scholarly journals Ultra-diluted Solutions of Nux vomica in the Remediation of Metals in Soils and Bioavailability for Soybeans

2019 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Affonso C. Gonçalves Jr. ◽  
Daniel Schwantes ◽  
Andreia P. Schiller ◽  
Jéssica Manfrin ◽  
Juliano Zimmermann ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Co2 Assimilation ◽  
Nutrient Composition ◽  
Stem Diameter ◽  
Distilled Water ◽  
Homeopathic Remedy ◽  
Homeopathic Medicine ◽  
Soybean Plants ◽  
Component Production

The aim of this study was to evaluate the homeopathic medicine Nux vomica in the remediation of soils contaminated with cadmium (Cd) and lead (Pb) and the bioavailability of these metals in soybean plants. To this end the soil was contaminated prior to sowing, using CdCl2H2O and PbCl2 salts in three rates, based on the resolution of the research values of resolution No. 420 of CONAMA, resulting in 0.0, 3.0 and 9.0 mg kg-1 for Cd and 89.0, 180.0 and 540.0 mg kg-1 for Pb. The homeopathic remedy Nux vomica was used in dynamizations 12, 24, 48, 96, 200 and 400 CH (Centesimal Hanhemannian), being the witness with distilled water. Medicines were applied to the soil seven days before sowing and after sowing, every 14 days applied in the plant until complete the cycle. During cultivation were evaluated development, gas exchange, nutrient composition, component production and bioavailability of metals in the plant. The results demonstrate that Nux vomica medicine interfered in height and stem diameter and CO2 assimilation, stomatal conductance and transpiration of soybean plants, but did not affect the bioavailability of metals to plants.

Shade tree species affect gas exchange and hydraulic conductivity of cacao cultivars in an agroforestry system

2020 ◽  
Author(s):  
Eleinis Ávila-Lovera ◽  
Héctor Blanco ◽  
Olga Móvil ◽  
Louis S Santiago ◽  
Wilmer Tezara
Keyword(s):  
Hydraulic Conductivity ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Co2 Assimilation ◽  
Agroforestry System ◽  
Timber Species ◽  
Positive Contribution ◽  
Assimilation Rate ◽  
Co2 Assimilation Rate ◽  
Carbon Economy

Abstract Shade tolerance is a widespread strategy of rainforest understory plants. Many understory species have green young stems that may assimilate CO2 and contribute to whole-plant carbon balance. Cacao commonly grows in the shaded understory and recent emphasis has been placed on diversifying the types of trees used to shade cacao plants to achieve additional ecosystem services. We studied three agricultural cacao cultivars growing in the shade of four timber species (Cedrela odorata L., Cordia thaisiana Agostini, Swietenia macrophylla King and Tabebuia rosea (Bertol) A.D.C.) in an agroforestry system to (i) evaluate the timber species for their effect on the physiological performance of three cacao cultivars; (ii) assess the role of green stems on the carbon economy of cacao; and (iii) examine coordination between stem hydraulic conductivity and stem photosynthesis in cacao. Green young stem photosynthetic CO2 assimilation rate was positive and double leaf CO2 assimilation rate, indicating a positive contribution of green stems to the carbon economy of cacao; however, green stem area is smaller than leaf area and its relative contribution is low. Timber species showed a significant effect on leaf gas exchange traits and on stomatal conductance of cacao, and stem water-use efficiency varied among cultivars. There were no significant differences in leaf-specific hydraulic conductivity among cacao cultivars, but sapwood-specific hydraulic conductivity varied significantly among cultivars and there was an interactive effect of cacao cultivar × timber species. Hydraulic efficiency was coordinated with stem-stomatal conductance, but not with leaf-stomatal conductance or any measure of photosynthesis. We conclude that different shade regimes determined by timber species and the interaction with cacao cultivar had an important effect on most of the physiological traits and growth variables of three cacao cultivars growing in an agroforestry system. Results suggested that C. odorata is the best timber species to provide partial shade for cacao cultivars in the Barlovento region in Venezuela, regardless of cultivar origin.

