system should be conducted to better understand this process.

Brazil is one of the largest melon (Cucumis melo) producers in the world and most of the production is exported to international markets. Currently, over 15% of the Brazilian melon shipments are lost during export transportation due to Fusarium fruit rot, which is jeopardizing the livelihood of the Brazilian melon producers. Herein, we focused on understanding the aggressivity of five different species of Fusarium causing fruit rot on the main types of melon produced in Brazil. We also investigated the correlation between pathogenicity and fruit quality. Experiments were performed under a completely randomized experimental design, in a 5x8 factorial scheme, using two methodologies for inoculation: deposition of discs of culture media containing fungal structures and deposition of spore suspensions in needle-punctured lesions. The fungal species used were Fusarium falciforme, F. sulawesiense, F. pernambucanum, F. kalimantanense, and Fusarium sp. Fruits of two hybrids from four types of melons, Canary (Goldex and Gold Mine), Piel de Sapo (Grand Prix and Flecha Verde), Galia (McLaren and DRG3228), and Cantaloupe (SV1044 and Bonsai), were used. Disease severity was assessed by measuring the lesions, disease severity index, fruit firmness, and degrees Brix of fruits. The five Fusarium spp. caused rot in the fruits of all melon hybrids studied and the aggressivity of those fungal species varied with the type/hybrid of melon fruits studied. Fruits of the hybrids McLaren and Bonsai presented the largest lesions among all melon hybrids, and hybrids of Canary type (Gold Mine and Goldex) were the most tolerant to rot caused by the Fusarium species investigated. Furthermore, the greater the severity of Fusarium fruit rot, the lower the pulp firmness of the melon fruits but degrees Brix did not correlate with the onset of the disease.

Physalis peruviana L. has great exploitation potential especially for small producers in the Brazilian Northeast. However, production in semiarid regions may be limited by high salt content in soils and water sources used for irrigation. Thus, this study evaluated the application of Ascophyllum nodosum seaweed extract as saline stress attenuator in P. peruviana L. The randomized block design was used, in an incomplete 5 × 5 factorial scheme, with five of electrical conductivities of the irrigation water (0.50, 1.23, 3.00, 4.77 and 5.50 dS m-1) and five increasing concentrations of kelp extract (0.00, 1.45, 5.00, 8.55 and 10.00 mL L-1), with nine combinations generated by the Central Box matrix, with four replicates of four plants to evaluate the effect on phytomass accumulation, chlorophyll fluorescence and pigment content. Results showed, salinity significantly reduced biomass production and chlorophyll fluorescence and pigment indices. However, when plants were treated with 9.9 mL L-1 seaweed extract they increased biomass production and seedling quality. On the other hand, up to 4.1 mL L-1, the biostimulant increased dark-adapted fluorescence indices which indicate it reduces damages to the photosynthetic apparatus caused by salt-stress and thus improving photosynthetic activity and photoassimilates production. Thus the application of A. nodosum seaweed extract attenuates the deleterious effect of salt stress in photosynthesis and thus in biomass production of P. peruviana plants.

Grapes are very appreciated as a functional food due to the high content of bioactive compounds, such as polyphenols and anthocyanins, important for human health. These properties can be improved t...

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. 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.

A alfazema é uma espécie medicinal amplamente utilizada na medicina popular, especialmente na região Nordeste do Brasil. Contudo, seu crescimento pode ser limitado pelo excesso de sais na água utilizada na irrigação, sendo necessária a busca por alternativas que minimizem os efeitos. Assim, objetivou-se avaliar o condicionamento osmótico das sementes nas características de crescimento e fluorescência da clorofila ‘a’ em plantas de M. suaveolens sob estresse salino. O delineamento estatístico foi o de blocos casualizados em esquema fatorial incompleto 5x5 com cinco níveis de condutividade elétrica da água de irrigação (0,5; 1,45; 5,00; 8,55; e 10,0 dS m-1) e cinco potenciais osmóticos (0,0; -0,15; -0,50; -0,85; e -1,0 MPa), com quatro repetições constituídas de duas plantas, totalizando nove combinações geradas através da matriz Composto Central de Box. Foram avaliadas as características de crescimento e os parâmetros de fluorescência da clorofila ‘a’ aos 45 dias após o início da aplicação das águas salinas. Os dados foram submetidos aos testes de normalidade (Shapiro-Wilk) e de homogeneidade das variâncias (Bartlett). Após os dados terem atendido aos pressupostos, os mesmos foram submetidos à análise de variância pelo teste F, nos casos de significância foi realizada análise de regressão polinomial. As características de crescimento foram afetadas severamente pelo aumento da salinidade da água de irrigação. Salinidade acima de 3,9 dS m-1 reduz todos os parâmetros de fluorescência da clorofila a em plantas de alfazema brava. O osmocodicionamento das sementes com polietilenoglicol atenua os efeitos negativos da salinidade sobre a emissão de folhas. O condicionamento das sementes com PEG estimula a atividade dos índices de fluorescência da clorofila ‘a’.

