Monitoring of Salinity, Temperature, and Drought Stress in Grafted Watermelon Seedlings Using Chlorophyll Fluorescence

Chlorophyll fluorescence (CF) is used to measure the physiological status of plants affected by biotic and abiotic stresses. Therefore, we aimed to identify the changes in CF parameters in grafted watermelon seedlings exposed to salt, drought, and high and low temperatures. Grafted watermelon seedlings at the true three-leaf stage were subjected to salinity levels (0, 50, 100, 150, and 200 mM) and temperature [low (8°C), moderate (24°C), and high (40°C)] stresses for 12 days under controlled environmental conditions independently. Eight CF parameters were measured at 2-day intervals using the FluorCam machine quenching protocol of the FluorCam machine. The seedlings were also exposed to drought stress for 3 days independent of salinity and temperature stress; CF parameters were measured at 1-day intervals. In addition, growth parameters, proline, and chlorophyll content were evaluated in all three experiments. The CF parameters were differentially influenced depending on the type and extent of the stress conditions. The results showed a notable effect of salinity levels on CF parameters, predominantly in maximum quantum yield (Fv/Fm), non-photochemical quenching (NPQ), the ratio of the fluorescence decrease (Rfd), and quantum yield of non-regulated energy dissipation in PSII [Y(NO)]. High temperature had significant effects on Rfd and NPQ, whereas low temperature showed significant results in most CF parameters: Fv/Fm, Y(NO), NPQ, Rfd, the efficiency of excitation capture of open photosystem II (PSII) center (Fv′/Fm′), and effective quantum yield of photochemical energy conversion in PSII [Y(PSII)]. Only NPQ and Rfd were significantly influenced by severe drought stress. Approximately, all the growth parameters were significantly influenced by the stress level. Proline content increased with an increase in stress levels in all three experiments, whereas the chlorophyll (a and b) content either decreased or increased depending upon the stressor. The results provided here may be useful for understanding the effect of abiotic stresses on CF parameters and the selection of index CF parameters to detect abiotic stresses in grafted watermelon seedlings.

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Effect of Drought Stress on Chlorophyll Fluorescence Parameters, Phytochemical Contents, and Antioxidant Activities in Lettuce Seedlings

Horticulturae ◽

10.3390/horticulturae7080238 ◽

2021 ◽

Vol 7 (8) ◽

pp. 238

Author(s):

Yu Kyeong Shin ◽

Shiva Ram Bhandari ◽

Jung Su Jo ◽

Jae Woo Song ◽

Jun Gu Lee

Keyword(s):

Ascorbic Acid ◽

Chlorophyll Fluorescence ◽

Drought Stress ◽

Quantum Yield ◽

Antioxidant Activities ◽

Growth Parameters ◽

Photochemical Quenching ◽

Total Phenol Content ◽

Effective Quantum Yield ◽

Chlorophyll Fluorescence Parameters

This study monitored changes in chlorophyll fluorescence (CF), growth parameters, soil moisture content, phytochemical content (proline, ascorbic acid, chlorophyll, total phenol content (TPC), and total flavonoid content (TFC)), and antioxidant activities in 12-day-old lettuce (Lactuca sativa L.) seedlings grown under drought stress (no irrigation) and control (well irrigated) treatments in controlled conditions for eight days. Measurements occurred at two-day intervals. Among ten CF parameters studied, effective quantum yield of photochemical energy conversion in PSII (Y(PSII)), coefficient of photochemical quenching (qP), and coefficient of photochemical quenching of variable fluorescence based on the lake model of PSII (qL) significantly decreased in drought-stressed seedlings from day 6 of treatment compared to control. In contrast, maximum quantum yield (Fv/Fm), ratio of fluorescence (Rfd), and quantum yield of non-regulated energy dissipation in PSII (Y(NO)) were significantly affected only at the end. All growth parameters decreased in drought-stressed seedlings compared to control. Proline started increasing from day 4 and showed ~660-fold elevation on day 8 compared to control. Chlorophyll, ascorbic acid, TPC, TFC, and antioxidant activities decreased in drought-stressed seedlings. Results showed major changes in all parameters in seedlings under prolonged drought stress. These findings clarify effects of drought stress in lettuce seedlings during progressive drought exposure and will be useful in the seedling industry.