Water transport from stem to stomata: the coordination of hydraulic and gas exchange traits across 33 subtropical woody species

2019 ◽  
Vol 39 (10) ◽  
pp. 1665-1674 ◽  
Author(s):  
Xiaorong Liu ◽  
Hui Liu ◽  
Sean M Gleason ◽  
Guillermo Goldstein ◽  
Shidan Zhu ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Water Transport ◽  
Explanatory Power ◽  
Woody Species ◽  
Hydraulic Conductance ◽  
Co2 Assimilation ◽  
Leaf Hydraulic Conductance ◽  
Net Co2 Assimilation ◽  
Leaf Tissues

Abstract Coordination between sapwood-specific hydraulic conductivity (Ks) and stomatal conductance (gs) has been identified in previous studies; however, coordination between leaf hydraulic conductance (Kleaf) and gs, as well as between Kleaf and Ks is not always consistent. This suggests that there is a need to improve our understanding of the coordination among hydraulic and gas exchange traits. In this study, hydraulic traits (e.g., Ks and Kleaf) and gas exchange traits, including gs, transpiration (E) and net CO2 assimilation (Aarea), were measured across 33 co-occurring subtropical woody species. Kleaf was divided into two components: leaf hydraulic conductance inside the xylem (Kleaf-x) and outside the xylem (Kleaf-ox). We found that both Kleaf-x and Kleaf-ox were coordinated with gs and E, but the correlations between Kleaf-ox and gs (or E) were substantially weaker, and that Ks was coordinated with Kleaf-x, but not with Kleaf-ox. In addition, we found that Ks, Kleaf-x and Kleaf-ox together explained 63% of the variation in gs and 42% of the variation in Aarea across species, with Ks contributing the largest proportion of explanatory power, whereas Kleaf-ox contributed the least explanatory power. Our results demonstrate that the coordination between leaf water transport and gas exchange, as well as the hydraulic linkage between leaf and stem, were weakened by Kleaf-ox. This highlights the possibility that water transport efficiencies of stem and leaf xylem, rather than that of leaf tissues outside the xylem, are important determinants of stomatal conductance and photosynthetic capacity across species.

Extension of a Farquhar model for limitations of leaf photosynthesis induced by light environment, phenology and leaf age in grapevines (Vitis vinifera L. cvv. White Riesling and Zinfandel)

2003 ◽  
Vol 30 (6) ◽  
pp. 673 ◽  
Author(s):  
Hans R. Schultz
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vitis Vinifera ◽  
Leaf Age ◽  
Large Data ◽  
Co2 Assimilation ◽  
Vitis Vinifera L ◽  
Model Parameters ◽  
Data Set ◽  
Farquhar Model

Measurements of gas exchange and stomatal conductance were made on potted and field-grown grapevines (Vitis vinifera L.) on leaves from different light environments (sun and shade) at different phenological stages during the season to parameterise the Farquhar model. The model parameters for Rubisco activity (Vcmax), maximum electron transport rate (Jmax), and triose-phosphate utilisation (TPU) were estimated on the basis of a large data set (n = 105) of CO2 assimilation (A) versus internal CO2 pressure (Ci) curves. Leaf age was described with the leaf plastochron index (LPI). Stomatal coupling to photosynthesis was modelled with the Ball–Woodrow–Berry empirical model of stomatal conductance. Mature shade leaves had 35–40% lower values of Vcmax, Jmax and TPU than sun leaves. The difference between leaf types decreased at the end of the season. The ratio Jmax / Vcmax and values of day respiration (Rd) and CO2 compensation point in the absence of mitochondrial respiration (Γ*) varied little during the season and were independent of LPI. Validation of the model with independent diurnal data sets of measurements of gas exchange and stomatal conductance at ambient CO2 concentrations for three days between June and October, covering a large range of environmental conditions, showed good agreement between measured and simulated values.