SUMMARY: Ecophysiological studies are highly important to seek understanding of the plant-environment relationship. The objective of this work was to evaluate the influence of environmental factors on physiological aspects in young plants of Erythroxylum pauferrense throughout the day. A completely randomized design with 10 treatments and 4 replicates was used. Treatments were at different evaluation times throughout the day (8:00 h-17:00 h) with a 60-minute interval between them. The physiological variables evaluated were: photosynthesis rate, internal CO2 concentration, transpiration, stomatal conductance, vapor pressure deficit, instantaneous water use efficiency, intrinsic water use efficiency, instantaneous carboxylation efficiency and leaf temperature. Internal and external temperature, relative humidity of the internal and external air of the greenhouse and photosynthetically active radiation were measured as climatic variables. The climatic variables presented correlations with the physiological parameters, with a strong association between photosynthetically active radiation and internal and external temperature of the greenhouse with the rate of photosynthesis, vapor pressure deficit, leaf temperature, transpiration, intrinsic efficiency of the use of water, stomatal conductance and instant water use efficiency. The influence of climatic factors on the physiological aspects in plants of E. pauferrense can be observed. The most suitable period of the day for conducting the physiological evaluations in species is between 11:00 h and 13:00 h.

Mesosphaerum suaveolens (L.) Kuntze is a species of high phytotherapeutic and aromatic potential and quite widespread in Northeastern Brazil. However, the scarcity of good quality water and the high content of salts contained in the soil and irrigation water of the semi-arid region can compromise the crop growth and yield . Therefore, this study aimed to evaluate the effect of seed treatment with salicylic acid on the growth rates and the fluorescence indexes of chlorophyll ‘a’ from M. suaveolens plants irrigated with saline waters. The experiment was conducted in a randomized complete block design with a 5 x 5 incomplete factorial design, with five electrical conductivities of the irrigation water (ECw = 0.5, 1.45, 5.00, 8.55 and 10.0 dS m-1) and five salicylic acid doses (SA = 0.0, 0.29, 1.0, 1.71 and 2.0 mM L-1), generated by the Box Central Compound matrix. The evaluated variables were the absolute and relative growth rates for stem height and diameter and the indexes of fluorescence and quantum yield of photosystem II. The salinity of the water reduces the growth and the fluorescence indexes of the plants. The seeds treatment with salicylic acid at the doses of 1.99 and 0.69 mM L-1 attenuates the damaging effect from saline stress on the absolute and relative growths for the stem diameter.

A melancia é uma olerícola relevante para o Brasil, inclusive para a região Nordeste. No entanto, a sua produção é afetada pelo excesso de sais na água de irrigação dessa região. O ácido salicílico é uma substância que vem sendo utilizada como mitigadora dos efeitos desses estresses sobre as plantas. Assim, objetivou-se avaliar o tratamento de sementes com ácido salicílico como atenuante da salinidade sob o crescimento inicial de melancia. O experimento foi conduzido em delineamento em blocos casualizados, com esquema fatorial incompleto 5 x 5, sendo cinco concentrações de ácido salicílico (AS - 0,00; 0,15; 0,50; 0,85 e 1,00 mM) e cinco condutividades elétricas da água de irrigação (CEa - 0,50; 1,01; 2,25; 3,49 e 4,00 dS m-1), totalizando 9 combinações geradas através da matriz Composto Central de Box. Foram avaliados a porcentagem e índice de velocidade de emergência, comprimento de raiz, parte aérea e de plântulas e massa seca de plântulas. Não houve efeito significativo para a interação entres os fatores avaliados. O aumento da CEa afetou negativamente a velocidade de emergência, o comprimento e a massa seca de plântulas. A dose de 1,0 mM de ácido salicílico estimulou o crescimento da parte aérea e de plântulas.

The salinity of irrigation water is one of modern agriculture’s major obstacles, as it can damage the plants metabolism and, consequently, its development. Currently there is a great demand for substances that may mitigate such effects, such as salicylic acid. Thus, this study aimed to evaluate the effects of salicylic acid application on watermelon plants (Citrullus lanatus L.) under salinity stress. The experimental design was a randomized block design, in an incomplete factorial scheme, with four replications and two plants per replicate. The treatments resulted from the combination of five concentrations of salicylic acid (0.00, 0.15, 0.50, 0.85 and 1.00 mM) and five electrical conductivities of the irrigation water (0.50, 1.01, 2.25, 3.49 and 4.00 dS m-1). The development, gas exchange, chlorophyll index and fluorescence were evaluated 30 days after transplanting. This data was submitted to analysis of variance and then confidence bands (confbands) and Pearson correlation were produced. The application of salicylic acid (up to 0.85 mM) promotes beneficial effects for the watermelon plants morphophysiology, while the increase in electrical conductivity of the irrigation water is harmful.

