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

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>

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

Horticulturae ◽  
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.

scholarly journals Comparative research of photosynthetic processes in selected poikilohydric organisms from Mediterranean and Central-European alpine habitats

2018 ◽  
Vol 8 (2) ◽  
pp. 286-298
Author(s):  
Gabriella Nora Maria Giudici ◽  
Josef Hájek ◽  
Miloš Barták ◽  
Svatava Kubešová
Keyword(s):  
Czech Republic ◽  
Chlorophyll Fluorescence ◽  
Photochemical Quenching ◽  
Marchantia Polymorpha ◽  
Effective Quantum Yield ◽  
Response Curves ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Mediterranean Habitats ◽  
Non Photochemical Quenching

Dehydration-induced decrease in photosynthetic activity was investigated in five poikilohydric autotrophs using chlorophyll fluorescence parameters recorded during controlled desiccation. For the study, two representatives of mosses from alpine zone (Rhizomnium punctatum, Rhytidiadelphus squarrosus) of the Jeseníky Mts. (Czech Republic) were used. Other two experimental species were mediterranean habitats liverwort (Pellia endiviifolia) and moss (Palustriella commutata), collected from under Woodwardia radicans canopy in the Nature Reserve Valle delle Ferriere (Italy). The last species was a liverwort (Marchantia polymorpha) collected from lowland site (Brno, Moravia, Czech Republic). We investigated the relationship between relative water content (RWC) and several chlorophyll fluorescence parameters evaluating primary photochemical processes of photosynthesis, such as effective quantum yield of photosynthetic processes in photosystem II (ΦPSII), and non-photochemical quenching (qN). With desiccation from fully wet (RWC = 100%) to dry state (RWC = 0%), ΦPSII exhibited a rapid (R. punctatum) and slow decline of ΦPSII (R. squarrosus, P. endiviifolia, M. polymorpha, and P. commutata). Shapes of dehydration-response curves were species-specific. RWC0.5, i.e. the RWC at which the sample showed half of maximum ΦPSII, reflected the species-specificity. It reached 65% in desiccation sensitive (R. punctatum), 53% and 43% in semi-tolerant (P. commutata and R. squarrosus), 24% and 18% in desiccation-tolerant species (P. endiviifolia and M. polymorpha). In all experimental species, non-photochemical quenching (qN) of absorbed light energy showed high values at RWC = 100% and a slight increase with desiccation. Steady state chlorophyll fluorescence (FS) remained high during desiccation and was not correlated with ΦPSII.  

scholarly journals Phenylalanine Ammonia-Lyase and Source-Flow-Sink Related Attributes in Rice Genotypes Subjected to High Night Temperatures

2017 ◽  
Vol 9 (12) ◽  
pp. 268 ◽  
Author(s):  
Diogo S. Moura ◽  
Giovani G. Brito ◽  
Ângela D. Campos ◽  
Ítalo L. Moraes ◽  
Paulo R. R. Fagundes ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Phenylalanine Ammonia Lyase ◽  
Soluble Sugars ◽  
Grain Weight ◽  
Photochemical Quenching ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Temperature Regimes ◽  
Rice Genotypes ◽  
1000 Grain Weight

Phenylalanine ammonia-lyase (PAL) which is considered to be one of the main lines of cell acclimation against stress in plants, non-structural carbohydrates (NSC) accumulation and chlorophyll fluorescence parameters were quantified in two rice genotypes as a function of two temperature regimes: 22/30 °C (control) and 28/30 °C night/day (high night temperatures - HNT), imposed from heading to milk stage. The rice cultivars chosen were Nagina22 (N22) and BRS Querência (BRS-Quer), which are genotypes tolerant and sensitive to high temperatures, respectively. BRS-Quer genotype highlighted more sensitive responses maintaining higher PAL and peroxidase levels on seventh and twenty-first days after stress imposing. On the other hand, this genotype showed levels of fructose, glucose and sucrose decreasingly across stress period whether compared to N22. Both genotypes showed similarity for most of the chlorophyll fluorescence parameters. However, the photosynthesis induction curve highlighted that HNT caused decreases in some photochemical quenching of fluorescence as well as increases of non-phochemical quenching, affecting more prominently BRS-Quer genotype. N22 maintained unaltered the spikelet sterility and 1000-grain weight across temperature regimes showing a consistent trend with its stem NSC accumulation during stress period. The higher availability of soluble sugars shown by N22 at the end of stress period could be unloaded in spikelet formation and grain fillings contributing in their lower sterility rate and greater 1000-grain weight stability across the environments. These results indicate that selecting genotypes with higher capacity to stem NSC translocation beyond accumulation at HNT could lead to more grain yield stability in future climate scenarios.

