scholarly journals Gas exchange, Chlorophyll Fluorescence and Pigments of Noni (Morinda citrifolia L.) under Salt Stress

2018 ◽  
Vol 10 (2) ◽  
pp. 318
Author(s):  
A. M. W. Cova ◽  
André D. Azevedo Neto ◽  
Hans R. Gheyi ◽  
Rogério F. Ribas ◽  
Leandra B. De Oliveira ◽  
...  
Keyword(s):  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Gas Exchange ◽  
Chlorophyll A ◽  
Water Status ◽  
Stomatal Closure ◽  
Membrane Integrity ◽  
Climatic Conditions ◽  
Morinda Citrifolia ◽  
Total Carotenoids

Noni is a fruit crop well adapted to different soil and climatic conditions. Aiming to evaluate the physiological responses to salinity, noni seedlings were grown in two levels of NaCl (0 and 100 mM) in nutrient solution and the effects of salt stress on gas exchange, chlorophyll a fluorescence, photosynthetic pigments, relative water content and membrane integrity were assessed after 1, 10, 20, 30 and 40 days of salt stress. The experimental design was a completely randomized in 2 × 5 factorial arrangement with four replications. Salinity did not affect the intrinsic efficiency of water use, but reduced net assimilation of CO2, stomatal conductance, transpiration, carboxylation efficiency and contents of chlorophyll a, b, and total carotenoids. Salinity caused no major changes in chlorophyll fluorescence, however the stressed plants showed a decrease in photoprotection capacity by the cycle of xanthophylls. Salinity did not affect the water status of the leaves, but damages to the integrity of the membranes were observed due to duration of salt exposure. The data indicate that noni presents stomatal closure as a mechanism of salinity tolerance, reducing water loss by transpiration and maintaining the water status.

scholarly journals Characterizing Concentration Effects of Exogenous Abscisic Acid on Gas Exchange, Water Relations, and Growth of Muskmelon Seedlings during Water Stress and Rehydration

2012 ◽  
Vol 137 (6) ◽  
pp. 400-410 ◽  
Author(s):  
Shinsuke Agehara ◽  
Daniel I. Leskovar
Keyword(s):  
Abscisic Acid ◽  
Water Stress ◽  
Gas Exchange ◽  
Water Status ◽  
Stomatal Closure ◽  
Membrane Integrity ◽  
Dry Matter Accumulation ◽  
Assimilation Rate ◽  
Concentration Effects ◽  
Post Stress

Excess transpiration relative to water uptake often causes water stress in transplanted vegetable seedlings. Abscisic acid (ABA) can limit transpirational water loss by inducing stomatal closure and inhibiting leaf expansion. We examined the concentration effect of exogenous ABA on growth and physiology of muskmelon (Cucumis melo L.) seedlings during water stress and rehydration. Plants were treated with seven concentrations of ABA (0, 0.24, 0.47, 0.95, 1.89, 3.78, and 7.57 mm) and subjected to 4-day water withholding. Application of ABA improved the maintenance of leaf water potential and relative water content, while reducing electrolyte leakage. These effects were linear or exponential to ABA concentration and maximized at 7.57 mm. Gas-exchange measurements provided evidence that such stress control is attributed to ABA-induced stomatal closure. First, net CO2 assimilation rate and stomatal conductance initially decreased with increasing ABA concentration by up to 95% and 70%, respectively. A follow-up study (≤1.89 mm ABA) confirmed this result with or without water stress and further revealed a close positive correlation between intercellular CO2 concentration and net CO2 assimilation rate 1 day after treatment (r2 > 0.83). In contrast, ABA did not affect leaf elongation, indicating that stress alleviation was not mediated by leaf area adjustment. After 18 days of post-stress daily irrigation, dry matter accumulation showed a quadratic concentration-response, increasing up to 1.89 mm by 38% and 44% in shoot and roots, respectively, followed by 16% to 18% decreases at >1.89 mm ABA. These results suggest that excess levels of ABA delay post-stress growth, despite the positive effect on the maintenance of water status and membrane integrity. Another negative side effect was chlorosis, which accelerated linearly with increasing ABA concentration, although it was reversible upon re-watering. The optimal application rate of ABA should minimize these negative effects, while keeping plant water stress to an acceptable level.

scholarly journals Variations in leaf gas exchange, chlorophyll fluorescence and membrane potential of Medicago sativa root cortex cells exposed to increased salinity: The role of the antioxidant potential in salt tolerance