Carbon Isotope Discrimination measured Concurrently with Gas Exchange to Investigate CO2 Diffusion in Leaves of Higher Plants

1986 ◽  
Vol 13 (2) ◽  
pp. 281 ◽  
Author(s):  
JR Evans ◽  
TD Sharkey ◽  
JA Berry ◽  
GD Farquhar
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Carbon Isotope ◽  
Higher Plants ◽  
Isotope Composition ◽  
Co2 Assimilation ◽  
Carbon Isotope Composition ◽  
C3 Plants ◽  
Isotopic Discrimination ◽  
Co2 Diffusion

Conventional gas-exchange techniques that measure the stomatal conductance and rate of CO2 assimilation of leaves were combined with measurements of the carbon isotope composition of CO2 in air passing over a leaf. Isotopic discrimination during uptake was determined from the difference in the carbon isotope composition of air entering and leaving the leaf chamber. Isotopic discrimination measured over the short term correlated strongly with that determined from combusted leaf material. Environmental conditions were manipulated to alter the relative influences of stomatal conductance and carboxylation on the discrimination of carbon isotopes by intact leaves. With C3 plants, discrimination increased as the gradient in partial pressure of CO2 across the stomata decreased. For C4 plants there was little change in discrimination despite substantial changes in the diffusion gradient across the sto- mata. These results are consistent with, and provide the first direct experimental support for, theoretical equations describing discrimination during photosynthesis. Despite uncertainties about various processes affecting carbon isotope composition, the resistance to the transfer of CO2 from the intercellular airspaces to the sites of carboxylation in the mesophyll chloroplasts was estimated using this technique. For wheat the estimated resistance was 1.2-2.4 m2 s bar mol -1.

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 476 Reducing Midday Irradiance Increases Net CO2 Assimilation in Citrus Leaves

HortScience ◽  
2000 ◽  
Vol 35 (3) ◽  
pp. 476B-476
Author(s):  
John L. Jifon ◽  
Jim Syvertsen
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vapor Pressure ◽  
Beneficial Effect ◽  
Leaf Gas Exchange ◽  
Co2 Assimilation ◽  
High Irradiance ◽  
Air Temperatures ◽  
Net Co2 Assimilation ◽  
Citrus Leaves

Maximum CO2 assimilation rates (ACO2) in citrus are not realized in environments with high irradiance, high temperatures, and high leaf-to-air vapor pressure differences (D). We hypothesized that moderate shading would reduce leaf temperature and D, thereby increasing stomatal conductance (gs) and ACO2. A 61% reduction in irradiance under aluminum net shade screens reduced midday leaf temperatures by 8 °C and D by 62%. This effect was prominent on clear days when average midday air temperature and vapor pressure deficits exceeded 30 °C and 3 kPa. ACO2 and gs increased 42% and 104%, respectively, in response to shading. Although shaded leaves had higher gs, their transpiration rates were only 7% higher and not significantly different from sunlit leaves. Leaf water use efficiency (WUE) was significantly improved in shaded leaves (39%) compared to sunlit leaves due to the increase in ACO2. Early in the morning and late afternoon when irradiance and air temperatures were low, shading had no beneficial effect on ACO2 or other gas exchange characteristics. On cloudy days or when the maximum daytime temperature and atmospheric vapor pressure deficits were less than 30 °C and 2 kPa, respectively, shading had little effect on leaf gas exchange properties. The results are consistent with the hypothesis that the beneficial effect of radiation load reduction on ACO2 is related to improved stomatal conductance in response to lowered D.

Effects of container size and fruit load intensity on tomato under salt stress

2021 ◽  
Author(s):  
Kaining Zhou ◽  
Naftali Lazarovitch ◽  
Jhonathan Ephrath
Keyword(s):  
Salt Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Plant Growth ◽  
Plant Height ◽  
Stem Diameter ◽  
Rooting Depth ◽  
Assimilation Rate ◽  
Load Intensity ◽  
Fruit Load

<p>Container size and fruit load intensity are two common factors manipulated to regulate plant growth and development. As saline water is increasingly used for irrigation in arid and semi-arid regions, it is important to study effects of container size and fruit load intensity on tomato in both aboveground and belowground parts under salt stress. The experiment was conducted in a net house located in Sede Boqer Campus, Israel. Containers of four sizes (8-, 28-, 48-, and 200L with the same depth but vary in diameters), two salinity levels (1.5- and 7.5 dS m<sup>−1</sup>) and two crop load intensities (0% and 100%) were applied. Gas exchange parameters (i.e., stomatal conductance and CO<sub>2 </sub>assimilation rate), plant growth parameters (i.e., plant height and stem diameter), and root development were monitored periodically. Plant biomass and various root traits were measured at harvest. For aboveground part, results revealed that container size and salinity level significantly influenced gas exchange performance while fruit load intensity had no significant effect. Plants grown in larger containers without salt stress had higher stomatal conductance and CO<sub>2 </sub>assimilation rate. Plant height and stem diameter were significantly greater in plants grown in 200L than those in other containers despite salinity and fruit load levels. Moreover, plants grown in 200L containers exhibited significant increase of 56.3%, 152.9%, and 174.9% respectively in yield compared with those grown in 48-, 28- and 8L under salt stress. The increase magnitudes were greater when there was no salt stress: 109.0%, 430.8%, and 454.0% respectively. For belowground parts, increased container size leads to increased rooting depth. Besides, Minirhizotron data showed that in 200L containers, plants grown under low salinity without fruit developed the greatest total root length. More detailed root data will be presented.  It is concluded that container size has a pronounced effect on physiological behaviours of tomato plants. Therefore, properly increasing container size can alleviate yield reduction under saline irrigation.</p>