scholarly journals Drought stress strengthens the link between chlorophyll fluorescence parameters and photosynthetic traits

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e10046 ◽  
Author(s):  
Jie Zhuang ◽  
Yonglin Wang ◽  
Yonggang Chi ◽  
Lei Zhou ◽  
Jijing Chen ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Drought Stress ◽  
Terrestrial Ecosystems ◽  
Stomatal Limitation ◽  
Chlorophyll Fluorescence Parameters ◽  
Fluorescence Parameters ◽  
Total Chlorophyll Content ◽  
Leaf Level ◽  
Photosynthetic Traits ◽  
Quantum Efficiency Of Psii

Chlorophyll fluorescence (ChlF) has been used to understand photosynthesis and its response to climate change, particularly with satellite-based data. However, it remains unclear how the ChlF ratio and photosynthesis are linked at the leaf level under drought stress. Here, we examined the link between ChlF ratio and photosynthesis at the leaf level by measuring photosynthetic traits, such as net CO2 assimilation rate (An), the maximum carboxylation rate of Rubisco (Vcmax), the maximum rate of electron transport (Jmax), stomatal conductance (gs) and total chlorophyll content (Chlt). The ChlF ratio of the leaf level such as maximum quantum efficiency of PSII (Fv/Fm) is based on fluorescence kinetics. ChlF intensity ratio (LD685/LD740) based on spectrum analysis was obtained. We found that a combination of the stomatal limitation, non-stomatal limitation, and Chlt regulated leaf photosynthesis under drought stress, while Jmax and Chlt governed the ChlF ratio. A significant link between the ChlF ratio and An was found under drought stress while no significant correlation in the control, which indicated that drought stress strengthens the link between the ChlF ratio and photosynthetic traits. These results suggest that the ChlF ratio can be a powerful tool to track photosynthetic traits of terrestrial ecosystems under drought stress.

The quantum yield of photosynthetic electron transport evaluated by chlorophyll fluorescence as an indicator of drought tolerance in durum wheat

1995 ◽  
Vol 125 (3) ◽  
pp. 325-329 ◽  
Author(s):  
Z. Flagella ◽  
D. Pastore ◽  
R. G. Campanile ◽  
N. Di Fonzo
Keyword(s):  
Chlorophyll Fluorescence ◽  
Electron Transport ◽  
Quantum Yield ◽  
Drought Tolerance ◽  
Durum Wheat ◽  
Photosynthetic Electron Transport ◽  
Fluorescence Measurement ◽  
Chlorophyll Fluorescence Parameters ◽  
Percentage Decrease ◽  
Induction Curve

SUMMARYThe chlorophyll fluorescence parameters ΔF/Fm′ and Fv′/Fm′, related respectively to the quantum yield of photosynthetic electron transport and to the efficiency of excitation capture by the open centres of photosystem II, have been evaluated as possible indicators of drought tolerance in durum wheat. ΔF/Fm′ and Fv′/Fm′ measurements were carried out on excised leaves, both control and dehydrated, of 25 cultivars. ΔF/Fm′ and Fv′/Fm′ values were obtained at two times after the start of fluorescence measurement: at 14 s, i.e. during the induction curve (ΔF/Fm′14s and Fv′/Fm′14s) and at 200s, i.e. at steady state fluorescence (ΔF/Fm′200s and Fv′/Fm′200s).In dehydrated leaves a mean significant decrease of 20% (P < 0·001) was observed in ΔF/Fm′14s values. In contrast, no great differences were observed between control and dehydrated leaves with regard to ΔF/Fm′200s, Fv′/Fm′14s and Fv′/Fm′200s.The percentage decrease of ΔF/Fm′14s after dehydration was correlated with the drought susceptibility index (DSI) of the cultivars, evaluated on a yield basis and a significant correlation (r = 0·72, P < 0·001) was found.

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

Agronomy ◽  
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.

Sign in / Sign up

Export Citation Format

Share Document