Zucchini (Cucúrbita pepo L.) has a great economic and productive potential in the semi-arid region of Brazil, due to the wide acceptance by consumers and quick financial return. The nitrate (NO3 -) assimilation process in C3 plants such as zucchini is related to photorespiration, and Si accumulated near the stomata reduces the transpiration rate, making the photosynthesis cycle more efficient. The objective of this study was to evaluate the interaction between nitrogen and silicon fertilization on growth, chlorophyll index, and chlorophyll a fluorescence of zucchini plants. The treatments were distributed in a split-plot scheme in a randomized block design with three replicates. The plot was arranged by silicon levels (0 and 6 g/plant) and the subplots constituted by five nitrogen levels (30, 60, 90, 120 and 150 kg ha-1). Leaf, stem and total dry masses, chlorophyll a, chlorophyll b, total chlorophyll, chlorophyll a/b ratio and chlorophyll a fluorescence were evaluated. The highest dry matter productions in zucchini were obtained in treatments without Si. Si and N application together positively influences the chlorophyll a/b ratio of zucchini plants. The interaction between Si and N positively influences the maximum fluorescence, variable fluorescence and quantum yield of photosystem II of zucchini plants. RESUMEN El calabacín (Cucurbita pepo L.) presenta un gran potencial económico y productivo en la región semiárida de Brasil, debido a su amplia aceptación por los consumidores y su rápido rendimiento financiero., El proceso de asimilación de nitrato (NO3 -) en plantas C3 como el calabacín estaría relacionado en parte con la fotorrespiración, y el Si acumulado cerca de los estomas reduce la tasa de transpiración, haciendo que el ciclo de fotosíntesis sea más eficiente. Por lo tanto, el objetivo de este estudio fue evaluar la interacción entre el nitrógeno y la fertilización con silicio en el crecimiento, el índice de clorofila y la fluorescencia de la clorofila a en plantas de calabacín. Los tratamientos se distribuyeron en un esquema de parcelas divididas en un diseño de bloques al azar con tres repeticiones. La parcela se formó por niveles de silicio (0 y 6 g/planta) y las subparcelas constituidas por cinco niveles de nitrógeno (30, 60, 90, 120 y 150 kg ha-1), totalizando 30 parcelas experimentales. Se evaluaron masas de hojas, tallos y secas totales, clorofila a, clorofila b, clorofila total, clorofila a/b y fluorescencia de la clorofila a. Las mayores producciones de materia seca de calabacín se obtuvieron en tratamientos sin Si. La aplicación de Si y N juntos influye positivamente en la proporción de clorofila a/b de las plantas de calabacín. La interacción entre Si y N influye positivamente en la fluorescencia máxima, la fluorescencia variable y el rendimiento cuántico del fotosistema II de plantas de calabacín.

