scholarly journals Organization of leaf vascular system and gas exchange in seedlings of Guazuma ulmifolia Lam. in different light conditions

2021 ◽  
Vol 14 (7) ◽  
pp. 68-73
Author(s):  
Marcus Vinicius de Lima Costa ◽  
Pedro Antônio de Lima Félis ◽  
Kelvin Jean Santos Masselani ◽  
Túlio Lopes Marinho Linard ◽  
Luis Alberto Bucci ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Vascular System ◽  
Light Conditions ◽  
Abaxial Epidermis ◽  
Full Sunlight ◽  
Adaxial Epidermis ◽  
Guazuma Ulmifolia

In tropical forests, different physiological characteristics of leaves in tree species are evidenced by variations in different incident light conditions. We aim to evaluate gas exchange and organization of leaf vascular system in Guazuma ulmifolia Lam. seedlings under different light conditions. Seedlings were obtained from seeds germinated under greenhouse conditions with controlled environment. Ninety days after germination, seedlings in 8kg pots were transferred to the experimental site to allow acclimatization under sun and shade conditions. The experimental design was completely randomized, with two treatments: full sunlight and artificial shading, limiting the luminosity to about 5% of irradiance. Seedlings were maintained under these conditions for 120 days before measuring gas exchange parameters. We measured photosynthetic rate, stomatal conductance, sub-stomatic CO2 concentration, transpiration, and chlorophyll content. Anatomical analysis measured distance between veins, distance from veins to abaxial epidermis, distance from veins to adaxial epidermis, distance from veins to stomata, total leaf thickness, abaxial epidermis thickness, adaxial epidermis thickness, palisade parenchyma thickness, and spongy parenchyma thickness of foliar gas exchange of G. ulmifolia which presented significant differences between light environments. Photosynthetic rate and stomatal conductance were reduced by 78% and 39%, respectively, in shade, while stomatal conductance increased by 31% in full sunlight. Transpiration showed no significant difference between the two treatments, but chlorophyll content was 30% lower in full sunlight. Distance between veins and distance from veins to stomata showed no difference between treatments, but the other parameters increased in full sunlight. Thus, the results showed that the pioneer species G. ulmifolia presented leaf gas exchange acclimated to environments with high luminosity.

scholarly journals Effect of Soil Applied Silicon on Gas Exchange Parameters, Growth and Ion Content of Maize under Alkaline Stress

2021 ◽  
Vol 12 (1) ◽  
pp. 032-039
Author(s):  
Gokula Priya Natarajan ◽  
◽  
Malayappa Venkataraman Sriramachandrasekharan ◽  
Rengarjan Manivannan ◽  
Muthu Arjuna Samy Prakash ◽  
...  
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Root Length ◽  
Alkaline Stress ◽  
Ion Content ◽  
Gas Exchange Parameters ◽  
Exchange Parameters

A pot experiment was conducted to understand the effect of soil applied silicon on maize crop growth under alkaline stress. The treatment consists of silicon levels (kg ha-1) – 0, 100 and 150 and alkaline stress levels (mM) – 0, 25, 50, 75. The pots were arranged in completely randomized block design in factorial arrangement with three replications. The result revealed that the shoot and root length and chlorophyll content of maize were reduced with increasing alkaline stress. The percent reduction due to alkaline stress on shoot and root length was to tune of 3.6 to 15.8 and 8.9 to 35.8, respectively and chlorophyll content 11.2 to 35.7. The sodium ion content increased, but potassium content and K Na-1 ratio decreased with alkaline stress. The gas exchange parameters viz., photosynthetic rate, stomatal conductance and transpiration rate were significantly decreased with alkalinity levels. The adverse effect of alkalinity on maize was turnround with intervention of soil applied silicon. The percent increase due to silicon intervention ranged from 4.3 to 12.6 in photosynthetic rate, 4.5 to 14.5 in stomatal conductance, 6.3 to 21.4 in transpiration rate, 7.0 to 20.9 and 8.4 to 29.3 in shoot and root potassium, 19.4 to 33.5 and 20.6 to 55.9 in shoot and root K Na-1. The percent decrease in sodium concentration in shoot and root ranged from 8.6 to 14.2 and 4.3 to 23.7. Between 100 and 150 kgs of silicon applied, the desired result was achieved with 150 kg Si ha-1. It is recommended to apply 150 kg Si ha-1 to maneuver the ill effects of alkalinity on maize.

