Physiological indices of okra under organomineral fertilization and irrigated with salt water

HIGHLIGHTS Salt water reduces gas exchange in the okra crop, but organomineral fertilization mitigates these effects. The use of organic and mineral fertilization is viable in okra crops under salt stress. Organic fertilizer (100% bovine biofertilizer) decreases internal CO2 concentration.

Physiological response of maize under different fertilization management under drought condition

This work was aimed to evaluate the development of maize cultivated under different fertilization management, in order to establish an alternative for mineral fertilization. The experiment was carried out in the experimental area of Chã de Jardim, in Areia, Paraíba, Brazil. Six treatments were used with four replications. Plant height, stalk diameter, leaf number, chlorophyll a, b and total, photosynthetic rate, transpiration, stomatal conductance and internal CO2 concentration in the leaf were evaluated. In the 30 days after emergence, superiority of treatments was observed in the plants under chemical fertilization for plant height and number of leaves. For diameter of stalk the treatment organic fertilization + P and K showed superiority. At 60 days after planting the chemical fertilization provided the highest averages for plant height and stalk diameter. For the photosynthetic rate, transpiration and internal CO2 concentration, the treatment that presented the highest average was observed in plants under organic fertilization combined with P and K and N added in top-dressing. For the chlorophyll, the chemical fertilization provided the highest values. Organic fertilization in association with mineral fertilizers provided results close to those observed in mineral fertilization, being an alternative for nutritional management in maize.

Productive and physiological responses of jambu (Acmella oleracea) under nutrient concentrations in nutrient solution

ABSTRACT In the last years, jambu has become popular and greatly appreciated, due to its remarkable taste. Thus, hydroponically cultivated jambu is promising, since it achieves better yield and production quality. The aim of this study was to evaluate the effect of ionic concentration in nutrient solution on growth, productivity and gas exchange of jambu. The experimental design was completely randomized, with five treatments and four replicates. The treatments consisted of variations of ionic concentration using the nutrient solution proposed by Hoagland & Arnon (25, 50, 75, 100 and 125%). The length of the main stem, stem diameter, number of inflorescence, leaf area, fresh and dry biomass (shoot, root and inflorescence), photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, Ci/Ca ratio and instant carboxylation efficiency were evaluated. Ionic concentrations significantly affected the studied variables, except the stem diameter, the internal CO2 concentration and the Ci/Ca ratio. The number of inflorescences and the leaf area grew linearly with maximum values (37.8 units plant-1 and 1650.8 cm2 plant-1, respectively) obtained in ionic concentration of 125%. Maximum responses were observed for shoot fresh and dry mass (63.9 and 6.9 g plant-1), root fresh and dry mass (16.7 and 2.0 g plant-1) inflorescence fresh and dry mass (11.0 and 1.8 g plant-1), respectively, at ionic concentration of 125%. Liquid photosynthesis, stomatal conductance, transpiration and instant carboxylation efficiency achieved maximum responses of 17.9 µmol CO2 m-2 s-1, 0.3 mol H2O m-2 s-1, 6.3 mmol m-2 s-1 and 0.06 with estimated concentrations of 84, 70, 80 and 83% of ionic strength, respectively. Thus, we concluded that the ionic concentration of 125% is indicated to obtain a greater biomass accumulation.

Shading and its reflections on growth and gas exchanges of Microdesmia rigida (Benth.) Sothers & Prance

The objective of this research was to evaluate the effect of shading on growth and gas exchange of seedlings of Microdesmia rigida, keeping them under the levels of 0% (full sun), 50% and 70% shading, arranged in a completely randomized design (DIC), with four replications. Plant height, stem diameter, height/diameter ratio, absolute growth rate, leaf area, plant dry matter weight, dry root/shoot weight ratio, Dickson Quality Index (DQI), transpiration, stomatal conductance, photosynthesis rate, internal CO2 concentration, chlorophyll contents a, b and total were analysed. There was a reduction in the rate of transpiration and increase in stomatal conductance, photosynthesis rate and internal CO2 concentration with increased shading. Shading decreased the concentration of chlorophyll a while promoting an increase in chlorophyll b and total chlorophyll, with no significant difference between the levels of 50% and 70% of shading. The shaded environments provided greater growth in height, diameter, leaf area, in addition to providing greater accumulation of dry mass and IQD. It is recommended to produce seedlings of M. rigida seedlings, during the nursery phase, under 50% shading, as this condition provides the achievement of better seedling quality indexes.

