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

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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Arbuscular Mycorrhizal Fungi Inoculation as a Climate Adaptation Strategy for Establishment of Swietenia macrophylla King. Seedlings

Forests ◽

10.3390/f11050488 ◽

2020 ◽

Vol 11 (5) ◽

pp. 488

Author(s):

Lakshmy J. Rajan ◽

Santhoshkumar A. V. ◽

Surendra Gopal K. ◽

Kunhamu T. K.

Keyword(s):

Drought Stress ◽

Stomatal Conductance ◽

Arbuscular Mycorrhizal Fungi ◽

Water Potential ◽

Chlorophyll Content ◽

Transpiration Rate ◽

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizal ◽

Tree Seedlings ◽

Rate Of Photosynthesis

Research Highlights: Drought stress significantly decreased the performance of seedlings in the nursery. Seedlings inoculated with Claroideoglomus etunicatum is recommended to produce superior planting stock of mahogany seedlings with better drought resistance in the nursery. Background and Objectives: With numerous intense droughts across tropical regions due to climate change, it is crucial to understand effects of drought stress on tree seedlings to improve crop management practices and avoid failures on large scale planting. Swietenia macrophylla, a commercial timber species in India, is poorly studied in relation to its management including physiological responses to various environmental stresses. Arbuscular mycorrhizal fungi (AMF) is known to improve performance of tree seedlings under drought conditions and produce quality planting stock in nursery. This study aims to understand the responses of mahogany seedlings under different levels of drought stress when inoculated with three types of AMF, namely Funneliformis mosseae, Claroideoglomus etunicatum, and Rhizophagus intraradices. Materials and Methods: The experiment is conducted in pot culture using a factorial completely randomized design. Different irrigation regimes were applied at 100, 80, 60, and 40 percentage of weekly cumulative evapotranspiration. The seedlings were tested for biometric, physiological, and mycorrhizal parameters periodically. Results: Physiological attributes such as rate of photosynthesis, stomatal conductance, transpiration rate, chlorophyll content, and water potential were found to be higher in the daily irrigated (control) seedlings. Performance of the seedlings were poorest in the least irrigated treatment. It was apparent that inoculated seedlings performed better than the non-inoculated ones. Conclusions: Among the three different AMF species used, C. etunicatum was found to be the most beneficial and suitable for the young mahogany seedlings. These seedlings also recorded higher root colonization percentage and total spore count in the rhizosphere soils. Seedlings inoculated with C. etunicatum showed positive influence on rate of photosynthesis, stomatal conductance, transpiration rate, chlorophyll content, relative growth rate (RGR) and water potential of seedlings.

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

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.550-553.2365 ◽

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.

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The Effects of Drought on Leaf Gas Exchange and Growth of Three Species of Herbaceous Perennials

HortScience ◽

10.21273/hortsci.33.3.540a ◽

1998 ◽

Vol 33 (3) ◽

pp. 540a-540

Author(s):

K.J. Prevete ◽

R.T. Fernandez

Keyword(s):

Drought Stress ◽

Stomatal Conductance ◽

Gas Exchange ◽

Drought Tolerance ◽

Transpiration Rate ◽

Leaf Gas Exchange ◽

Gas Analysis ◽

Herbaceous Perennials ◽

Effects Of Drought ◽

Analysis System

Three species of herbaceous perennials were tested on their ability to withstand and recover from drought stress periods of 2, 4, and 6 days. Eupatorium rugosum and Boltonia asteroides `Snowbank' were chosen because of their reported drought intolerance, while Rudbeckia triloba was chosen based on its reported drought tolerance. Drought stress began on 19 Sept. 1997. Plants were transplanted into the field the day following the end of each stress period. The effects of drought on transpiration rate, stomatal conductance, and net photosynthetic rate were measured during the stress and throughout recovery using an infrared gas analysis system. Leaf gas exchange measurements were taken through recovery until there were no differences between the stressed plants and the control plants. Transpiration, stomatal conductance, and photosynthesis of Rudbeckia and Boltonia were not affected until 4 days after the start of stress. Transpiration of Eupatorium decreased after 3 days of stress. After rewatering, leaf gas exchange of Boltonia and Rudbeckia returned to non-stressed levels quicker than Eupatorium. Growth measurements were taken every other day during stress, and then weekly following transplanting. Measurements were taken until a killing frost that occurred on 3 Nov. There were no differences in the growth between the stressed and non-stressed plants in any of the species. Plants will be monitored throughout the winter, spring, and summer to determine the effects of drought on overwintering capability and regrowth.

