Physiological Responses of Amaranthus Cruentus L. to Drought Stress Under Sufficient- and Deficient-Nitrogen Conditions

2021 ◽  
Author(s):  
Inês Cechin ◽  
Laura Prado da Silva ◽  
Elisa Teófilo Ferreira ◽  
Sarah Corrêa Barrochelo ◽  
Fernanda Pereira de Souza Rosa de Melo ◽  
...  
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Photosynthetic Pigments ◽  
Dry Matter ◽  
Nitrogen Availability ◽  
Leaf Nitrogen ◽  
Nitrogen Supply ◽  
Plant Performance ◽  
In Planta ◽  
Phenolic Contents

Abstract Water and nitrogen availability are environmental factors that can impair plant growth, and when they are combined their effects can be intensified or reduced. The objective of this study was to analyse the influence of nitrogen availability on the responses of Amaranthus cruentus’s metabolisms to water stress. The plants were cultivated in plastic pots filled with vermiculite and kept under greenhouse conditions and were watered with 70% of full strength nitrogen-free Long Ashton solution, containing 1.97 or 9.88 kg N ha−1 as ammonium nitrate, three times a week. Photosynthetic parameter were evaluated in planta and leaves were harvested for chemical analysis of proline and phenolic contents. Higher nitrogen supply increased the shoot dry matter, photosynthetic pigments, photosynthesis, stomatal conductance, transpiration, total leaf nitrogen, proline, nitrate and ammonium but reduced the concentration of flavonoids and total phenols. Water stress for 6 days did not affect dry matter, photosynthetic pigments, leaf nitrogen, ammonium or specialized metabolites but increased the proline and affected negatively the other variables. The observed interactions between nitrogen and water supply resulted in no alleviation of the negative effects of drought on amaranth. Although the increase in nitrogen supply had benefits on plant performance, it intensified the negative effect of water stress. The study shows the importance of choosing the correct level of nitrogen fertilization in order to obtain satisfactory results in terms of plant growth under drought conditions.

scholarly journals Interactive Impacts of Beneficial Microbes and Si-Zn Nanocomposite on Growth and Productivity of Soybean Subjected to Water Deficit under Salt-Affected Soil Conditions

Plants ◽  
2021 ◽  
Vol 10 (7) ◽  
pp. 1396
Author(s):  
Hany S. Osman ◽  
Salah M. Gowayed ◽  
Mohssen Elbagory ◽  
Alaa El-Dein Omara ◽  
Ahmed M. Abd El-Monem ◽  
...  
Keyword(s):  
Water Stress ◽  
Stomatal Conductance ◽  
Plant Growth ◽  
Photosynthetic Pigments ◽  
Soil Salinity ◽  
Root Length ◽  
Seed Quality ◽  
Dry Weight ◽  
Soil Conditions ◽  
Salt Affected Soil

Water stress or soil salinity is considered the major environmental factor affecting plant growth. When both challenges are present, the soil becomes infertile, limiting plant productivity. In this work a field experiment was conducted during the summer 2019 and 2020 seasons to evaluate whether plant growth-promoting microbes (PGPMs) and nanoparticles (Si-ZnNPs) have the potential to maintain soybean growth, productivity, and seed quality under different watering intervals (every 11 (IW0), 15 (IW1) and 19 (IW2) days) in salt-affected soil. The most extended watering intervals (IW1 and IW2) caused significant increases in Na+ content, and oxidative damage indicators (malondialdehyde (MDA) and electrolyte leakage (EL%)), which led to significant reductions in soybean relative water content (RWC), stomatal conductance, leaf K+, photosynthetic pigments, soluble protein. Subsequently reduced the vegetative growth (root length, nodules dry weight, and total leaves area) and seeds yield. However, there was an enhancement in the antioxidants defense system (enzymatic and non-enzymatic antioxidant). The individual application of PGPMs or Si-ZnNPs significantly improved leaf K+ content, photosynthetic pigments, RWC, stomatal conductance, total soluble sugars (TSS), CAT, POD, SOD, number of pods plant−1, and seed yield through decreasing the leaf Na+ content, MDA, and EL%. The combined application of PGPMs and Si-ZnNPs minimized the adverse impact of water stress and soil salinity by maximizing the root length, heavier nodules dry weight, leaves area, TSS and the activity of antioxidant enzymes, which resulted in higher soybean growth and productivity, which suggests their use under harsh growing conditions.