Root-knot nematodes are the main soil-dwelling phytopathogens that cause severe damages to plants, especially tomato plants. Exogenous application of salicylic acid (SA) can mitigate such pathogenicity. This work aimed to evaluate the growth of tomato plants submitted to Meloidogyne javanica population densities (PD) and application of SA. The experiment was a randomized block design, in an incomplete factorial scheme (central composite design), with five PD (0, 5815, 20000, 34184, and 40,000 eggs per pot) and five SA doses (0.0, 0.29, 1.0, 1.71, and 2.0 mM), with four replicates containing two plants each. Number of leaves, plant height, stem diameter, shoot dry mass, root dry mass and total dry mass, Dickson's quality index, leaf area, specific leaf area, specific leaf weight, root volume, absolute and relative growth rates for plant height, number of eggs, number of galls, and nematode reproduction factor were evaluated at 50 days after soil inoculation (DAI). Results showed the application of 0.97, 2.0, and 0.88 mM SA increased, respectively, the RGR, SLA and SLW. On the other hand, 0.91 and 0.93 mM SA decreased, respectively, the number of eggs and reproduction factor of nematodes. Also, M. javanica did not affect the growth of tomato plants until 50 DAI. Keywords: Meloidogyne javanica; phytohormone; Solanum lycopersicum. Morfologia do tomateiro sob ataque de nematoides e aplicação de ácido salicílico RESUMO: Nematoides das galhas são uns dos principais patógenos de solo que causam danos severos nas plantas, especialmente em plantas de tomate. A aplicação exógena de ácido salicílico (AS) pode minimizar os efeitos desses patógenos. O objetivo deste trabalho foi avaliar o crescimento de plantas de tomate submetidas à densidades populacionais de Meloidogyne javanica (DP) e aplicação de AS. O delineamento em blocos casualizados em esquema fatorial incompleto (Composto Central de Box) com cinco DP (0, 5815, 20000, 34184 e 40000 ovos por planta) e cinco doses de AS (0.0, 0.29, 1.0, 1.71 e 2.0 mM), com quatro repetições e duas plantas por repetição foi utilizado. O número de folhas, altura de planta, diâmetro do caule, massa seca da parte aérea, raiz e total, índice de qualidade de Dickson, área foliar, área foliar específica, peso específico de folha, volume de raiz, taxas de crescimento absoluto e relativo para altura, número de ovos, número de galhas e fator de reprodução dos nematoides foram avaliados aos 50 dias após a inoculação do solo (DAI). A aplicação de 0.97, 2.0 e 0.88 mM de AS aumentam a taxa de crescimento relativo de altura, área foliar específica e peso específico de folhas, respectivamente. A aplicação de 0.91 e 0.93 mM de AS diminuem o número de ovos por grama de raiz e fator de reprodução, respectivamente. M. javanica não influenciou o crescimento de plantas de tomate até 50 DAI. Palavras-chave: Meloidogyne javanica; fitohormônio; Solanum lycopersicum., Los nematodos agalladores son uno de los principales patógenos del suelo que causan graves daños a las plantas, especialmente a las de tomate. La aplicación exógena de ácido salicílico (SA) puede minimizar los efectos de estos patógenos. El objetivo de este trabajo fue evaluar el crecimiento de plantas de tomate sometidas a densidades poblacionales de Meloidogyne javanica (DP) y aplicación de AS. Un diseño de bloques al azar en un esquema factorial incompleto (Central Box Composite) con cinco DP (0, 5815, 20000, 34184 y 40000 huevos por planta) y cinco dosis de AS (0.0, 0.29, 1.0, 1.71 y 2.0 mM), con Se utilizaron cuatro repeticiones y dos plantas por repetición. El número de hojas, la altura de la planta, el diámetro del tallo, el brote, la raíz y la masa seca total, el índice de calidad de Dickson, el área foliar, el área foliar específica, el peso específico de la hoja, el volumen de la raíz, las tasas de crecimiento absoluto y la altura relativa, el número de huevos, el número de agallas y factor de reproducción de nematodos se evaluaron 50 días después de la inoculación del suelo (DAI). La aplicación de 0,97, 2,0 y 0,88 mM de AS aumenta la tasa de crecimiento relativo de altura, área foliar específica y peso específico de las hojas, respectivamente. La aplicación de 0,91 y 0,93 mM de AS disminuye el número de huevos por gramo de raíz y factor de reproducción, respectivamente. M. javanica no influyó en el crecimiento de las plantas de tomate hasta 50 DAI.

Salinity is one of the modern agriculture major obstacles, causing several physiological disturbances in plants, adversely affecting its growth and development. Therefore, some techniques are required in order to alleviate the negative effects of salinity stress on plants, as for example an adequate nitrogen fertilization. The aim of this study was to assess the ecophysiological responses of sugar apple plants (Annona squamosa L.) submitted to different salinity levels and nitrogen fertilization doses. The experimental design was a randomized block in an incomplete factorial scheme, with five electrical conductivities of the irrigation water (ECw: 0.5, 1.01, 2.25, 3.49 and 4.0 dS m-1) and five nitrogen doses (0, 101, 350, 598.2 and 700 mg dm-3), with four replicates, generated from the Box Central Composite experimental design matrix. Through a daily course, it was observed variations in gas exchange, chlorophyll content and fluorescence parameters. The gas exchange, chlorophyll content and fluorescence parameters were measured on photosynthetically active leaves. There was significant interaction between the salinity levels (ECw) and nitrogen doses for the chlorophyll indexes. The electrical conductivity of the irrigation water caused significant negative effects on chlorophyll fluorescence. Therefore, it can be stated that the sugar apple plants ecophysiology varies through the day and that salinity affects its chlorophyll content and fluorescence.