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Response to Salt Stress in Lettuce: Changes in Chlorophyll Fluorescence Parameters, Phytochemical Contents, and Antioxidant Activities

Agronomy ◽

10.3390/agronomy10111627 ◽

2020 ◽

Vol 10 (11) ◽

pp. 1627

Author(s):

Yu Kyeong Shin ◽

Shiva Ram Bhandari ◽

Jung Su Jo ◽

Jae Woo Song ◽

Myeong Cheoul Cho ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Quantum Yield ◽

Antioxidant Activities ◽

Growth Parameters ◽

Photochemical Quenching ◽

Treatment Schedule ◽

Effective Quantum Yield ◽

Chlorophyll Fluorescence Parameters ◽

Nacl Concentration ◽

Phytochemical Contents

Chlorophyll fluorescence (CF), growth parameters, phytochemical contents [proline, chlorophyll, ascorbic acid, total phenol content (TPC), total flavonoid content (TFC)], and antioxidant activities were investigated in lettuce (Lactuca sativa L.) seedlings grown under different sodium chloride (NaCl) concentrations (0, 50, 100, 200, 300, and 400 mM) in a controlled environment for eight days. The parameters were evaluated at two days intervals. Almost of the CF and growth parameters as well as phytochemicals were significantly affected by both NaCl concentrations and progressive treatment schedule. The maximum quantum yield (Fv/Fm), effective quantum yield of photochemical energy conversion in PSII [Y(PSII)], coefficient of photochemical quenching (qP), coefficient of non-photochemical quenching (qN), and ratio of fluorescence decline (Rfd) showed decrements only at the highest saline concentration (400 mM), whereas the quantum yield of non-regulated energy dissipation in PSII [Y(NO)] exhibited a dissipation trend. All the growth parameters decreased with increasing NaCl concentrations, showing the highest decrease (~8 fold) in shoot fresh weight, compared to control seedlings. Proline significantly increased with increasing NaCl concentration and treatment time. Other phytochemicals decreased with the increase in NaCl concentration and reached their lowest at 400 mM. Overall, the results showed major changes in all parameters when the seedlings were grown at a NaCl concentration of 400 mM. The present findings will be useful for understanding the differential effect of NaCl concentrations in lettuce seedlings, and also might be useful to optimize the NaCl concentrations in other crops grown in controlled environmental conditions.

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Comparisons of Chlorophyll Fluorescence and Physiological Characteristics of Wheat Seedlings Influenced by Iso-Osmotic Stresses from Polyethylene Glycol and Sodium Chloride

Agronomy ◽

10.3390/agronomy10030325 ◽

2020 ◽

Vol 10 (3) ◽

pp. 325

Author(s):

Chiu-Yueh Lan ◽

Kuan-Hung Lin ◽

Chun-Liang Chen ◽

Wen-Dar Huang ◽

Chang-Chang Chen

Keyword(s):