Influence of Light Regime and Leaf Nitrogen Concentration on 77k Fluorescence in Leaves of Four Tropical Grasses: No Evidence for Photoinhibition

1988 ◽  
Vol 15 (5) ◽  
pp. 669 ◽  
Author(s):  
MM Ludlow ◽  
SP Samarakoon ◽  
JR Wilson
Keyword(s):  
Nitrogen Content ◽  
Nitrogen Availability ◽  
Nitrogen Concentration ◽  
Chlorophyll Concentration ◽  
Leaf Nitrogen ◽  
Nitrogen Supply ◽  
Poor Growth ◽  
Full Sunlight ◽  
Nitrogen Treatments ◽  
Low Nitrogen

This work was undertaken to determine if the stimulation of growth associated with shading of some tropical C4 grasses growing on soils with low to moderate nitrogen availability is partly due to overcoming photoinhibition (i. e. damage caused by excessive light). Four grasses (green panic, carpet grass, buffalo grass and kikuyu) were grown in full sunlight and at 37% of full sunlight, and given a low or high nitrogen supply. Despite differences of up to twofold in leaf nitrogen and chlorophyll concentration between high and low nitrogen treatments in all four grasses, photoinhibition measured by reduction in chlorophyll fluorescence was less than 3% in leaves of low nitrogen content that developed in full sunlight. Therefore, photoinhibition is not a contributor to the poor growth of nitrogen-limited grasses in full sunlight. A second objective was to determine if low nitrogen content predisposed shade-grown leaves to photoinhibition when they were subsequently exposed to full sunlight. Green panic plants that had been given either high or low nitrogen supply and grown in 37% of full sunlight were transferred to full sunlight and the extent of photoinhibition was followed over 8 days. The amount of photoinhibition that occurred was small (<6%) compared with plants grown at either nitrogen level in full sunlight. Therefore, shade and low nitrogen content separately or in combination did not cause any appreciable photoinhibition in green panic.

A long-term experiment to study the role of mulches in the physiology and macro-nutrition of strawberry grown under water stress

2001 ◽  
Vol 52 (9) ◽  
pp. 937 ◽  
Author(s):  
Halil Kirnak ◽  
Cengiz Kaya ◽  
David Higgs ◽  
Sinan Gercek
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Electrolyte Leakage ◽  
Dry Matter ◽  
Fruit Size ◽  
Bare Soil ◽  
Fruit Yield ◽  
Control Treatment ◽  
Wheat Straw Mulch ◽  
Polyethylene Mulch

Strawberry (Fragaria × ananassa Duch) cv. ‘Oso Grande’ was grown in the field from July 1999 to May 2000 in order to investigate the effectiveness of different mulch types on fruit yield, quality (i.e. soluble dry matter, fruit size), leaf nutrient compositions, and normal plant growth parameters in strawberry grown under water stress. Treatments were: (1) bare soil + water stressed (WS), (2) bare soil + unstressed (control), (3) black polyethylene mulch + water stressed (BPM + WS), (4) wheat straw mulch + water stressed (WSM + WS), (5) wheat straw mulch plus black polyethylene mulch + water stressed (WSM + BPM + WS). Water stress was created by irrigating plants once every 3 days at 50% A pan (Epan) evaporation, compared with the control, which received 75% daily. WS caused reductions in all parameters, except water-soluble dry matter concentrations in fruits, compared with the control treatment. Both BPM and WSM improved the fruit yield, fruit size, plant dry matter, leaf area index, and chlorophyll concentrations in leaves in the stressed treatments, while these 2 mulches in combination (BPM + WSM) caused further increases in these parameters. WS enhanced electrolyte leakage by impairing membrane permeability compared with control treatment. Mulching, especially BPM and WSM together, substantially decreased electrolyte leakage. WS reduced leaf concentrations of all nutrients tested (N, P, K, Ca, and Mg). However, mulching, especially BPM and WSM together, enhanced the concentrations of these nutrients, but their concentrations were still lower than those in the control treatment. These results clearly indicate that mulching mitigates negative effects of water stress on plant growth and fruit yield in field-grown strawberry, particularly in semi-arid situations.

scholarly journals Nonnodulating Bradyrhizobium spp. Modulate the Benefits of Legume-Rhizobium Mutualism

2016 ◽  
Vol 82 (17) ◽  
pp. 5259-5268 ◽  
Author(s):  
Kelsey A. Gano-Cohen ◽  
Peter J. Stokes ◽  
Mia A. Blanton ◽  
Camille E. Wendlandt ◽  
Amanda C. Hollowell ◽  
...  
Keyword(s):  
Plant Growth ◽  
Root Nodules ◽  
Experimental Treatment ◽  
Plant Performance ◽  
In Planta ◽  
Content Type ◽  
Fitness Effects ◽  
Native Legume ◽  
Bradyrhizobium Spp ◽  
Soil Interface