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The transcription factor ZmNAC49 reduces stomatal density and improves drought tolerance in maize

Journal of Experimental Botany ◽

10.1093/jxb/eraa507 ◽

2020 ◽

Author(s):

Yang Xiang ◽

Xiujuan Sun ◽

Xiangli Bian ◽

Tianhui Wei ◽

Tong Han ◽

...

Keyword(s):

Transcription Factor ◽

Drought Stress ◽

Stomatal Conductance ◽

Drought Tolerance ◽

Transpiration Rate ◽

Transcriptional Activation ◽

Stomatal Density ◽

Stomatal Development ◽

Expression Of Genes ◽

Growth Development

Abstract Drought stress severely limits the growth, development, and productivity of crops, and therefore understanding the mechanisms by which plants respond to drought is crucial. In this study, we cloned a maize NAC transcription factor, ZmNAC49, and identified its function in response to drought stress. We found that ZmNAC49 is localized in the nucleus and has transcriptional activation activity. ZmNAC49 expression is rapidly and strongly induced by drought stress, and overexpression enhances stress tolerance in maize. Overexpression also significant decreases the transpiration rate, stomatal conductance, and stomatal density in maize. Detailed study showed that ZmNAC49 overexpression affects the expression of genes related to stomatal development, namely ZmTMM, ZmSDD1, ZmMUTE, and ZmFAMA. In addition, we found that ZmNAC49 can directly bind to the promoter of ZmMUTE and suppress its expression. Taken together, our results show that the transcription factor ZmNAC49 represses ZmMUTE expression, reduces stomatal density, and thereby enhances drought tolerance in maize.

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

Horticultura Brasileira ◽

10.1590/s0102-053620170415 ◽

2017 ◽

Vol 35 (4) ◽

pp. 571-575 ◽

Cited By ~ 1

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.

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Genetic diversity of sunflower genotypes under drought stress by principle component analysis

Genetika ◽

10.2298/gensr2001029h ◽

2020 ◽

Vol 52 (1) ◽

pp. 29-41

Author(s):

Ejaz-Ul Hasan ◽

Ahmad Khan ◽

Sajida Habib ◽

Hafeez Sadaqat ◽

Shahzad Basra

Keyword(s):

Drought Stress ◽

Stomatal Conductance ◽

Transpiration Rate ◽

Root Weight ◽

Environmental Variance ◽

Drought Tolerant ◽

Drought Stress Condition ◽

Additive Gene ◽

High Heritability ◽

Shoot Weight

Seventy diverse genotypes were evaluated for drought stress for morphological (shoot and root length, fresh and dry shoot weight, fresh and dry root weight) and physiological traits (stomatal conductance, photosynthesis and transpiration rate) to increase the area under arid and semi-arid climatic condition to overcome the deficiency of edible oil. All genotypes varied significantly for all evaluated traits. High variability for photosynthesis rate and lower for transpiration rate but highly significant. Genotypic variance and its coefficient are almost higher for all characters then environmental variance and its coefficient. Additive gene action was found for stomatal conductance and fresh root weight, good characters for selection having high heritability with increased genetic advance used to find out drought tolerating genotypes. Genotypes ORI 29 and ORI 30 performed better in normal and drought stress condition can be used further breeding programme as a drought tolerant material. In PCA, genotypes ORI 30, ORI 27, ORI 38 and ORI 105 expressed maximum diversity can be used in further hybrid programme.

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

Pesquisa Agropecuária Tropical ◽

10.1590/1983-40632016v4747885 ◽

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.