Chlorophyll Fluorescence ◽

Polyethylene Glycol ◽

Sodium Chloride ◽

Energy Dissipation ◽

Quantum Yield ◽

Photochemical Quenching ◽

Effective Quantum Yield ◽

Wheat Seedlings ◽

Level 3 ◽

Level 2

Wheat (Triticum aestivum) cultivar Taichung SEL.2 (TCS2) is a salt-tolerance variety, but the mechanism involved remains unclear. This study aims to distinguish between the non-ionic osmotic and salt-mediated physiological effects on TCS2. Osmotic agents polyethylene glycol (PEG) and sodium chloride (NaCl) were applied at three iso-osmotic levels, level 1 containing 24% (w/v) PEG and 200 mM NaCl, level 2 containing 26.5% (w/v) PEG and 250 mM NaCl), and level 3 containing 29% (w/v) PEG and 300 mM NaCl, respectively. According to the investigation of chlorophyll fluorescence in the better NaCl-treated seedlings, maximal quantum yield of photosystem II (PSII) (Fv/Fm) and significant higher effective quantum yield of PSII (ΦPSII) at level 3 were observed. Meanwhile, the non-photochemical quenching of PSII (NPQ) and the quantum yield of regulated energy dissipation of PSII [Y(NPQ)] were significantly higher in the NaCl-treated seedlings, and the quantum yield of non-regulated energy dissipation of PSII [Y(NO)] in the NaCl-treated seedlings was lower than the PEG-treated ones at level 2 and level 3. Furthermore, the less extensive degradation of photosynthetic pigments, the better ascorbate peroxidase (APX) activity and the less accumulation of malondialdehyde (MDA) were also observed in NaCl-treated seedlings. In the morphological traits, shoot elongation in NaCl-treated seedlings was also preserved. These results suggest that TCS2 is more resistant to NaCl-induced osmotic stress than to the PEG-induced stress. This study contributes to plant breeder interest in drought- and/or salt-tolerant wheat varieties.

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Chlorophyll fluorescence response of wheat to exogenous application of growth regulators under terminal drought stress

Annales Universitatis Mariae Curie-Sklodowska sectio C – Biologia ◽

10.17951/c.2015.70.1.13 ◽

2015 ◽

Vol 70 (1) ◽

pp. 13

Author(s):

Hamid Mohammadi ◽

Mohsen Janmohammadi ◽

Naser Sabaghnia

Keyword(s):

Chlorophyll Fluorescence ◽

Drought Stress ◽

Electron Transport ◽

Quantum Yield ◽

Photochemical Quenching ◽

Chlorophyll Fluorescence Parameters ◽

Fluorescence Parameters ◽

Exogenous Application ◽

Terminal Drought ◽

Terminal Drought Stress

<p>Drought stress negatively affects plant photosynthesis and disturbs the electron transport activity. Evaluation of the chlorophyll fluorescence parameters might reflect influence of the environmental stress on plants and can be applied as an indicator of the primary photochemistry of photosynthesis. In current study the effect of foliar application of benzylaminopurine (BAP, a synthetic cytokinin) and abscisic acid (ABA) on chlorophyll fluorescence parameters of relatively drought tolerant (Pishtaz) and susceptible (Karaj3) bread wheat genotypes under well watered and terminal water deficit condition have been evaluated. Terminal drought was induced by withholding water at anthesis stage (Zadoks scale 65). Results showed that coefficient of non-photochemical quenching of variable fluorescence (qN), quantum yield of PS II photochemistry (ΦPSII) and photochemical quenching (qP) were affected by hormone spray treatments. So that evaluation of parameters at 7 day after foliar treatments revealed that ABA significantly increased electron transport rate (ETR) and qN while considerably decreased ΦPSII, gs and maximum quantum yield of photosystem II (Fv/Fm). However exogenous application of cytokinin could increase gs, Fv/Fm and ΦPSII and the highest value of these parameters was recorded in <em>cytokinin </em>treated plants of Pishtaze cv. under well watered condition. Nevertheless, evaluation of the parameters in different periods after spraying showed that with approaching the maturity stage some traits like as gs, Fv/Fm and ETR significantly decreased in both genotypes. Evaluation of gs and Chlorophyll fluorescence parameters of genotypes between different irrigation levels showed that although cv. Pishtaz showed higher performance of PSII under well watered condition, it failed to maintain its superiority under stress condition. This finding suggests that some more responsive parameter like gs, Fv/Fm and ΦPSII can be considered as reliable indicator for understanding the biochemical and physiological effects of exogenous application of phytohormones under terminal drought stress.</p>