Effect of Flavone from Forestry Waste C.Cathayensis Exocarp on Photosynthetic Characteristics of Crops

2012 ◽  
Vol 550-553 ◽  
pp. 2365-2368
Author(s):  
Xiang Ming Chen
Keyword(s):  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Transpiration Rate ◽  
Rate Increase ◽  
Co2 Concentration ◽  
Total Chlorophyll ◽  
Photosynthesis Efficiency ◽  
Seedling Leaf ◽  
Intercellular Co2

Using six kinds of concentration (ranged from 0.0 to 2.0mg.L-1) of flavone extract from C.cathayensis exocarp treats corn, soybean, wheat and mung bean seedlings, in order to study the photosynthetic rate, stomatal conductance, transpiration rate, intercellular CO2 on the seedling leaf. Results show that effects of flavone extract (0.1-0.5mg.L-1) increase content of the chlorophyll a, b and total chlorophyll, promote photosynthetic rate, stomatal conductance, transpiration rate, proper increase cell gap inside the CO2 concentration.0.1mg.L-1 treatment effect is the most obvious compare with the control, the total chlorophyll and photosynthetic rate increase by 20.9 % and 21% respectively; More than 0.5mg.L-1, the chlorophyll content, photosynthetic rate, stomatal conductance, transpiration rate decrease, the intercellular CO2 rapid increase. Research shows that, the appropriate concentration of flavone can increase the chlorophyll content in the leaf, promote stomatal opening, increase of intracellular CO2 supply, improve leaf photosynthesis efficiency.

Effect of the soil water content on Jatropha seedlings in a tropical climate

2013 ◽  
Vol 27 (3) ◽  
pp. 351-357 ◽  
Author(s):  
A. Pérez-Vázquez ◽  
G. Hernández-Salinas ◽  
C. Ávila-Reséndiz ◽  
O.A. Valdés-Rodríguez ◽  
F. Gallardo-López ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Stomatal Conductance ◽  
Water Content ◽  
Soil Water ◽  
Chlorophyll Content ◽  
Soil Water Content ◽  
Photosynthetic Rate ◽  
Dry Matter ◽  
Number Of Leaves ◽  
Different Levels

Abstract The purpose of this study was to evaluate growth, chlorophyll content, and photosynthesis in Jatropha at different levels of soil moisture. Plants were cultivated in containers and the treatments of the soil water content evaluated were: 0% (without watering), 20, 40, 60, and 80% soil water content. Plant height was statistically similar for all treatments, but the number of leaves differed significantly. Total dry matter and chlorophyll at 40, 60, and 80% soil water content were statistically similar, but different from 0 and 20% soil water content. Leaf area at 40, 60, and 80% soil water content was statistically different from 0 and 20% soil water content. The photosynthetic rate, transpiration and stomatal conductance at 60 and 80% soil water content were statistically similar but different from 0 and 20% soil water content. Water stress affected growth, chlorophyll content, photosynthetic rate, transpiration, and stomatal conductance.

scholarly journals Effect of drought on gas exchange and chlorophyll fluorescence of groundnut genotypes

2021 ◽  
Vol 13 (4) ◽  
pp. 1478-1487
Author(s):  
K. Manojkumar ◽  
S. Vincent ◽  
M. Raveendran ◽  
R. Anandham ◽  
V. Babu Rajendra Prasad ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Stress ◽  
Stomatal Conductance ◽  
Gas Exchange ◽  
Photosynthetic Rate ◽  
Photosynthetic Activity ◽  
Water Deficit Stress ◽  
Abiotic Factor ◽  
Gas Exchange Parameters ◽  
Ps Ii