2018 ◽  
Vol 70 (3) ◽  
pp. 413-423 ◽  
Author(s):  
Mohamed Farissi ◽  
Mohammed Mouradi ◽  
Omar Farssi ◽  
Abdelaziz Bouizgaren ◽  
Cherki Ghoulam
Keyword(s):  
Antioxidant Enzymes ◽  
Salt Stress ◽  
Chlorophyll Fluorescence ◽  
Membrane Potential ◽  
Salt Tolerance ◽  
Gas Exchange ◽  
Medicago Sativa ◽  
Leaf Gas Exchange ◽  
Root Cortex ◽  
Root Cortex Cells

Salinity is one of the most serious agricultural problems that adversely affects growth and productivity of pasture crops such as alfalfa. In this study, the effects of salinity on some ecophysiological and biochemical criteria associated with salt tolerance were assessed in two Moroccan alfalfa (Medicago sativa L.) populations, Taf 1 and Tata. The experiment was conducted in a hydro-aeroponic system containing nutrient solutions, with the addition of NaCl at concentrations of 100 and 200 mM. The salt stress was applied for a month. Several traits in relation to salt tolerance, such as plant dry biomass, relative water content, leaf gas exchange, chlorophyll fluorescence, nutrient uptake, lipid peroxidation and antioxidant enzymes, were analyzed at the end of the experiment. The membrane potential was measured in root cortex cells of plants grown with or without NaCl treatment during a week. The results indicated that under salt stress, plant growth and all of the studied physiological and biochemical traits were significantly decreased, except for malondialdehyde and H2O2 contents, which were found to be increased under salt stress. Depolarization of membrane root cortex cells with the increase in external NaCl concentration was noted, irrespective of the growth conditions. The Tata population was more tolerant to high salinity (200 mM NaCl) and its tolerance was associated with the ability of plants to maintain adequate levels of the studied parameters and their ability to overcome oxidative stress by the induction of antioxidant enzymes, such as guaiacol peroxidase, catalase and superoxide dismutase.

Developing controlled environment screening for high-temperature tolerance in cotton that accurately reflects performance in the field

2012 ◽  
Vol 39 (8) ◽  
pp. 670 ◽  
Author(s):  
Nicola S. Cottee ◽  
Michael P. Bange ◽  
Iain W. Wilson ◽  
Daniel K. Y. Tan
Keyword(s):  
Chlorophyll Fluorescence ◽  
Gas Exchange ◽  
Cell Membrane ◽  
Heat Tolerance ◽  
Membrane Integrity ◽  
Screening Tools ◽  
Cultivar Differences ◽  
Physiological Performance ◽  
Cell Membrane Integrity ◽  
Multi Level

In this study we investigated the heat tolerance of high yielding Australian cotton (Gossypium hirsutum L.) cultivars using a multi-level approach encompassing physiological assays and measurements of performance. Two cultivars with known field performance were evaluated for heat tolerance under optimal (32°C) and high (42°C) temperatures in a growth cabinet with a cell membrane integrity assay. Impacts of temperature on growth were evaluated with leaf level measurements of gas exchange and chlorophyll fluorescence. To extend the multi-level approach, the expression of a Rubisco activase regulating gene (GhRCAα2) was also determined. Consistent with previously determined differences in the field, cultivar Sicot 53 outperformed Sicala 45 for the cell membrane integrity assay; this finding was reflective of cultivar differences in gas exchange and chlorophyll fluorescence. Cultivar differences were also consistent for expression of GhRCAα2, which may also help explain differences in physiological performance, particularly photosynthesis. This study reaffirmed that physiological and molecular assays were sufficiently sensitive to resolve genotypic differences in heat tolerance and that these differences translate to physiological performance. By comparing performance under high temperatures in the growth cabinet and field, this approach validates the use of rapid screening tools in conjunction with a multi-level approach for heat tolerance detection.

scholarly journals Growth, Physiological and Biochemical Responses of two Greek Cotton Cultivars to Salt Stress and their Impact as Selection Indices for Salt Tolerance

2019 ◽  
Vol 47 (3) ◽  
Author(s):  
Maria-Anna MOUSSOURAKI ◽  
Eleni TANI ◽  
Anna VELLIOU ◽  
Maria GOUFA ◽  
Maria PSYCHOGIOU ◽  
...  
Keyword(s):  
Salt Stress ◽  
Gas Exchange ◽  
Stress Responses ◽  
Ion Homeostasis ◽  
Membrane Integrity ◽  
Dry Weight ◽  
Agricultural Product ◽  
Digital Object Identifier ◽  
Sensitivity Index ◽  
Nacl Concentration