Erythrina velutina é uma espécie endêmica da região Nordeste do Brasil, conhecida por exibir propriedades farmacológicas e potencial madeireiro. Entretanto, seu crescimento pode ser comprometido por fatores abióticos como escassez hídrica e excesso de sais. A utilização de reguladores de crescimento como o ácido salicílico está entre os métodos usados para mitigar os efeitos negativos de estresse nos vegetais. Com isso, objetivou-se avaliar o crescimento de mudas de Erythrina velutina submetida ao estresse salino e aplicação de ácido salicílico. O delineamento utilizado foi em blocos casualizados, em esquema fatorial incompleto 5 x 5, gerados a partir da matriz Composto Central de Box com cinco níveis de condutividade elétrica da água de irrigação (CEa= 0,5; 1,74; 4,75; 7,76 e 9,0 dS m-1) e cinco doses de ácido salicílico (AS= 0,0; 0,29; 1,0; 1,71 e 2,0 mM L-1), com quatro repetições. Foram avaliadas as variáveis: altura da planta, número de folhas, diâmetro do caule, taxa de crescimento relativo e absoluto da altura e diâmetro do caule, massa seca de raiz, do caule, da parte aérea e total e o índice da qualidade de Dickson. Os dados foram submetidos à análise de variância pelo teste F, nos casos de significância foi realizada análise de regressão polinomial. A salinidade promove sérios danos ao crescimento das plantas de Erythrina velutina, sendo mais acentuado nos níveis crescentes de condutividade elétrica. A aplicação de ácido salicílico nas concentrações utilizadas não atenua os efeitos da salinidade.

Aims: The objective of this work was to evaluate the effect of nitrogen fertilization on the production of Tamarindus indica L. seedlings irrigated with saline water. Study Design: A randomized complete block design was used in a 4 x 4 factorial scheme, whose factors were the electrical conductivity levels of the irrigation water. Place and Duration of Study: The work was conducted under protected environment conditions (greenhouse) at the Federal University of Campina Grande, Center for Agro-Food Sciences and Technology, Campus of Pombal-PB, Brazil, in the period from January and March 2017. Methodology: Effects of doses of 0, 100, 200 and 300 mg of nitrogen (N) dm-3 and electrical conductivity levels of the irrigation water (ECw) (0.3, 2.1, 3.7 and 5.2 dS m-1) on growth of Tamarindus indica L. have been studied. Results: The growth of the seedlings was reduced by the increase of the electrical conductivity of the irrigation water, however, irrigation with ECw water of 2.15 dS m-1, promotes acceptable reductions of 10% in the morphology of the tamarind tree. Conclusion: The use of nitrogen fertilization with urea did not attenuate the deleterious effects of irrigation water salinity or promoted improvements of the quality of the tamarind seedlings.

Aims: The study was conducted to evaluate the fluorescence and growth of eggplant under influence of water deficit and silicon doses. Study Design: The design was a randomized complete block design, in a 5 x 2 factorial arrangement, with four replications and one plant per plot, totaling 40 experimental units. Length and Place of Study: The research was implemented between September and November 2016, in a greenhouse of the Center of Science and Technology Agrifood, at the Federal University of Campina Grande (UFCG / CCTA), Campus of Pombal-PB, Brazil. Methods: Doses of 0, 75, 150, 225 and 300 mg L-1 of silicon and the irrigation slides of 50 and 100% of real evapotranspiration - ETr were used, which were obtained by weighing the pots daily in order to keep the weight close to the field capacity. Results: The use of 50% level of the ETr provides reductions of 5.58; 7.92 and 6.84% of fluorescence in the initial, maximum and quantum yield of the photosystem. The fresh and dry mass of the stem presented the maximum productivity (140.8 and 48.1 g) in the plants irrigated with 100% Etr and treated with doses of 106 and 110 mg L-1 of Si. Conclusion: The fluorescence and biomass of the eggplant plants is reduced with the decrease in irrigation level; while the application of silicon does not result in increment in the fluorescence and dry mass of the leaf. The 100% irrigation level of the ETr associated with the application of 108 mg L-1 of silicon resulted in the best results in stem mass accumulation.

A escassez hídrica é um problema para a produção agrícola nas regiões semiáridas, de forma que torna-se necessário estudar seus efeitos, assim como medidas para atenuar tais danos na germinação e crescimento inicial das plântulas. Objetivou-se avaliar o ácido salicílico (AS) como atenuador do estresse durante a germinação de sementes e crescimento inicial das plântulas de Cereus jamacaru. O experimento foi conduzido em delineamento inteiramente casualizado em esquema fatorial 5 x 5, sendo cinco potenciais osmóticos (0,0; -0,2; -0,4; -0,8 e -1,2MPa) induzidos por polietilenoglicol (PEG 6000) e cinco doses de AS (0,0; 0,29; 1,0; 1,71 e 2,0 mM L-1). As avaliações realizadas foram: porcentagem de germinação, primeira contagem, índice de velocidade, tempo médio e velocidade média de germinação, comprimento, massa fresca e seca de plântulas. O estresse hídrico induzido por soluções de PEG 6000 reduz a qualidade e o vigor das sementes de C. jamacaru. A embebição de sementes com AS atenua o efeito déficit hídrico, sendo a dose de 1,71 mM L-1 a mais eficiente para reduzir os danos promovidos pelo estresse hídrico sobre a germinação das sementes de C. jamacaru.