scholarly journals Gas exchange of the umbu tree under semi-arid conditions

2004 ◽  
Vol 26 (2) ◽  
pp. 206-208 ◽  
Author(s):  
José Moacir Pinheiro Lima Filho
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Rainy Season ◽  
Exchange Process ◽  
Co2 Concentration ◽  
Co2 Assimilation ◽  
Internal Co2 ◽  
Gas Exchange Process ◽  
Infrared Gas Analyzer ◽  
Dry And Rainy Seasons

A study was carried out at Embrapa Semi-Árido, Petrolina-PE, Brazil, aiming to understand the gas exchange process of the umbu tree (Spondias tuberosa Arr. Cam.) in the dry and rainy seasons. Stomatal conductance, transpiration, photosynthesis and internal CO2 concentration were obtained with a portable infrared gas analyzer (IRGA). During the dry season the umbu tree showed a much lower stomatal conductance early in the morning, as soon as the vapor pressure deficit increased, apparently affecting CO2 assimilation more than transpiration. The highest values were detected around 6:00 am but decreased to the lowest points between 10:00 am and 2:00 pm. During the rainy season, however, stomatal conductance, transpiration and photosynthesis were significantly higher, reaching the highest values between 8:00 and 10:00 am and the lowest around 2:00 pm. It was also observed at 4:00 pm, mainly during the rainy season, an increase on these variables indicating that the umbu tree exhibits a two-picked daily course of gas exchange.

scholarly journals Sources and Doses of Nitrogen Associated with Inoculation with Azospirillum brasilense Modulate Growth and Gas Exchange of Corn in the Brazilian Amazon

2021 ◽  
Vol 26 (02) ◽  
pp. 349-358
Author(s):  
Juscelino Gonçalves Palheta
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Vegetative Growth ◽  
Azospirillum Brasilense ◽  
Dry Mass ◽  
N Fertilization ◽  
Stem Diameter ◽  
Urease Inhibitor ◽  
Chl A ◽  
Specific Objective

The specific objective of the study was to evaluate effect of inoculation with Azospirillum brasilense and nitrogen (N) doses on vegetative growth and gas exchange in Zea mays L. The experimental design adopted was the completely randomized, in a 4 2 2 factorial scheme, in the following way: four doses of N (0 60 120 and 180 kg ha-1 of N), two sources of N (common urea and urease inhibitor-treated urea) and absence and presence of inoculation with A. brasilense, with four replications. The evaluations were made for vegetative growth of the plant (plant height, stem diameter, leaf area, number of leaves, dry mass of stem, root, leaves and aerial part and total dry mass) and photosynthesis, stomatal conductance, transpiration, internal carbon, relationship between internal and external carbon and content of chloroplast pigments. The application of N provided an improvement in plant growth, and, in general, the dose of 180 kg ha-1 N associated with A. brasilense, promoted an increase in stem diameter, photosynthesis, stomatal conductance, transpiration and internal carbon ratio of the corn. The treatment with urease inhibitor, greatly promoted the stem diameter, transpiration, Ci/Ca ratio and chlorophyll (Chl) a, b, total compared to urea treatment. The inoculation of the corn seeds with the bacteria and the use of N fertilization, regardless of the source, promoted an improvement in the vegetative growth of the hybrid, improving the vegetative growth and the physiological responses of corn when applied to the highest dose of 180 kg/ha N. © 2021 Friends Science Publishers

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