Photoprotection in water-stressed plants of durum wheat (Triticum turgidum var. durum): changes in chlorophyll fluorescence, spectral signature and photosynthetic pigments

2002 ◽  
Vol 29 (1) ◽  
pp. 35 ◽  
Author(s):  
Eduardo A. Tambussi ◽  
Jaume Casadesus ◽  
Sergi Munné-Bosch ◽  
José Luis Araus
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Stress ◽  
Durum Wheat ◽  
Triticum Turgidum ◽  
Plant Stress ◽  
Co2 Assimilation ◽  
Photochemical Quenching ◽  
Spectral Signature ◽  
Antioxidant Defences ◽  
Carotene Content

We analysed the photoprotective response in water-stressed plants of durum wheat (Triticum turgidum L. var. durum cv. Mexa). The plants were grown in a greenhouse for 4 weeks and then exposed to water stress by withholding water for 8 d. Development of water stress was monitored as the decrease in relative water content (RWC) and net CO2 assimilation of the last fully developed leaf. The photoprotective response was evaluated in the same leaves by analysing modulated chlorophyll fluorescence, leaf spectroradiometrical changes, and pigment content. Measurements were performed 3, 6 (moderate stress) and 8 (severe stress) d after water-stress treatment began. The non-photochemical quenching of chlorophyll fluorescence (qN), as well as the contents of zeaxanthin and antheraxanthin increased significantly after 6 d of treatment. However, a further rise in these xanthophylls on day 8 was not associated with any increase in qN. In addition, the β-carotene content rose significantly on day 8, suggesting an increase in antioxidant defences. The photochemical index (PI), derived from spectroradiometrical measurements, showed a strong progressive drop on days 6 and 8, which was paralleled by an increase in the de-epoxidation state of the xanthophyll cycle (DPS), in particular by the zeaxanthin content. At midday, PI was strongly (negatively) correlated with DPS and qN. These results suggest that the PI may be a reliable indicator of photoprotection in the study of plant stress, and in breeding programs.

scholarly journals Changes in Photo-Protective Energy Dissipation of Photosystem II in Response to Beneficial Bacteria Consortium in Durum Wheat under Drought and Salinity Stresses

2020 ◽  
Vol 10 (15) ◽  
pp. 5031 ◽  
Author(s):  
Mohammad Yaghoubi Khanghahi ◽  
Sabrina Strafella ◽  
Carmine Crecchio
Keyword(s):  
Chlorophyll Fluorescence ◽  
Energy Dissipation ◽  
Quantum Yield ◽  
Photosystem Ii ◽  
Excitation Energy ◽  
Durum Wheat ◽  
Photochemical Quenching ◽  
Plant Growth Promoting Bacteria ◽  
Psii Photochemistry ◽  
Non Photochemical Quenching

The present research aimed at evaluating the harmless dissipation of excess excitation energy by durum wheat (Triticum durum Desf.) leaves in response to the application of a bacterial consortium consisting of four plant growth-promoting bacteria (PGPB). Three pot experiments were carried out under non-stress, drought (at 40% field capacity), and salinity (150 mM NaCl) conditions. The results showed that drought and salinity affected photo-protective energy dissipation of photosystem II (PSII) increasing the rate of non-photochemical chlorophyll fluorescence quenching (NPQ (non-photochemical quenching) and qCN (complete non-photochemical quenching)), as well as decreasing the total quenching of chlorophyll fluorescence (qTQ), total quenching of variable chlorophyll fluorescence (qTV) and the ratio of the quantum yield of actual PSII photochemistry, in light-adapted state to the quantum yield of the constitutive non-regulatory NPQ (PQ rate). Our results also indicated that the PGPB inoculants can mitigate the adverse impacts of stresses on leaves, especially the saline one, in comparison with the non-fertilized (control) treatment, by increasing the fraction of light absorbed by the PSII antenna, PQ ratio, qTQ, and qTV. In the light of findings, our beneficial bacterial strains showed the potential in reducing reliance on traditional chemical fertilizers, in particular in saline soil, by improving the grain yield and regulating the amount of excitation energy.

scholarly journals (454) Detecting Plant Stress by Chlorophyll Fluorescence

HortScience ◽  
2005 ◽  
Vol 40 (4) ◽  
pp. 1036C-1036
Author(s):  
Hussein Al-Amier ◽  
Robert Lussier ◽  
Ming Coler ◽  
Margaret Stoltzman ◽  
Lyle Craker
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Stress ◽  
Plant Tissue ◽  
Dark Adaptation ◽  
Photosynthetic Efficiency ◽  
Plant Stress ◽  
Fluorescence Emission ◽  
Sudden Increase ◽  
Stress Symptoms ◽  
Kautsky Effect