MORPHOPHYSIOLOGICAL AND NUTRITIONAL BEHAVIOR OF Hymenaea stigonocarpa Mart. ex Hayne (FABACEAE) SEEDLINGS SUBMITTED TO LIMING

ABSTRACT Liming is beneficial for plants as it promotes pH elevation, neutralization of toxic aluminum, increase in calcium (Ca²+) and magnesium (Mg²+) supply, and provides greater root systems. However, it is known that different species, mainly those native to the Cerrado, respond in different ways to this technique. Given the above, the objective of this study was to determine how Hymenaea stigonocarpa (“Jatobá-do-Cerrado”) seedlings respond to liming in Dystrophic Red Latosol. The plants were cultivated in four-liter pots, submitted to different base saturation (natural soil, 30, 45, 60 and 75% V) and maintained in a greenhouse. Biometrics, biomass, nutritional content and physiological parameters were evaluated. A difference in Ca²+ and Mg²+ contents between leaves and stems was observed, leading to significant reductions in stomatal conductance, transpiration, internal CO2 concentration and internal and external CO2 concentration ratios, resulting in a reduction of the investment in growth and biomass. Given these results, there is no need for liming in the production of H. stigonocarpa seedlings in a Dystrophic Red Latosol.

IRRIGAÇÃO LATERALMENTE ALTERNADA EM LIMA ÁCIDA 'TAHITI' NA REGIÃO NORTE DE MINAS GERAIS

IRRIGAÇÃO LATERALMENTE ALTERNADA EM LIMA ÁCIDA 'TAHITI' NA REGIÃO NORTE DE MINAS GERAIS MARCELO ROCHA DOS SANTOS1; SÉRGIO LUIZ RODRIGUES DONATO1; EUGÊNIO FERREIRA COELHO2; ALESSANDRO DE MAGALHÃES ARANTES1 E MAURÍCIO ANTÔNIO COELHO FILHO2 [1]Instituto Federal Baiano - Campus Guanambi, Distrito de Ceraíma, Caixa Postal 009, CEP 46.430-000, [email protected], [email protected], [email protected] Mandioca e Fruticultura, Rua Embrapa s/n, Caixa Postal 007, CEP 44380-000, Cruz das Almas, BA, [email protected], [email protected] 1 RESUMO As condições hídricas do solo e clima alteram as condições hídricas e fisiológicas das plantas, que influenciam o desenvolvimento e a produção. Objetivou-se com este estudo avaliar características fisiológicas, estado nutricional e produtividade em lima ácida 'Tahiti' com irrigação lateralmente alternada (partial rootzone drying – PRD). Nove tratamentos foram constituídos por diferentes reposições de lâmina de água aplicada, conforme a demanda evapotranspirométrica da cultura (ETc) e diferentes frequências de alternância no período compreendido entre a floração e a colheita, em dois ciclos produtivos da cultura, dispostos em delineamento em blocos casualizados com quatro repetições. O sistema de irrigação utilizado foi por gotejamento com duas linhas laterais e doze gotejadores por planta. Dos nutrientes analisados ficaram abaixo da faixa de suficiência apenas o teor de B nas plantas sob PRD a 50% da ETc e frequência de alternância (FA) de 7 dias, e de B e Mn sob PRD a 50% da ETc e FA de 21 dias e PRD a 75% da ETc e FA de 14 dias. Fotossíntese, transpiração, condutância estomática, concentração interna de CO2, radiação fotossinteticamente ativa e temperatura foliar variaram com a época e o horário de mensuração. Eficiência de carboxilação, eficiência quântica da fotossíntese e eficiência instantânea de uso da água (EUA) são maximizadas nos meses e horas dos dias com menores temperaturas. A PRD altera a concentração interna de CO2, transpiração, razão de carboxilação, razão de concentração de CO2 e produtividade. Há manutenção da produtividade com irrigação alternada a cada sete dias e PRD de 50% da ETc em relação à irrigação plena. Palavras-chave: Citrus, manejo da irrigação, déficit hídrico. SANTOS, M. R.; DONATO, S. L. R; COELHO, E. F.; ARANTES, A. M.; COELHO FILHO, M. A.PARTIAL ROOTZONE DRYING IN ACID LIME 'TAHITI' IN NORTHERN OF MINAS GERAIS BRAZIL 2 ABSTRACT The water conditions of the soil and climate change the water and physiological conditions of plants, influencing their development and production. This study aimed to evaluate gas exchanges, leaf temperature, nutrient levels in leaves and yield in acid lime ‘Tahiti’ under partial rootzone drying (PRD). Nine treatments were used with different percentages of crop evapotranspiration and different frequencies of alternation, from the beginning of flowering to physiological mature fruits in two productive cycles, arranged in a randomized block design with four replicates. The irrigation system was dripped with two lateral lines per row of plants, with twelve emitters per plant. Only the concentration of B was insufficient in plants under PRD with 50% ETc and frequency of alternation (FA) 7 days, PRD with 50% ETc and FA 21 days PRD and 75% ETc and FA 14 days and Mn for PRD 50% of ETc FA and 21 days PRD and 75% of ETc and FA 14 days. Photosynthesis, transpiration, stomatal conductance, internal CO2 concentration, photosynthetically active radiation and leaf temperature in Tahiti lime parameters are influenced by the period and time of measurement. The carboxylation efficiency, quantum efficiency of photosynthesis and instantaneous water use efficiency is maximized in the months and hours of days with lower temperatures. The PRD causes changes in internal CO2 concentration, transpiration, rate of carboxylation, ratio of CO2 concentration and yield. The highest yield occurred for PRD with 50% of ETc alternating irrigation every seven days in relation to full irrigation. Keyword: Citrus, irrigation management, water deficit.

Determination of damaged leaf area and physiological responses of melon plants submitted to different infestation levels of Liriomyza sativae

ABSTRACT The leafminer Liriomyza sativae (Diptera: Agromyzidae) is one of the main pests of melon crop (Cucumis melo) in the Brazilian semiarid. The aims of this study were to determine the damaged leaf area and assess the physiological responses of melon plants submitted to different levels of infestation per larvae of L. sativae. The study was carried out in a greenhouse, using plants of melon of the cultivar Iracema (yellow melon). The design utilized was completely randomized, with five treatments {control (no infestation in the leaves) and four infestation levels (1; 10; 20 and 30 larvae per leaf)} and 10 replications (melon plants). Initially we evaluated the physiological aspects: photosynthetic rate (µmol CO2/m2/s), stomatal conductance (mol H2O/m2/s) internal CO2 concentration (µmol CO2/m2) and leaf transpiration (mmol H2O/m2/s). After the measurements of physiological aspects, the evaluated leaves of each plant were cut close to the petiole and scanned individually with a measuring scale on the side, being the determination of the damaged leaf area performed with the aid of software for processing and analysis of images. The averages of damaged leaf area observed were of 1.2; 6.3; 19.6 and 40.8 cm2 for infestations of 1; 10; 20 and 30 larvae/leaf respectively. In relation to the physiological aspects, the rate of photosynthesis, stomatal conductance and transpiration significantly decreased with the increase of leafminer larvae per leaf. The internal CO2 concentration increased with the increase in the number of larvae per leaf.