ABSTRACTRhizobia are best known for nodulating legume roots and fixing atmospheric nitrogen for the host in exchange for photosynthates. However, the majority of the diverse strains of rhizobia do not form nodules on legumes, often because they lack key loci that are needed to induce nodulation. Nonnodulating rhizobia are robust heterotrophs that can persist in bulk soil, thrive in the rhizosphere, or colonize roots as endophytes, but their role in the legume-rhizobium mutualism remains unclear. Here, we investigated the effects of nonnodulating strains on the nativeAcmispon-Bradyrhizobiummutualism. To examine the effects on both host performance and symbiont fitness, we performed clonal inoculations of diverse nonnodulatingBradyrhizobiumstrains onAcmispon strigosushosts and also coinoculated hosts with mixtures of sympatric nodulating and nonnodulating strains. In isolation, nonnodulatingBradyrhizobiumstrains did not affect plant performance. In most cases, coinoculation of nodulating and nonnodulating strains reduced host performance compared to that of hosts inoculated with only a symbiotic strain. However, coinoculation increased host performance only under one extreme experimental treatment. Nearly all estimates of nodulating strain fitness were reduced in the presence of nonnodulating strains. We discovered that nonnodulating strains were consistently capable of coinfecting legume nodules in the presence of nodulating strains but that the fitness effects of coinfection for hosts and symbionts were negligible. Our data suggest that nonnodulating strains most often attenuate theAcmispon-Bradyrhizobiummutualism and that this occurs via competitive interactions at the root-soil interface as opposed toin planta.IMPORTANCERhizobia are soil bacteria best known for their capacity to form root nodules on legume plants and enhance plant growth through nitrogen fixation. Yet, most rhizobia in soil do not have this capacity, and their effects on this symbiosis are poorly understood. We investigated the effects of diverse nonnodulating rhizobia on a native legume-rhizobium symbiosis. Nonnodulating strains did not affect plant growth in isolation. However, compared to inoculations with symbiotic rhizobia, coinoculations of symbiotic and nonnodulating strains often reduced plant and symbiont fitness. Coinoculation increased host performance only under one extreme treatment. Nonnodulating strains also invaded nodule interiors in the presence of nodulating strains, but this did not affect the fitness of either partner. Our data suggest that nonnodulating strains may be important competitors at the root-soil interface and that their capacity to attenuate this symbiosis should be considered in efforts to use rhizobia as biofertilizers.

Corrigendum to: A long-term experiment to study the role of mulches in the physiology and macro-nutrition of strawberry grown under water stress

2002 ◽  
Vol 53 (9) ◽  
pp. 1085
Author(s):  
Halil Kirnak ◽  
Cengiz Kaya ◽  
David Higgs ◽  
Sinan Gercek
Keyword(s):  
Water Stress ◽  
Plant Growth ◽  
Electrolyte Leakage ◽  
Dry Matter ◽  
Fruit Size ◽  
Bare Soil ◽  
Fruit Yield ◽  
Control Treatment ◽  
Wheat Straw Mulch ◽  
Polyethylene Mulch

Strawberry (Fragaria × ananassa Duch) cv. ‘Oso Grande’ was grown in the field from July 1999 to May 2000 in order to investigate the effectiveness of different mulch types on fruit yield, quality (i.e. soluble dry matter, fruit size), leaf nutrient compositions, and normal plant growth parameters in strawberry grown under water stress. Treatments were: (1) bare soil + water stressed (WS), (2) bare soil + unstressed (control), (3) black polyethylene mulch + water stressed (BPM + WS), (4) wheat straw mulch + water stressed (WSM + WS), (5) wheat straw mulch plus black polyethylene mulch + water stressed (WSM + BPM + WS). Water stress was created by irrigating plants once every 3 days at 50% A pan (Epan) evaporation, compared with the control, which received 75% daily. WS caused reductions in all parameters, except water-soluble dry matter concentrations in fruits, compared with the control treatment. Both BPM and WSM improved the fruit yield, fruit size, plant dry matter, leaf area index, and chlorophyll concentrations in leaves in the stressed treatments, while these 2 mulches in combination (BPM + WSM) caused further increases in these parameters. WS enhanced electrolyte leakage by impairing membrane permeability compared with control treatment. Mulching, especially BPM and WSM together, substantially decreased electrolyte leakage. WS reduced leaf concentrations of all nutrients tested (N, P, K, Ca, and Mg). However, mulching, especially BPM and WSM together, enhanced the concentrations of these nutrients, but their concentrations were still lower than those in the control treatment. These results clearly indicate that mulching mitigates negative effects of water stress on plant growth and fruit yield in field-grown strawberry, particularly in semi-arid situations.