Drought is one of the major threats to groundnut productivity, causing a greater loss than any other abiotic factor. Water stress conditions alter plant photosynthetic activity, impacting future growth and assimilating mobilization towards sink tissues. The purpose of this study was to investigate how drought impacts the photosynthesis of plants and its links to drought tolerance. The influence of reproductive stage drought on photosynthetic activity and chlorophyll fluorescence of groundnut is well studied. The experiment was conducted in Kharif 2019 (Jul-Sep), where recent series in groundnut genotypes (60 nos) sown under rainfed conditions and water stress was created by withholding irrigation for 20 days between 35-55 days after sowing in the field to simulate drought conditions. Imposition of water deficit stress reduced PS II efficiency, which significantly altered the photosynthetic rate in the leaf. Observation of gas exchange parameters viz., photosynthetic rate, stomatal conductance and transpiration rate after 20 days of stress imposition revealed that of all 60 genotypes, 20 genotypes (VG 17008, VG 17046VG 18005, VG 18102, VG 18077, VG 19572, VG 19709, VG 18111, VG19561, VG19576, VG 19620, VG 19681, VG 19688, etc.,) had better Photosynthetic rate, Stomatal conductance. Similarly, PS II efficiency analyzed through fluorescence meter revealed that among the 60 and all the genotypes given above recorded higher value in Fv/Fm. Results obtained from Cluster analysis and PCA confirmed that photosynthetic rate and Fv/Fm is useful parameter in screening adapted cultivars under drought stress. These findings lay the groundwork for a future study to decipher the molecular pathways underpinning groundnut drought resistance.

scholarly journals Zinc Deficiency Inhibits Chlorophyll Synthesis and Gas Exchange in `Stuart' Pecan

HortScience ◽  
1991 ◽  
Vol 26 (3) ◽  
pp. 267-268 ◽  
Author(s):  
Hening Hu ◽  
Darrell Sparks
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Chlorophyll Content ◽  
Net Photosynthesis ◽  
Chlorophyll Synthesis ◽  
Zn Deficiency ◽  
Carya Illinoensis ◽  
Physiological Indicators ◽  
Leaf Chlorophyll ◽  
Zn Concentration

Leaves of `Stuart' pecan [Carya illinoensis (Wangenh.) C. Koch] with various levels of Zn deficiency were analyzed for physiological indicators of leaf vigor. Leaf chlorophyll content, stomatal conductance, and net photosynthesis were adversely affected by Zn deficiency. In leaves with severe Zn deficiency, each of these indicators increased 3- to 5-fold with a doubling of leaf Zn concentration, but stabilized as leaf Zn approached the sufficiency range (14 μg·g-1). High intercellular CO2 associated with low net photosynthesis indicates that stomatal aperture was not the cause of the reduction of net photosynthesis under Zn deficiency.

scholarly journals Physiological and Growth Responses of Several Genotypes of Common Purslane (Portulaca oleracea L.) under Mediterranean Semi-arid Conditions

2017 ◽  
Vol 45 (2) ◽  
pp. 569-575 ◽  
Author(s):  
Anestis C. KARKANIS ◽  
Spyridon A. PETROPOULOS
Keyword(s):  
Stomatal Conductance ◽  
Chlorophyll Content ◽  
Plant Height ◽  
Photosynthetic Rate ◽  
Biomass Yield ◽  
Growth Habit ◽  
Portulaca Oleracea ◽  
Common Purslane ◽  
Semi Arid ◽  
Relative Chlorophyll Content