The stress level in a plant may be directly associated with the intensity of the Kautsky effect (the sudden increase in fluorescence emission by chlorophyll following a dark adaptation). The decrease in photosynthetic efficiency, linked with the rate of photochemistry of plants under stress, provides a definitive signature (graphical pattern) that can be quantified and monitored, even for plants that have no visible stress symptoms. Using a prototype GrowScanner®, signature differences in plants under nitrogen and water stress, as compared with plants not under stress, could be detected and measured. Returning stressed plants to a nonstressed condition returned the stress signatures to that of control plants not under stress. Development of the technology may provide a relatively quick, presymptomatic methodology for detecting plant stress without sacrificing plant tissue.

scholarly journals Identification of Lycopene epsilon cyclase (LCYE) gene mutants to potentially increase β-carotene content in durum wheat (Triticum turgidum L.ssp. durum) through TILLING

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0208948 ◽  
Author(s):  
Daniela Richaud ◽  
Claudia Stange ◽  
Agata Gadaleta ◽  
Pasqualina Colasuonno ◽  
Roberto Parada ◽  
...  
Keyword(s):  
Durum Wheat ◽  
Triticum Turgidum ◽  
Carotene Content ◽  
Β Carotene

Photosynthetic responses to chromosome doubling in relation to leaf anatomy in Lonicera japonica subjected to water stress

2009 ◽  
Vol 36 (9) ◽  
pp. 783 ◽  
Author(s):  
Wei-Dong Li ◽  
Dilip K. Biswas ◽  
Hong Xu ◽  
Chang-Qing Xu ◽  
Xian-Zhong Wang ◽  
...  
Keyword(s):  
Chlorophyll Fluorescence ◽  
Water Stress ◽  
Gas Exchange ◽  
Chromosome Doubling ◽  
Starch Content ◽  
Soluble Sugars ◽  
Net Photosynthesis ◽  
Lonicera Japonica ◽  
Photochemical Quenching ◽  
Effective Quantum Yield

Gas exchange, chlorophyll fluorescence, and contents of some metabolites in two Japanese honeysuckle (Lonicera japonica Thunb.) cultivars, Damaohua (2n = 2x) and Jiufengyihao (2n = 4x), were compared with explore the function of chromosome doubling under water stress conditions. Water stress significantly decreased net photosynthesis rate, stomatal conductance, and transpiration rate of both cultivars. It also decreased electron transport rate, effective quantum yield of Photosystem II, photochemical quenching, and starch content, but increased non-photochemical quenching and contents of total soluble sugars, proline, and malondialdehyde. However, the tetraploid cultivar showed higher resistance to water stress than the diploid, as indicated by the fact that gas exchange, chlorophyll fluorescence, and metabolites were less affected for the tetraploid than the diploid. Moreover, the tetraploid recovered more quickly than the diploid after re-watering. Morphological and anatomical analysis further revealed that the tetraploid possessed less whole plant leaf area, higher leaf mass per unit area, thicker epidermis (both upper and lower) and palisade tissue, as well as denser pubescence. All of those specialised structures caused by chromosome doubling might lead to greater capacity in coping with drought stress. Our findings suggest that the effect of chromosome doubling on drought resistance in L. japonica could attribute to the improvement of structure and photosynthesis-related traits.

Effects of water stress on photosynthesis, chlorophyll fluorescence and photoinhibition in wheat plants

1998 ◽  
Vol 25 (8) ◽  
pp. 883 ◽  
Author(s):  
Congming Lu ◽  
Jianhua Zhang
Keyword(s):  
Water Stress ◽  
Co2 Assimilation ◽  
Photochemical Quenching ◽  
Reaction Centre ◽  
Ps Ii ◽  
Energy Capture ◽  
Stress Effects ◽  
Reaction Centres ◽  
Net Co2 Assimilation ◽  
Non Photochemical Quenching