Salinity is one of the main plant abiotic stresses affecting the establishment and development of crops. It is thus a matter of prime importance to search for technologies that minimize the damage caused by salinity. The aim of the present work was to evaluate the effect of salinity stress and osmotic conditioning of seeds on the biomass, gas exchanges and chlorophyll pigments in Mesosphaerum suaveolens (L.) Kuntze. The statistical design adopted was a randomized block design, combined according to the central composite design, referring to electrical conductivities of irrigation water and osmotic potentials, with minimum (- α) and maximum (α) values of 0.5 and 10.0 dS m-1 and 0.0 and -1.0 MPa, respectively, totaling nine combinations. The characteristics of dry biomass, gas exchange and chlorophyll indices were evaluated at 45 days after the beginning of irrigation with saline water. The salinity of irrigation water severely affected the dry biomass and the gas exchanges of M. suaveolens. Irrigation water of electrical conductivity above 3.2 dS m-1 caused reductions in chlorophyll a, b and total contents in M. suaveolens plants. Seed osmoconditioning did not attenuate the negative effects of saline stress on M. suaveolens plants.

Seasonal variation affects understory and canopy tree plants in different ways.Palicourea racemosais an understory shrub from the Rubiaceae family and is subject to seasonal oscillations of the environment, which can affect plant ecophysiological responses. This species is widely distributed in humid forests from southern Mexico to southeastern Brazil and has broad economic and ecological importance for the regions of occurrence, being used for food, ornamental and traditional medicine purposes. It is of fundamental importance to know ecophysiological responses of this species throughout dry and rainy periods, to understand the dynamics of understory plants in tropical forests. This research aimed at evaluating the effects of seasonality on ecophysiological aspects ofP. racemosaat the Mata do Pau-Ferro State Park, municipality of Areia, Paraíba, Brazil. Over ten months, upper canopy structure indices were measured in ten individuals, climatic data were collected and their effects on gas exchange and chlorophyll indices in plants were evaluated. Results showed that the environmental variables correlated with the ecophysiological ones, with a strong association of soil moisture, rainfall and leaf area index of the upper canopy on ecophysiological aspects inP. racemosaplants, indicating that water availability and irradiance affect gas exchanges and photosynthetic pigment content. Except for intrinsic water use efficiency and instantaneous carboxylation efficiency, all ecophysiological variables showed significant differences over the months, showing the influence of seasonality on the ecophysiological responses ofP. racemosa., La variación estacional afecta a las plantas de árboles del sotobosque y del dosel de diferentes maneras.Palicourea racemosaes un arbusto de sotobosque de la familia Rubiaceae y está sujeto a oscilaciones estacionales del medio ambiente, que pueden afectar las respuestas ecofisiológicas de las plantas. Esta especie se encuentra ampliamente distribuida en bosques húmedos desde el sur de México hasta el sureste de Brasil y tiene una gran importancia económica y ecológica para las regiones de ocurrencia, siendo utilizada con fines alimentarios, ornamentales y de medicina tradicional. Es de fundamental importancia conocer las respuestas ecofisiológicas de esta especie a lo largo de los períodos secos y lluviosos, a fin de buscar comprender la dinámica de las plantas del sotobosque en los bosques tropicales. La investigación tuvo como objetivo evaluar los efectos de la estacionalidad en aspectos ecofisiológicos deP. racemosaen el Parque Estatal Mata do Pau-Ferro, municipio de Areia, Paraíba, Brasil. Durante diez meses, se midieron índices de estructura del dosel superiores a diez individuos, se recopilaron datos climáticos y se evaluaron sus efectos sobre el intercambio de gases y los índices de clorofila en las plantas. Las variables ambientales se correlacionaron con las ecofisiológicas, con una fuerte asociación de la humedad del suelo, las precipitaciones y el índice de área foliar del dossel superior en los aspectos ecofisiológicos deP. racemosa, resultados que indican que la disponibilidad de agua y la irradiancia afectan los intercambios de gases y el contenido de pigmentos fotosintéticos en las plantas. Excepto, por la eficiencia intrínseca del uso del agua y la eficiencia de la carboxilación instantánea, todas las variables ecofisiológicas tuvieron diferencias significativas a lo largo de los meses, debido a la influencia de la estacionalidad en las respuestas ecofisiológicas deP. racemosa.

