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

2017 ◽  
Vol 35 (4) ◽  
pp. 571-575 ◽  
Author(s):  
Ewerton M Costa ◽  
Rômulo Magno O Freitas ◽  
Paolo Augustus F Silva ◽  
Elton Lucio Araujo
Keyword(s):  
Stomatal Conductance ◽  
Leaf Area ◽  
Physiological Responses ◽  
Co2 Concentration ◽  
Internal Co2 Concentration ◽  
Liriomyza Sativae ◽  
Leaf Transpiration ◽  
Rate Of Photosynthesis ◽  
Internal Co2

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.

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

2021 ◽  
Vol 39 (1) ◽  
pp. 65-71
Author(s):  
Italo MG Sampaio ◽  
Mário L Silva Júnior ◽  
Ricardo FPM Bittencourt ◽  
Gabriel AM dos Santos ◽  
Fiama KM Nunes ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Leaf Area ◽  
Nutrient Solution ◽  
Co2 Concentration ◽  
Dry Mass ◽  
Ionic Concentration ◽  
Stem Diameter ◽  
Internal Co2 Concentration ◽  
Internal Co2 ◽  
Fresh And Dry Mass

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.

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

2020 ◽  
Vol 9 (7) ◽  
pp. e878974508
Author(s):  
Roberta Patrícia de Sousa Silva ◽  
Antonio Lucineudo de Oliveira Freire ◽  
Ivonete Alves Bakke ◽  
Cheila Deisy Ferreira ◽  
Sérvio Túlio Pereira Justino ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Leaf Area ◽  
Weight Ratio ◽  
Co2 Concentration ◽  
Dry Mass ◽  
Photosynthesis Rate ◽  
Chlorophyll Contents ◽  
Internal Co2 Concentration ◽  
Significant Difference ◽  
Internal Co2

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.

scholarly journals Interaction between soil salinity and nitrogen on growth and gaseous exchanges in guava

2018 ◽  
Vol 13 (3) ◽  
pp. 1
Author(s):  
Idelfonso Leandro Bezerra ◽  
Hans Raj Gheyi ◽  
Reginaldo Gomes Nobre ◽  
Geovani Soares de Lima ◽  
João Batista dos Santos ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Leaf Area ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Stem Diameter ◽  
Assimilation Rate ◽  
Gas Exchanges ◽  
Internal Co2 ◽  
N Dose ◽  
Number Of Leaves

This study evaluated the growth and gas exchanges of guava, cv. ‘Paluma’ cultivated in salinized soil and subjected to different nitrogen (N) doses in a protected environment in the municipality of Campina Grande-PB. The experimental design was randomized blocks, in a 5 x 4 factorial arrangement with three replicates, and the treatments resulted from the combination of five salinity levels in the soil saturation extract - ECse (2.15, 3.15,4.15, 5.15 and 6.15 dS m-1) and four N doses (70, 100, 130 and 160% of the recommended N dose). The dose referring to 100% of N corresponded to 541.1 mg of N dm-3 of soil. At 120 and 180 days after (DAT), plant growth was evaluated based on stem diameter (SD), leaf area (LA) and number of leaves (NL). At 210 DAT, the following variables of leaf gas exchanges were evaluated: stomatal conductance (gs), internal CO2 concentration (Ci), transpiration (E) and CO2 assimilation rate (A). ECse above 2.15 dS m-1 reduced stem diameter, leaf area, number of leaves, stomatal conductance, internal CO2 concentration, transpiration and CO2 assimilation rate, in both evaluation periods. N dose above 70% of the recommendation (378.7 mg N dm-3 of soil) did not mitigate the deleterious effects caused by the salt stress on the growth and gas exchanges of guava plants.

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

2019 ◽  
Vol 43 (3) ◽  
Author(s):  
Patrícia Oliveira da Silva ◽  
Leandro Carlos ◽  
Paulo Eduardo Menezes-Silva ◽  
Andréia Mendes da Costa ◽  
Carlos Ribeiro Rodrigues ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Co2 Concentration ◽  
Root Systems ◽  
Base Saturation ◽  
Natural Soil ◽  
Nutritional Content ◽  
Internal Co2 Concentration ◽  
Internal Co2 ◽  
Red Latosol ◽  
Ph Elevation

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.

Different Light Radiation Intensities on Cotton: A Physiological Approach

2019 ◽  
pp. 1-8
Author(s):  
Lucas Aparecido Manzani Lisboa ◽  
Fernando Takayuki Nakayama ◽  
Edivaldo Cia ◽  
Paulo Alexandre Monteiro de Figueiredo ◽  
Sérgio Bispo Ramos ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Block Design ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Luminous Intensity ◽  
Artificial Light ◽  
Light Intensities ◽  
Leaf Transpiration ◽  
Randomized Complete Block Design ◽  
Physiological Approach

The luminosity and the temperature are factors that act directly in the photosynthetic process, where an elevation of the luminous intensity can cause a reduction of the assimilation of carbon, which consequently lowers the development of the cotton. The objective of this work was to assess the response of physiological parameters of cotton when subjected to different artificial light intensities. Two varieties of cotton IMA5801B2RF and IACRDN, were interacting with five artificial light intensities: 0 (control); 500; 1000; 1500 and 2000 μmol m−2 s−1 of photosynthetically active radiation provided by LED bulbs. The experiment was set in a randomized complete block design using a 2x5 factorial scheme. The variables measured were the rate of CO2 assimilation, transpiration, stomatal conductance, inner CO2 concentration in the substomatic chamber, and efficient use of water (for which a portable device of gas exchange was used). The cotton varieties responded positively to different luminous intensities until reaching the point of maximum saturation between 1400 and 1600 µmol m-1 s-1 of light, which provided a better rate of CO2 assimilation, concentration of CO2 in the substomatic chamber, and efficient use of water. Leaf transpiration and stomatal conductance showed a positive linear response with increasing light intensity. The ideal luminous intensity for the use of Infra-Red Gas Analyzer - IRGA was 1500 µmol m-1 s-1 for the tested cotton varieties.