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Effect of Up-Converting Luminescent Nanoparticles with Increased Quantum Yield Incorporated into the Fluoropolymer Matrix on Solanum lycopersicum Growth

Agronomy ◽

10.3390/agronomy12010108 ◽

2022 ◽

Vol 12 (1) ◽

pp. 108

Author(s):

Denis V. Yanykin ◽

Dmitriy E. Burmistrov ◽

Alexander V. Simakin ◽

Julia A. Ermakova ◽

Sergey V. Gudkov

Keyword(s):

Chlorophyll Fluorescence ◽

Quantum Yield ◽

Solanum Lycopersicum ◽

Red Light ◽

Photochemical Reactions ◽

Stem Length ◽

Photochemical Quenching ◽

Effective Quantum Yield ◽

Ir Radiation ◽

Luminescent Nanoparticles

The influence of light conversion induced by glasses coated with up-converting luminescent nanoparticles on Solanum lycopersicum cultivation was studied. Nanoparticles of Sr0.46Ba0.50Yb0.02Er0.02F2.04 solid solution were used as the up-converting luminophore. These nanoparticles were able to transform IR radiation into visible light (λem = 660 nm with minor peaks at 545 nm and 525 nm). By applying the “variable” chlorophyll fluorescence (ΔF), it was shown that the cultivation of tomatoes under the photoconversion glasses stimulated changes in the rate of plant adaptation to ultraviolet radiation. The restoration time of values of effective quantum yield of photosystem II photochemical reactions and photochemical quenching of chlorophyll fluorescence (reflecting disappearance of imbalance between photosynthetic electron transport and the utilization of NADPH) was reduced from three weeks to three days in the case of control and photoconversion films, respectively. As a result, plants grown under photoconversion glass had an increased leaf number (12.5%), total leaf area (33%), stem length (35%) and chlorophyll content in the leaves (two-fold). It is assumed that an increase in the proportion of red light in the growing spectrum has a positive effect on photosynthetic activity and plant growth.

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Effects of Alternating Fresh and Saline Water Irrigation on Soil Salinity and Chlorophyll Fluorescence of Summer Maize

Water ◽

10.3390/w12113054 ◽

2020 ◽

Vol 12 (11) ◽

pp. 3054

Author(s):

Honghui Sang ◽

Weihua Guo ◽

Yun Gao ◽

Xiyun Jiao ◽

Xiaobao Pan

Keyword(s):

Chlorophyll Fluorescence ◽

Quantum Yield ◽

Fresh Water ◽

Soil Salinity ◽

Saline Water ◽

Photochemical Quenching ◽

Effective Quantum Yield ◽

Summer Maize ◽

Saline Water Irrigation ◽

Heading Stage

Saline groundwater irrigation is an important way to alleviate the shortage of fresh water resources. In order to find a reasonable saline irrigation method for farmland, an irrigation experiment was conducted with fresh water and saline water at the seedling, jointing, heading, and filling stages. The soil salinity, growth, chlorophyll fluorescence, and yield of summer maize were measured. The results showed that alternating fresh and saline water irrigation led to a smaller increase in soil salinity relative to that irrigation with saline water alone. In addition, different sequences of alternating irrigation also significantly affected the accumulation of soil salinity. The maximum quantum yield, effective quantum yield of photochemical energy conversion, photochemical quenching, and non-photochemical quenching varied greatly at the jointing stage and heading stage. Furthermore, the yield of maize that was irrigated with fresh water at the heading stage (8.53 t ha−1) was greater than that at the jointing (7.69 t ha−1) and filling stages (7.45 t ha−1). Therefore, these findings indicate that in areas where fresh water is scarce, priority should be given to the application of fresh water at the heading stages for summer maize irrigation.