Effects of water stress on photosynthesis, PS II photochemistry and photoinhibition were investigated in wheat plants (Tritium aestivum L.). To separate water stress effects from photoinhibition, water stress was imposed at low irradiance (180 µmol m-2 s-1). When water stress developed gradually, net CO2 assimilation rate and leaf stomatal conductance decreased significantly. However, water stress had no effects on the PS II photochemistry in dark-adapted leaves. There were no significant changes in the maximal efficiency of PS II photochemistry and no apparent damages in PS II reaction centre, its oxidising and acceptor sides, or its antennae system. However, PS II photochemistry in light-adapted leaves was modified in water-stressed plants. This was shown by the decrease in the efficiency of excitation energy capture by open PS II reaction centres and the quantum yield of PS II electron transport and a significant increase in non-photochemical quenching. In addition, water stress increased the susceptibility to photoinhibition. The extent of photoinhibition became more pronounced as water stress increased. It was found that water-stressed plants exhibited a much greater accumulation of the QB-non-reducing PS II reaction centres and a smaller increase in non- photochemical quenching during photoinhibition. Such changes might be responsible for the increased susceptibility to photoinhibition.

RESPONSE OF DURUM WHEAT CULTIVARS TO WATER STRESS IN THE FIELD AND GREENHOUSE

1983 ◽  
Vol 63 (4) ◽  
pp. 801-814 ◽  
Author(s):  
GETINET GEBEYEHOU ◽  
D. R. KNOTT
Keyword(s):  
Water Stress ◽  
Durum Wheat ◽  
Drought Resistance ◽  
Yield Components ◽  
Triticum Turgidum ◽  
Kernel Weight ◽  
Greenhouse Experiment ◽  
Water Regimes ◽  
Growing Period ◽  
The Difference

Experiments were conducted in the field and in the greenhouse to measure differences in drought resistance among durum wheat (Triticum turgidum L.) cultivars. Nine cultivars were tested in 1976 and 12 in 1977 in duplicate tests grown adjacent to each other under rainfed and irrigated conditions in the field. The drought resistance of the cultivars was measured as the difference in their performance under the two water regimes. For yield, there was no significant interaction between the cultivars and the water regimes in either year. Thus, the cultivars did not appear to differ significantly in drought resistance. They did differ significantly in the effect of water stress on the yield components. However, the performance of the cultivars was not consistent either for the yield components or between years. In one greenhouse experiment, six cultivars were grown in large containers. One set of plants was watered at regular intervals while a second set was watered only until 5 days after anthesis in the main spikes. Water stress caused major, correlated reductions in grain yield, 1000-kernel weight, and length of the growing period. However, the differences among the cultivars largely depended on their vegetative growth under nonstress, those with the most growth showing the largest reduction from stress. In a second greenhouse experiment, the 12 cultivars were grown in 15-cm pots at three moisture levels. For yield, there was no interaction between cultivars and moisture levels. Overall, the data provided little evidence of consistent differences among cultivars in resistance to moisture stress.Key words: Drought resistance, components of yield, yield, durum wheat (Triticum turgidum L.).

scholarly journals Linking remote sensing parameters to CO2 assimilation rates at a leaf scale

2021 ◽  
Author(s):  
Kouki Hikosaka ◽  
Katsuto Tsujimoto
Keyword(s):  
Remote Sensing ◽  
Chlorophyll Fluorescence ◽  
Heat Dissipation ◽  
Spatial Scales ◽  
Photochemical Efficiency ◽  
Co2 Assimilation ◽  
Photochemical Quenching ◽  
Future Prediction ◽  
Environmental Responses ◽  
Non Photochemical Quenching

AbstractSolar-induced chlorophyll fluorescence (SIF) and photochemical reflectance index (PRI) are expected to be useful for remote sensing of photosynthetic activity at various spatial scales. This review discusses how chlorophyll fluorescence and PRI are related to the CO2 assimilation rate at a leaf scale. Light energy absorbed by photosystem II chlorophylls is allocated to photochemistry, fluorescence, and heat dissipation evaluated as non-photochemical quenching (NPQ). PRI is correlated with NPQ because it reflects the composition of xanthophylls, which are involved in heat dissipation. Assuming that NPQ is uniquely related to the photochemical efficiency (quantum yield of photochemistry), photochemical efficiencies can be assessed from either chlorophyll fluorescence or PRI. However, this assumption may not be held under some conditions such as low temperatures and photoinhibitory environments. Even in such cases, photosynthesis may be estimated more accurately if both chlorophyll fluorescence and PRI are determined simultaneously. To convert from photochemical efficiency to CO2 assimilation, environmental responses in stomatal conductance also need to be considered. Models linking chlorophyll fluorescence and PRI with CO2 assimilation rates will contribute to understanding and future prediction of the global carbon cycle.

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