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Gas exchange and putrescine content as drought stress indicators in corn cultivars fertilized with silicon

Australian Journal of Crop Science ◽

10.21475/ajcs.20.14.08.p2339 ◽

2020 ◽

pp. 1252-1258

Author(s):

Hudson Carvalho Bianchini ◽

Douglas Jose Marques

Keyword(s):

Drought Stress ◽

Stomatal Conductance ◽

Gas Exchange ◽

Grain Yield ◽

Transpiration Rate ◽

Morphological Changes ◽

Maize Yield ◽

Maize Cultivars ◽

Effects Of Drought ◽

Negative Impacts

The effects of drought stress on maize have been extensively reported in tropical and subtropical areas, including morphological changes in plants and reductions in the grain yield. The development of sustainable alternatives that help mitigate the negative impacts of water stress is indispensable for the development of agricultural crops. This study evaluates the effect of silicon fertilization in two irrigation blades, on gas exchange, putrescine content, quantification of Ca, K, Zn, and Fe by neutron activation and grain yield in two maize cultivars, tolerant and sensitive to drought stress. Two experiments were conducted, the first using BR-1010 (sensitive to drought stress) and the second using DKB-390 (tolerant to drought stress), in 19 dm-3 pots with one plant in each pot. The experiment was organized in randomized blocks, in a factorial scheme, combining two irrigation blades (30 percent and 100 percent of necessary water replacement) and two silicon conditions per pots: control (-Si), and 27g Si (+Si) using calcium silicate (10.5 percent Si) with four replicates. The contents of putrescine, Ca, K, Zn, and Fe, as well as transpiration rate, stomatal conductance, and net photosynthetic contents were quantified. Maize yield was measured at the end of the study. It was concluded that supplementation with Si contributes to a 12 percent increase in yield for BR-1010 (drought sensitive) and 14 percent for DKB-390 (drought tolerant). Si increased the net photosynthetic rate, transpiration rate, and stomatal conductance in DKB-390. The content of putrescine increased in plants submitted to drought stress and can be considered as an indicator of drought stress. The leaf contents of Ca, K, Zn, and Fe varied according to the cultivars and water blade studied.

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

Horticultura Brasileira ◽

10.1590/s0102-0536-20210110 ◽

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.

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Indole Acetic Acid (IAA) Mediated Amelioration of Lead (Pb) Stress- Physiological Indices of Mung Bean [Vigna radiata (L.) Wilczek]

Legume Research - An International Journal ◽

10.18805/lr-630 ◽

2021 ◽

Author(s):

Sana Saleem ◽

Ghulam Yasin ◽

Ikram Ul Haq ◽

Adeela Altaf ◽

Khalid Hussain ◽

...

Keyword(s):

Acetic Acid ◽

Stomatal Conductance ◽

Transpiration Rate ◽

Mung Bean ◽

Indole Acetic Acid ◽

Sandy Loam ◽

Co2 Concentration ◽

Pb Stress ◽

Loam Soil

Background: Heavy metals have their adverse effects on growth and physiology of plant. Plant growth regulators help in improving the growth and physiological phenomenon in plants. A pot culture experiment was devised to explore the ameliorative potential of Indole Acetic Acid (IAA) for toxicity of rhizospheric lead (Pb) on two varieties of Mung bean [Vigna radiate (L.) Wickzek]. Methods: Seeds of two varieties i.e., M- 8 and MN-92 were grown in earthen pots filled with sandy loam soil and were arranged under complete randomization. Fifteen days after germination, the lead (Pb) was added @ 10mg/kg and 20mg/kg soil as solution Pb NO3. Indole Acetic Acid @100.0mM was foliarly sprayed twice at 15 and 30 days of plants emergence. Physiological parameters i.e., Photosynthetic Rate, Transpiration Rate, Stomatal conductance, Sub Stomatal CO2 Concentration and biomass production in the form of stem, root and leaf dry weights were determined at the age of physiological maturity for three replicates. Result: By application of IAA, photostnthetic rate reduction was declined from 24.61% to 17.78% under 10mg Pb stress and from 55.54% to 27.35% under 20mg Pb stress. Stomatal conductance reduction was declined from 0.56% to 0.28% under 10mg Pb stress and from 3.37% to 1.68% under 20mg Pb stress. Alleviation of Pb stress by IAA for transpiration rate was non significant. Similarly, the role of IAA for alleviation of Pb stress in term of dry weights of stem,root and leaves were non significant statistically.

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