Nematodes of the genus Meloidogyne spp. are one of the tomato culture’s main pathogens. According to their soil infestation level, physiological changes may occur. Consequently, it is extremely important to employ given products to minimize their effect. A feasible option is the salicylic acid, a phytohormone that can induce into resistance due to its ability to increase the production level of some pathogenicity proteins. Therefore, the purpose hereof was to assess the effect of salicylic acid on the physiology of tomato plants subject to different populational densities of Meloidogyne javanica. The design employed was one of randomized blocks, in an incomplete factorial scheme, using the Box Central Compound (BCC) matrix with five nematode populational densities (PD) (0; 5815; 20000; 34184; and 40000 eggs per plant) and five salicylic acid doses (0.0; 0.29; 1.0; 1.71; and 2.0 mM), with four repetitions and two plants per experimental patch. The gas exchanges, fluorescence, and chlorophyll levels were evaluated 45 days after the transplant and soil infestation. The data were submitted for analysis of variance through the F test and, in the significance cases, the polynomial regression analysis was performed. For stomatal conductance, a greater reduction was seen at the PD of 21755 eggs per plant, a fact that might have decreased the liquid assimilation of CO2 and the efficiency of carboxylation. The salicylic acid (SA) affected the CO2 liquid assimilation and the efficiency of carboxylation. The infestation of M. javanica in tomato plants negatively affected the gas exchange and the chlorophyll levels because the SA application did not mitigate the negative effect thereof. Os nematoides do gênero Meloidogyne spp. são um dos principais patógenos na cultura do tomate, podendo causar alterações fisiológicas em função do nível de infestação do solo. O uso de produtos que minimize seus efeitos é de suma importância, nesse sentido, o ácido salicílico pode ser uma alternativa viável, visto que, esse fitormônio pode induzir a resistência devido à capacidade de proporcionar um aumento na produção de algumas proteínas de patogenicidade. Com isso, objetivou-se avaliar o efeito do ácido salicílico na fisiologia do tomateiro submetido a diferentes densidades populacionais de Meloidogyne javanica. O delineamento utilizado foi o de blocos casualizados, em esquema fatorial incompleto, utilizando-se a matriz Composto Central de Box (CCB) com cinco densidades populacionais (DP) de nematoides (0; 5815; 20000; 34184 e 40000 ovos por planta) e cinco doses de ácido salicílico (0,0; 0,29; 1,0; 1,71 e 2,0 mM), com quatro repetições e duas plantas por parcela experimental. Foram avaliadas as trocas gasosas, fluorescências e índices de clorofilas aos 45 dias após o transplantio e infestação do solo. Os dados foram submetidos à análise de variância pelo teste F e nos casos de significância foi realizada análise de regressão polinomial. Para a condutância estomática, observou-se uma maior redução na DP de 21755 ovos por planta, fato que pode ter ocasionado reduções na assimilação líquida de CO2 e na eficiência de carboxilação. O ácido salicílico (AS) influenciou na assimilação líquida de CO2 e eficiência de carboxilação. A infestação por M. javanica em plantas de tomateiro influenciou negativamente nas trocas gasosas e nos teores de clorofila, sendo que a aplicação do AS não atenuou os efeitos negativos desses patógenos.

Salinity is one of the most problematic abiotic stresses in agriculture globally, especially in semi-arid regions. Thus, the application of nutrients, such as nitrogen and potassium to improve plant nutritional conditions may be a viable alternative to minimize the negative effects of saline stress. Therefore, the aim of this study was to evaluate the morphophysiological behavior of yellow passion fruit seedlings under varying nitrogen and potassium doses and irrigation with salt water. The experimental design was a randomized complete block with a 5 x 5 incomplete factorial scheme, generated from the Central Composite Design with five electrical conductivities of irrigation water (0.5, 0.98, 2.15, 3.32, and 3. 80 dS m-1) and five increasing doses of nitrogen and potassium (0.0, 29.08, 100.0, 170.92, and 200.0%). Leaf, stem, and root dry phytomass and gas exchange were evaluated 75 days after sowing. The increase in salinity had negative effects on the morphological and physiological characteristics of yellow passion fruit seedlings. The application of nitrogen and potassium positively influenced photosynthetic rate and leaf and root dry phytomasses. The application of nitrogen and potassium increased intercellular CO2 concentration and transpiration in yellow passion fruit seedlings under saline stress. A salinidade é um dos estresses abióticos mais preocupantes na agricultura mundial, principalmente nas regiões semiáridas. Assim, a aplicação de nutrientes como nitrogênio e o potássio visando melhorar as condições nutricionais das plantas pode ser uma alternativa viável para minimizar os efeitos negativos do estresse salino. Portanto, objetivou-se avaliar o comportamento morfofisiológico de mudas de maracujazeiro-amarelo sob doses de nitrogênio e potássio e irrigadas com águas salinas. O delineamento utilizado foi em blocos casualizados, em esquema fatorial incompleto 5x5, gerados a partir da matriz Composto Central de Box com cinco condutividades elétricas da água de irrigação (0,5; 0,98; 2,15; 3,32 e 3,80 dS m-1) e cinco doses crescentes de nitrogênio e potássio (0,0; 29,08; 100,0; 170,92 e 200,0%). Foram avaliadas as fitomassas seca de folha, caule e raiz e as trocas gasosas aos 75 dias após a semeadura. O aumento da salinidade proporciona efeitos negativos nas características morfofisiológicas do maracujazeiro amarelo. A aplicação de nitrogênio e potássio influencia positivamente na taxa fotossintética e fitomassa seca das folhas e raiz. A aplicação de nitrogênio e potássio aumenta concentração intercelular de CO2 e transpiração de mudas de maracujazeiro-amarelo sob estresse salino.