The interplay between irrigation and fruiting on branch growth and mortality, gas exchange and water relations of coffee trees

2020 ◽  
Author(s):  
Wellington L Almeida ◽  
Rodrigo T Ávila ◽  
Junior P Pérez-Molina ◽  
Marcela L Barbosa ◽  
Dinorah M S Marçal ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Stomatal Density ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Co2 Concentration ◽  
Plant Hydraulics ◽  
Branch Growth ◽  
Source To Sink ◽  
Leaf Transpiration

Abstract The overall coordination between gas exchanges and plant hydraulics may be affected by soil water availability and source-to-sink relationships. Here we evaluated how branch growth and mortality, leaf gas exchange and metabolism are affected in coffee (Coffea arabica L.) trees by drought and fruiting. Field-grown plants were irrigated or not, and maintained with full or no fruit load. Under mild water deficit, irrigation per se did not significantly impact growth but markedly reduced branch mortality in fruiting trees, despite similar leaf assimilate pools and water status. Fruiting increased net photosynthetic rate in parallel with an enhanced stomatal conductance, particularly in irrigated plants. Mesophyll conductance and maximum RuBisCO carboxylation rate remained unchanged across treatments. The increased stomatal conductance in fruiting trees over nonfruiting ones was unrelated to internal CO2 concentration, foliar abscisic acid (ABA) levels or differential ABA sensitivity. However, stomatal conductance was associated with higher stomatal density, lower stomatal sensitivity to vapor pressure deficit, and higher leaf hydraulic conductance and capacitance. Increased leaf transpiration rate in fruiting trees was supported by coordinated alterations in plant hydraulics, which explained the maintenance of plant water status. Finally, by preventing branch mortality, irrigation can mitigate biennial production fluctuations and improve the sustainability of coffee plantations.

scholarly journals Effect of fertigation with potassium and nitrogen on gas exchange and biomass accumulation in eggplant1

2017 ◽  
Vol 47 (3) ◽  
pp. 345-352
Author(s):  
Álvaro Henrique Cândido de Souza ◽  
Roberto Rezende ◽  
Marcelo Zolin Lorenzoni ◽  
Fernando André Silva Santos ◽  
André Maller
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Use ◽  
Biomass Accumulation ◽  
Net Photosynthesis ◽  
Dry Weight ◽  
Co2 Concentration ◽  
Internal Co2 ◽  
Use Efficiency ◽  
Total Dry Weight

ABSTRACT Adequate crop fertilization is one of the challenges for agriculture. Measuring gas exchange and biomass accumulation may be used to adjust crop management. The effect of fertigation with potassium (0 kg ha-1, 54 kg ha-1, 108 kg ha-1 and 216 kg ha-1) and nitrogen (0 kg ha-1, 67 kg ha-1, 134 kg ha-1 and 268 kg ha-1) on gas exchange and biomass accumulation in eggplant was assessed under greenhouse conditions. The net photosynthesis, stomatal conductance, transpiration, internal CO2 concentration, instantaneous carboxylation efficiency, water-use efficiency and total dry weight were evaluated. With the exception of K for water-use efficiency and N for internal CO2 concentration, all the other gas exchange parameters were significantly affected by the K and N doses. There was an interaction between N and K doses for net photosynthesis, stomatal conductance, transpiration and instantaneous carboxylation efficiency. The highest values for net photosynthesis, stomatal conductance, transpiration rate, carboxylation instantaneous efficiency and total dry weight were found in the range of 125-185 kg ha-1 of K and 215-268 kg ha-1 of N.

scholarly journals Effect of Biostimulants on Several Physiological Characteristics and Chlorophyll Content in Broccoli under Drought Stress and Re-watering

2017 ◽  
Vol 45 (1) ◽  
pp. 197-202 ◽  
Author(s):  
Alina KAŁUŻEWICZ ◽  
Włodzimierz KRZESIŃSKI ◽  
Tomasz SPIŻEWSKI ◽  
Anna ZAWORSKA
Keyword(s):  
Amino Acids ◽  
Drought Stress ◽  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
Transpiration Rate ◽  
Co2 Concentration ◽  
Ascophyllum Nodosum ◽  
Internal Co2 ◽  
The Many ◽  
Final Effect

Drought stress is one of the many factors that lead to decreased yield in both quality and quantity. One method to improve plant resistance to this stress is application of biostimulants. The most widely used biostimulants are protein hydrolysates, containing sea algae extract and humus compounds. In the present study, the influence of the amino acids as well as combination of amino acids with Ascophyllum nodosum filtrate on broccoli (Brassica oleracea var. italica) plants cvs. ‘Agassi’ and ‘Tiburon’ was investigated. The plants were watered with Ascophyllum nodosum filtrate three days before planting and sprayed three times with amino acids two, four and six weeks after planting. The present results show that biostimulants have a significant effect on both gas exchange and transpiration rate both prior to the application of stress, under drought stress and after re-watering. Biostimulant treatment led to an increase of drought tolerance in both studied cultivars but the final effect depended on cultivar. ‘Tiburon’ cultivar turned out to be more tolerant to drought stress than ‘Agassi’. The application of biostimulants resulted in an increase of photosynthetic rate, stomatal conductance, internal CO2 concentration and transpiration rate in ‘Agassi’ cultivar under drought stress. This effect was not observed in ‘Tiburon’. The chlorophyll content was higher under drought stress as compared to the value prior to stress in both cultivars.

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