Nitrogen fertilisation influences low CO2 effects on plant performance

2020 ◽  
Vol 47 (2) ◽  
pp. 134
Author(s):  
André G. Duarte ◽  
Fred J. Longstaffe ◽  
Danielle A. Way
Keyword(s):  
Nitrogen Availability ◽  
Leaf Nitrogen ◽  
Plant Performance ◽  
N Availability ◽  
Low Co2 ◽  
Co2 Effects ◽  
Co2 Concentrations ◽  
History Of ◽  
N Isotopes ◽  
Elymus Canadensis

Low atmospheric CO2 conditions prevailed for most of the recent evolutionary history of plants. Such concentrations reduce plant growth compared with modern levels, but low-CO2 effects on plant performance may also be affected by nitrogen availability, since low leaf nitrogen decreases photosynthesis, and CO2 concentrations influence nitrogen assimilation. To investigate the influence of N availability on plant performance at low CO2, we grew Elymus canadensis at ambient (~400 μmol mol–1) and subambient (~180 μmol mol–1) CO2 levels, under four N-treatments: nitrate only; ammonium only; a full and a half mix of nitrate and ammonium. Growth at low CO2 decreased biomass in the full and nitrate treatments, but not in ammonium and half plants. Low CO2 effects on photosynthetic and maximum electron transport rates were influenced by fertilisation, with photosynthesis being most strongly impacted by low CO2 in full plants. Low CO2 reduced stomatal index in half plants, suggesting that the use of this indicator in paleo-inferences can be influenced by N availability. Under low CO2 concentrations, nitrate plants discriminated more against 15N whereas half plants discriminated less against 15N compared with the full treatment, suggesting that N availability should be considered when using N isotopes as paleo-indicators.

scholarly journals Promotion of Growth and Physiological Characteristics in Water-Stressed Triticum aestivum in Relation to Foliar-Application of Salicylic Acid

Water ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1316
Author(s):  
Abida Parveen ◽  
Muhammad Arslan Ashraf ◽  
Iqbal Hussain ◽  
Shagufta Perveen ◽  
Rizwan Rasheed ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Salicylic Acid ◽  
Antioxidant Enzymes ◽  
Water Stress ◽  
Photosynthetic Pigments ◽  
Foliar Spray ◽  
Field Capacity ◽  
Available Water ◽  
Drought Tolerant ◽  
Growth Attributes

The present work reports the assessment of the effectiveness of a foliar-spray of salicylic acid (SA) on growth attributes, biochemical characteristics, antioxidant activities and osmolytes accumulation in wheat grown under control (100% field capacity) and water stressed (60% field capacity) conditions. The total available water (TAW), calculated for a rooting depth of 1.65 m was 8.45 inches and readily available water (RAW), considering a depletion factor of 0.55, was 4.65 inches. The water contents corresponding to 100 and 60% field capacity were 5.70 and 1.66 inches, respectively. For this purpose, seeds of two wheat cultivars (Fsd-2008 and S-24) were grown in pots subjected to water stress. Water stress at 60% field capacity markedly reduced the growth attributes, photosynthetic pigments, total soluble proteins (TSP) and total phenolic contents (TPC) compared with control. However, cv. Fsd-2008 was recorded as strongly drought-tolerant and performed better compared to cv. S-24, which was moderately drought tolerant. However, water stress enhanced the contents of malondialdehyde (MDA), hydrogen peroxide (H2O2) and membrane electrolyte leakage (EL) and modulated the activities of antioxidant enzymes (superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), as well as accumulation of ascorbic acid (AsA), proline (Pro) and glycine betaine (GB) contents. Foliar-spray with salicylic acid (SA; 0, 3 mM and 6 mM) effectively mitigated the adverse effects of water stress on both cultivars. SA application at 6 mM enhanced the shoot and root length, as well as their fresh and dry weights, and improved photosynthetic pigments. SA foliage application further enhanced the activities of antioxidant enzymes (SOD, POD, and CAT) and nonenzymatic antioxidants such as ascorbic acid and phenolics contents. However, foliar-spray of SA reduced MDA, H2O2 and membrane permeability in both cultivars under stress conditions. The results of the present study suggest that foliar-spray of salicylic acid was effective in increasing the tolerance of wheat plants under drought stress in terms of growth attributes, antioxidant defense mechanisms, accumulation of osmolytes, and by reducing membrane lipid peroxidation.

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