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Leaf Rolling Reduces Photosynthetic Loss in Maize Under Severe Drought

Acta Botanica Croatica ◽

10.2478/botcro-2014-0012 ◽

2014 ◽

Vol 73 (2) ◽

pp. 315-332 ◽

Cited By ~ 18

Author(s):

Aykut Saglam ◽

Asim Kadioglu ◽

Mehmet Demiralay ◽

Rabiye Terzi

Keyword(s):

Drought Stress ◽

Quantum Yield ◽

Photosystem Ii ◽

Grain Filling ◽

Severe Drought ◽

Effective Quantum Yield ◽

Leaf Rolling ◽

Kernel Weights ◽

Drought Tolerant ◽

Grain Filling Stage

Abstract Effects of leaf rolling (LR) on maize photosynthesis under severe drought stress were studied in two cultivars with opposite drought responses, Batem 56-55 (drought tolerant) and Batem 51-52 (drought sensitive). Drought stress and artificial prevention of leaf rolling (PLR) were applied at grain filling stage for 30 days. LR in Batem 56-55 occurred later than in Batem 51-52. Leaf water potential (Ψleaf) did not change in Batem 56-55 but decreased in Batem 51-52 at LR. Maximum quantum yield of photosystem II (Fv/Fm), effective quantum yield of photosystem II (ΦPSII) and electron transport rate (ETR) of the cultivars decreased during LR more significantly in Batem 56-55 in comparison to Batem 51-52. The same was observed for the decrease in net photosynthetic rate (Pn), stomatal conductance (gs), transpiration (E) and intracellular level of CO2 (C). Rubis-co activity and content were reduced at LR, but were less affected in Batem 56-55 than in Batem 51-52. Ear and kernel weights also decreased at LR. All parameters at PLR were more reduced than those of LR. These results implied that LR was an important and necessary mechanism protecting photosynthesis and reducing yield loss under drought stress by maintaining the leaf hydration, preventing loss of the photosynthetic pigments, sustaining the activity of PSU, keeping the stornata open, and conserving the activity of Rubisco.

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Spermine: Its Emerging Role in Regulating Drought Stress Responses in Plants

Cells ◽

10.3390/cells10020261 ◽

2021 ◽

Vol 10 (2) ◽

pp. 261

Author(s):

Md. Mahadi Hasan ◽

Milan Skalicky ◽

Mohammad Shah Jahan ◽

Md. Nazmul Hossain ◽

Zunaira Anwar ◽

...

Keyword(s):

Drought Stress ◽

Drought Tolerance ◽

Stress Responses ◽

Abiotic Stresses ◽

Defense Mechanisms ◽

Antioxidant Defense ◽

Severe Drought ◽

New Information ◽

Effects Of Drought

In recent years, research on spermine (Spm) has turned up a lot of new information about this essential polyamine, especially as it is able to counteract damage from abiotic stresses. Spm has been shown to protect plants from a variety of environmental insults, but whether it can prevent the adverse effects of drought has not yet been reported. Drought stress increases endogenous Spm in plants and exogenous application of Spm improves the plants’ ability to tolerate drought stress. Spm’s role in enhancing antioxidant defense mechanisms, glyoxalase systems, methylglyoxal (MG) detoxification, and creating tolerance for drought-induced oxidative stress is well documented in plants. However, the influences of enzyme activity and osmoregulation on Spm biosynthesis and metabolism are variable. Spm interacts with other molecules like nitric oxide (NO) and phytohormones such as abscisic acid, salicylic acid, brassinosteroids, and ethylene, to coordinate the reactions necessary for developing drought tolerance. This review focuses on the role of Spm in plants under severe drought stress. We have proposed models to explain how Spm interacts with existing defense mechanisms in plants to improve drought tolerance.