Common purslane (Portulaca oleracea L.) is a drought-tolerant weed cultivated for its fresh leaves and stems. In the present study, a field experiment was conducted to determine plant development and photosynthesis of several common purslane genotypes in a high-density planting system. The experiment was carried out according to randomized complete block design with four replications per treatment. Four local populations and two commercial cultivars of common purslane were studied. During the experiment, plant biomass, plant height, leaf relative chlorophyll content (SPAD values), stomatal conductance (gs) and photosynthetic rate (A) were recorded. From the results of our study significant differences in plant height and biomass were observed among the studied genotypes. The lowest height and biomass were found in genotype ‘Domokos’ whose growth was prostrate to semi-prostrate, whereas all the other genotypes had erect growth. Differences were also observed in physiological parameters. In particular, the relative chlorophyll content (SPAD value) was the highest for genotype ‘Domokos’, whereas stomatal conductance and photosynthetic rates were the lowest for the same genotype. Biomass yield had also positive and significant correlation with photosynthetic rate and plant height. Our results indicate that the tested genotypes had significant differences in growth habit and physiological parameters. Comparing the tested genotypes, it could be suggested that apart from genotype ‘Domokos’ which had lower biomass yield due to its growth habit, the rest of the genotypes could be suitable for commercial purposes and proposed as an alternative crop in semi-arid regions of the Mediterranean basin.

Tolerance of Tomato to Herbicides Applied through Drip Irrigation

2012 ◽  
Vol 26 (4) ◽  
pp. 684-690 ◽  
Author(s):  
Peter J. Dittmar ◽  
David W. Monks ◽  
Katherine M. Jennings ◽  
Fitzgerald L. Booker
Keyword(s):  
Stomatal Conductance ◽  
Linear Relationship ◽  
Chlorophyll Content ◽  
Photosynthetic Rate ◽  
Drip Irrigation ◽  
Field Studies ◽  
Fruit Yield ◽  
Herbicide Application ◽  
Application Method ◽  
Herbicide Treatments

Greenhouse and field studies were conducted to determine tolerance of tomato to halosulfuron, imazosulfuron, and trifloxysulfuron herbicides applied through drip irrigation. In greenhouse studies, PRE- and POST-applied trifloxysulfuron caused greater tomato injury (14 and 54% injury, respectively) than PRE- and POST-applied halosulfuron (5 and 26% injury, respectively) or imazosulfuron (5 and 23% injury, respectively). All herbicide treatments in the greenhouse studies caused greater injury to tomato than the nontreated. Greater tomato injury was observed in the greenhouse from herbicides applied POST than when soil applied. Tomato injury from POST-applied halosulfuron, imazosulfuron, or trifloxysulfuron followed a linear relationship, with tomato injury increasing with increasing herbicide rate. Tomato photosynthetic rate did not differ among the herbicide treatments (32.7 to 55.0 μmol m−2 s−1) and the nontreated (38.0 to 55.0 μmol m−2 s−1). At 5 to 16 days after treatment (DAT), tomato treated with imazosulfuron POST (0.26 to 0.46 cm s−1) or trifloxysulfuron POST (0.27 to 0.51 cm s−1) had lower stomatal conductance compared to the stomatal conductance of the nontreated tomato (0.65 to 0.76 cm s−1). Chlorophyll content did not differ among treatments at 0 to 6 DAT. At 7 to 12 DAT, tomato treated with imazosulfuron POST (34.0 to 40.1 SPAD) and trifloxysulfuron POST (35.0 to 41.6 SPAD) had lower chlorophyll content compared to the nontreated (39.1 to 48.1 SPAD). In 2008 and 2009 field studies, no tomato injury was observed. Herbicide, herbicide application method, and herbicide rate had no effect on tomato height (73 to 77 cm 14 DAT, 79 to 84 cm 21 DAT) and total fruit yield (62,722 to 80,328 kg ha−1).