Soil salinity is a major constrain of crop productivity. Upland cotton (Gossypium hirsutum L.) is an important fiber crop worldwide and a major agricultural product in Greece. Two commercial cotton cultivars (‘Hersi’ and ‘ST 318’) were studied to compare their response under non-saline and saline conditions in a greenhouse experiment. Salt stress on plants was imposed by two different approaches: a gradual and an initial acclimatization to a non-lethal NaCl concentration (150 mM). To explore salt stress responses, growth (height of plants, roots, shoots and leaves dry weight, reproductive shoots, Salinity Sensitivity Index), gas exchange (Photosynthetic rate, Stomatal conductance, Transpiration rate and Water Use Efficiency) and biochemical parameters (proline, H2O2 and MDA content), were examined as well as ion homeostasis. ‘Hersi’ had significantly higher dry weight of roots, shoots and leaves, lower salinity sensitivity index of roots compared to ‘ST 318’.  In this regard, it appears that ‘Hersi’ cultivar performed better than ‘ST 318’ to increased salinity conditions, due to better control of gas exchange parameters and K+/Na+ homeostasis as well as better membrane integrity. Furthermore, the gradual acclimatization to the 150 mM NaCl concentration had a milder effect on both cultivars compared to the initial acclimatization.   ********* In press - Online First. Article has been peer reviewed, accepted for publication and published online without pagination. It will receive pagination when the issue will be ready for publishing as a complete number (Volume 47, Issue 3, 2019). The article is searchable and citable by Digital Object Identifier (DOI). DOI link will become active after the article will be included in the complete issue. *********

scholarly journals Grafting cv. Grechetto Gentile Vines to New M4 Rootstock Improves Leaf Gas Exchange and Water Status as Compared to Commercial 1103P Rootstock

Agronomy ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 708 ◽  
Author(s):  
Tommaso Frioni ◽  
Arianna Biagioni ◽  
Cecilia Squeri ◽  
Sergio Tombesi ◽  
Matteo Gatti ◽  
...  
Keyword(s):  
Water Stress ◽  
Gas Exchange ◽  
Water Use ◽  
Leaf Gas Exchange ◽  
Water Status ◽  
Stomatal Closure ◽  
Leaf Water ◽  
Summer Drought ◽  
Co2 Uptake ◽  
Drought Tolerant

M4 is a relatively new rootstock that was selected for increased resilience of vineyards across hot regions where meteorological drought is often coupled to water scarcity. However, M4 has thus far been tested only against water-stress sensitive rootstocks. Against this backdrop, the aim of the present work is to examine the water status and gas exchange performances of vines grafted to M4 in comparison to those of vines grafted to a commercial stock that is drought-tolerant, 1103 Paulsen (1103P), under a progressive water deficit followed by re-watering. This study was undertaken on Grechetto Gentile, a cultivar that is renowned for its rather conservative water use (near-isohydric behavior). While fifty percent of both grafts were fully irrigated (WW), the remaining underwent progressive water stress by means of suspending irrigation (WS). Soil and leaf water status, as well as leaf gas exchanges, along with chlorophyll fluorescence, were followed daily from 1 day pre-stress (DOY 176) until re-watering (DOY 184). Final leaf area per vine, divided in main and lateral contribution, was also assessed. While 1103P grafted vines manifested higher water use under WW conditions, progressive stress evidenced a faster water depletion by 1103P, which also maintained slightly more negative midday leaf water potential (Ψleaf) as compared to M4 grafted plants. Daily gas exchange readings, as well as diurnal assessment performed at the peak of stress (DOY 183), also showed increased leaf assimilation rates (A) and water use efficiency (WUE) in vines grafted on M4, which were also less susceptible to photosynthetic downregulation. Dynamic of stomatal closure targeted at 90% reduction of leaf stomatal conductance showed a similar behavior among rootstocks since the above threshold was reached by both at Ψleaf of about −1.11 MPa. The same fractional reduction in leaf A was reached by vines grafted on M4 at a Ψleaf of −1.28 MPa vs. −1.10 MPa measured in 1103P, meaning that using M4 as a rootstock will postpone full stomatal closure. While mechanisms involved in improved CO2 uptake in M4-grafted vines under moderate-to-severe stress are still unclear, our data support the hypothesis that M4 might outscore the performance of a commercial drought-tolerant genotype (1103P) and can be profitably used as a tool to improve the resilience of vines to summer drought.

scholarly journals Potassium doses on the ecophysiological characteristics of ‘Syrah’ grapevine grown at São Francisco River Valley, Brazil

2016 ◽  
Vol 7 (3) ◽  
pp. 362 ◽  
Author(s):  
Agnaldo Rodrigues de Melo Chaves ◽  
Davi José José Silva ◽  
Saulo Tarso Tarso Aidar ◽  
Luciana Martins Martins Santos ◽  
Karinne Albuquerque Albuquerque Campos de Prado ◽  
...  
Keyword(s):  
Gas Exchange ◽  
Chlorophyll A ◽  
Chlorophyll A Fluorescence ◽  
Potassium Nitrate ◽  
Climatic Conditions ◽  
Potassium Sulfate ◽  
Growth Stages ◽  
Physiological Variables ◽  
Grapevine Cultivar ◽  
Potassium Sources