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Protective Effects of Selenium on Wheat Seedlings under Salt Stress

Agronomy ◽

10.3390/agronomy9060272 ◽

2019 ◽

Vol 9 (6) ◽

pp. 272 ◽

Cited By ~ 1

Author(s):

Chiu-Yueh Lan ◽

Kuan-Hung Lin ◽

Wen-Dar Huang ◽

Chang-Chang Chen

Keyword(s):

Salt Stress ◽

Chlorophyll Fluorescence ◽

Energy Dissipation ◽

Quantum Yield ◽

Photosystem Ii ◽

Physiological Traits ◽

Effective Quantum Yield ◽

Enzymatic Antioxidants ◽

Wheat Seedlings ◽

Chlorophyll Fluorescence Parameters

Wheat is a staple food worldwide, but its productivity is reduced by salt stress. In this study, the mitigative effects of 22 μM selenium (Se) on seedlings of the wheat (Triticum aestivum L.) cultivar Taichung SEL. 2 were investigated under different salt stress levels (0, 100, 200, 300, and 400 mM NaCl). Results of the antioxidative capacity showed that catalase (CAT) activity, non-enzymatic antioxidants (total phenols, total flavonoids, and anthocyanins), 1,1-Diphenyl-2-Picryl-Hydrazyl (DPPH) radical-scavenging activity, and the reducing power of Se-treated seedlings were enhanced under saline conditions. The more-stabilized chlorophyll fluorescence parameters (maximal quantum yield of photosystem II (Fv/Fm), minimal chlorophyll fluorescence (F0), effective quantum yield of photosystem II (ΦPSII), quantum yield of regulated energy dissipation of photosystem II (Y(NPQ)), and quantum yield of non-regulated energy dissipation of photosystem II (Y(NO)) and the less-extensive degradation of photosynthetic pigments (total chlorophyll and carotenoids) in Se-treated seedlings were also observed under salt stress. The elongation of shoots and roots of Se-treated seedling was also preserved under salt stress. Protection of these physiological traits in Se-treated seedlings might have contributed to stable growth observed under salt stress. The present study showed the protective effect of Se on the growth and physiological traits of wheat seedlings under salt stress.

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Effects of Drought and Rehydration on the Physiological Responses of Artemisia halodendron

Water ◽

10.3390/w11040793 ◽

2019 ◽

Vol 11 (4) ◽

pp. 793

Author(s):

Juanli Chen ◽

Xueyong Zhao ◽

Yaqiu Zhang ◽

Yuqiang Li ◽

Yongqing Luo ◽

...

Keyword(s):

Chlorophyll Fluorescence ◽

Drought Stress ◽

Membrane Permeability ◽

Chlorophyll Content ◽

Physiological Responses ◽

Severe Drought ◽

Native Plant ◽

Chlorophyll Fluorescence Parameters ◽

Artemisia Halodendron ◽

Effects Of Drought

Artemisia halodendron is a widely distributed native plant in China’s Horqin sandy land, but few studies have examined its physiological responses to drought and rehydration. To provide more information, we investigated the effects of drought and rehydration on the chlorophyll fluorescence parameters and physiological responses of A. halodendron to reveal the mechanisms responsible for A. halodendron’s tolerance of drought stress and the resulting ability to tolerate drought. We found that A. halodendron had strong drought resistance. Its chlorophyll content first increased and then decreased with prolonged drought. Variable chlorophyll fluorescence (Fv) and quantum efficiency of photosystem II (Fv/Fm) decreased, and the membrane permeability and malondialdehyde increased. When plants were subjected to drought stress, superoxide dismutase (SOD) activity degraded under severe drought, but the activities of peroxidase (POD) and catalase (CAT) and the contents of soluble proteins, soluble sugars, and free proline increased. Severe drought caused wilting of A. halodendron leaves and the leaves failed to recover even after rehydration. After rehydration, the chlorophyll content, membrane permeability, SOD and CAT activities, and the contents of the three osmoregulatory substances under moderate drought began to recover. However, Fv, Fv/Fm, malondialdehyde, and POD activity did not recover under severe drought. These results illustrated that drought tolerance of A. halodendron resulted from increased enzyme (POD and CAT) activities and accumulation of osmoregulatory substances.

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