A barriguda [Ceiba glaziovii (Kuntze) K.Schum.] é uma espécie arbórea de elevado potencial madeireiro e bastante utilizada na recuperação de áreas degradadas. As características do ambiente influenciam diretamente no crescimento e desenvolvimento dessa espécie, sendo a disponibilidade de luz um dos mais importantes. Com isso, o objetivo do trabalho foi avaliar aspectos morfofisiológicos em plantas de C. glaziovii sob diferentes níveis de sombreamento. Utilizou-se o delineamento inteiramente casualizado, com 5 tratamentos e 8 repetições. Os tratamentos utilizados foram compostos por diferentes níveis de sombreamento: 0% (pleno sol), 30%, 50%, 70% e 90% de sombra. As avaliações foram realizadas aos 60 dias após a emergência da parte aérea. Os dados foram submetidos à análise de variância pelo teste F, e nos casos de significância realizou-se a análise de regressão polinomial. As condições de sombreamento influenciaram nas características morfofisiológicas de plantas jovens de C. glaziovii. O sombreamento acima de 70% proporcionou condições favoráveis para a produção de mudas de C. glaziovii.

Salinity is one of the factors that negatively impact plant growth and productivity; therefore, it is necessary to seek solutions that help mitigate the degenerative action of saline stress on crops. The objective of this study was to evaluate the effects of salicylic acid (SA) on the germination and vigor of Mesosphaerum suaveolens (L.) Kuntze seeds subjected to salinity. The experiment was carried out using a completely randomized design, in an incomplete 5 × 5 factorial scheme, with five levels of electrical conductivity of irrigation water (ECw - 0.0, 1.45, 5.00, 8.55, and 10.00 dS m-1) and five doses of SA (0.0, 0.29, 1.00, 1.71, and 2.00 mM), with four replications of 50 seeds, totaling nine combinations generated via a central composite design. The germination percentage, first germination count, germination speed index, average germination time, percentage of abnormal seedlings, shoot, root, and seedling lengths, and total seedling dry mass were evaluated. Salicylic acid attenuated the effect of saline stress on initial growth, mitigating damage to root and shoot lengths. Seed priming with salicylic acid improved germination and seed vigor. A salinidade é um dos fatores que promove a inibição no crescimento e produtividade vegetal, sendo necessária a busca por alternativas que auxiliem na mitigação da ação degenerativa do estresse salino às culturas. Objetivou-se com este trabalho avaliar doses de ácido salicílico na germinação e vigor de sementes de Mesosphaerum suaveolens (L.) Kuntze submetidas à salinidade. O experimento foi conduzido em delineamento inteiramente casualizado, em esquema fatorial incompleto 5 x 5, com cinco níveis de condutividade elétrica da água de irrigação (CEa de 0,0; 1,45; 5,00; 8,55 e 10,00 dS m-1) e cinco doses de AS de (0,0; 0,29; 1,00; 1,71 e 2,00 mM L-1), com quatro repetições de 50 sementes, totalizando nove combinações geradas via matriz Composto Central de Box. As variáveis avaliadas foram: porcentagem de germinação, primeira contagem de germinação, índice de velocidade de germinação, tempo médio de germinação, porcentagem de plântulas anormais, comprimento da parte aérea, radícula e plântula e massa seca total de plântulas. O ácido salicílico atenua o efeito do estresse salino sobre o crescimento inicial, mitigando os danos sobre o comprimento de radícula e da parte aérea. O tratamento das sementes com ácido salicílico melhora a germinação e o vigor das sementes.

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).