The nutrients availability can lead to changes on grapevines physiological behavior, which results in a great importance of studies regarding the application of potassium doses. The aim of this research was to evaluate the ecophysiological behavior of grapevine cultivar ‘Syrah’ growing under different potassium doses by fertigation, according to the determination of gas exchange, chlorophyll a, fluorescence and pigments index. Five years old plants, grafted on ‘Paulsen 1103’ rootstock, in a trellis system and planted at theBebedouro Experimental Field, located in Petrolina, PE, Brazil, were evaluated. The experiment was composed by five potassium doses (0, 20, 40, 80 and 160 kg ha-1), applied by fertigation. The potassium sources were potassium sulfate, potassium nitrate and potassium chloride. The evaluations of the ecophysiologyical parameters were performed at four different times (07am, 10am, 1pm and 3pm) throughout the day on the flowering stage and the first and second fruit growth stages, determining gas exchange and chlorophyll a fluorescence and the pigments index was evaluated at the same grapevines leaves one time. Considering each evaluation period, it was observed that, according to the magnitude of the results for gas exchange, chlorophyll a fluorescence and pigments index, is not possible to indicate the best potassium dose. The climatic conditions during each period of evaluation influenced most the eco-physiological variables than the applied potassium doses, while the changes on pigments index were due to leaves development during the plant cycle.

scholarly journals Ascorbate–Glutathione Oxidant Scavengers, Metabolome Analysis and Adaptation Mechanisms of Ion Exclusion in Sorghum under Salt Stress

2021 ◽  
Vol 22 (24) ◽  
pp. 13249
Author(s):  
Himani Punia ◽  
Jayanti Tokas ◽  
Anurag Malik ◽  
Andrzej Bajguz ◽  
Mohamed A. El-Sheikh ◽  
...  
Keyword(s):  
Salt Stress ◽  
Antioxidant Activities ◽  
Water Status ◽  
Membrane Integrity ◽  
Metabolome Analysis ◽  
Higher Plant ◽  
Ion Transporter ◽  
Cell Membrane Integrity ◽  
Ion Exclusion ◽  
Sorghum Genotypes

Salt stress is one of the major significant restrictions that hamper plant development and agriculture ecosystems worldwide. Novel climate-adapted cultivars and stress tolerance-enhancing molecules are increasingly appreciated to mitigate the detrimental impacts of adverse stressful conditions. Sorghum is a valuable source of food and a potential model for exploring and understanding salt stress dynamics in cereals and for gaining a better understanding of their physiological pathways. Herein, we evaluate the antioxidant scavengers, photosynthetic regulation, and molecular mechanism of ion exclusion transporters in sorghum genotypes under saline conditions. A pot experiment was conducted in two sorghum genotypes viz. SSG 59-3 and PC-5 in a climate-controlled greenhouse under different salt concentrations (60, 80, 100, and 120 mM NaCl). Salinity drastically affected the photosynthetic machinery by reducing the accumulation of chlorophyll pigments and carotenoids. SSG 59-3 alleviated the adverse effects of salinity by suppressing oxidative stress (H2O2) and stimulating enzymatic and non-enzymatic antioxidant activities (SOD, APX, CAT, POD, GR, GST, DHAR, MDHAR, GSH, ASC, proline, GB), as well as protecting cell membrane integrity (MDA, electrolyte leakage). Salinity also influenced Na+ ion efflux and maintained a lower cytosolic Na+/K+ ratio via the concomitant upregulation of SbSOS1, SbSOS2, and SbNHX-2 and SbV-Ppase-II ion transporter genes in sorghum genotypes. Overall, these results suggest that Na+ ions were retained and detoxified, and less stress impact was observed in mature and younger leaves. Based on the above, we deciphered that SSG 59-3 performed better by retaining higher plant water status, photosynthetic assimilates and antioxidant potential, and the upregulation of ion transporter genes and may be utilized in the development of resistant sorghum lines in saline regions.

Delayed chlorophyll a fluorescence, MR 820, and gas exchange changes in perennial ryegrass under salt stress

2017 ◽  
Vol 183 ◽  
pp. 322-333 ◽  
Author(s):  
P. Dąbrowski ◽  
M.H. Kalaji ◽  
A.H. Baczewska ◽  
B. Pawluśkiewicz ◽  
G. Mastalerczuk ◽  
...  
Keyword(s):  
Salt Stress ◽  
Gas Exchange ◽  
Chlorophyll A ◽  
Perennial Ryegrass ◽  
Chlorophyll A Fluorescence
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