Gas exchange and yield in Miscanthus species for three years at two locations in Poland

2013 ◽  
Vol 93 (4) ◽  
pp. 627-637 ◽  
Author(s):  
Katarzyna Głowacka ◽  
Stanisław Jeżowski ◽  
Zygmunt Kaczmarek
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Photosynthetic Rate ◽  
Correlation Coefficients ◽  
Regression Analyses ◽  
Gas Exchange Parameters ◽  
The Third ◽  
Intrinsic Water Use Efficiency ◽  
Use Efficiency ◽  
Exchange Parameters

Głowacka, K., Jeżowski, S. and Kaczmarek, Z. 2013. Gas exchange and yield in Miscanthus species for three years at two locations in Poland. Can. J. Plant Sci. 93: 627–637. The influence of gas exchange parameters on yields of six Miscanthus clones were evaluated in two locations over three years. Five out of six genotypes had significant increases in the photosynthetic rate and intrinsic water use efficiency between the third and first or third and second years, while intercellular CO2 concentration and stomatal conductance decreased. In addition, the multiple regression analyses of yields on parameters showed that the type of the correlation coefficients for transpiration, stomatal conductance and intercellular CO2 concentration varied throughout the years. The strongest correlation (0.86) between yield and photosynthetic rate was found for 3-year-old plants.

scholarly journals Gas Exchange and Chlorophyll Content of `Tifblue' Rabbiteye and `Sharpblue' Southern Highbush Blueberry Exposed to Salinity and Supplemental Calcium

1993 ◽  
Vol 118 (4) ◽  
pp. 456-463 ◽  
Author(s):  
Glenn C. Wright ◽  
Kim D. Patten ◽  
Malcolm C. Drew
Keyword(s):  
Stomatal Conductance ◽  
Gas Exchange ◽  
Chlorophyll Content ◽  
Sand Culture ◽  
Highbush Blueberry ◽  
Leaf Chlorophyll Content ◽  
Leaf Chlorophyll ◽  
Leaf Necrosis ◽  
Net Assimilation ◽  
Southern Highbush

`Tifblue' rabbiteye blueberry (Vaccinium ashei Reade) and `Sharpblue' southern highbush blueberry (primarily V. corymbosum) were treated with 0, 25, or 100 Mm Na+ as Na2SO4 or NaC1, and 0, 1, 3, or 10 Mm supplemental Ca2+ in sand culture in the greenhouse. Greatest stomatal conductance (gs) and net assimilation (A) occurred in unsalinized `Tifblue' plants not given additional Ca2+. Stomatal conductance, A, transpiration (E), and xylem water potential(Ψ)of `Tifblue' and `Sharpblue' plants were all lowered as salinity increased, and these effects were more pronounced with NaCl than with Na2SO4. After 63 days, for plants given 100 Mm Na+ as NaCl, gs and net assimilation rate were reduced to only 10% of the unsalinized controls, while for plants salinized with 100 mm Na+ as Na2SO4, gs and A were 35% and 43%, respectively, of unsalinized controls. Leaf necrosis was more extensive on `Sharpblue' plants given NaCl than on `Tifblue' plants. Neither Ca2+ nor Na+ treatments led to severe chlorosis; reductions in leaf chlorophyll content were mainly due to necrosis. The Na+- induced reduction in gas exchange was associated with negative Ψw Ca2+ deficiency, or a combination of these factors. Additional factors leading to inhibition of gas exchange in NaCl- stressed plants include Cl- toxicity and leaf necrosis. Calcium supplements were unable to ameliorate NaCl damage in `Tifblue' or `Sharpblue' plants, possibly because of the inability of Ca2+ to counter Cl- entry and toxicity. In contrast, additional Ca2+ improved gs, A, Ψw, and leaf chlorophyll content of `Tifblue' plants that received Na2SO4. For plants treated with 25 mm Na+ as Na2SO4 and 1 mm Ca2+, gs was 1.5 to 2.5 times higher than in plants without added Ca2+. Low (1 mm) concentrations of Ca2+ were more effective in ameliorating the effects of 100 mm Na+ as Na2SO4. than were 3 or 10 mm Ca2+ supplements, possibly because higher Ca2+ concentrations damaged the metabolism of the calcifuge blueberry.

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