Relationship between quantum efficiency of PSII and cold-induced plant resistance to fungal pathogens

2004 ◽  
Vol 26 (2) ◽  
pp. 141-148 ◽  
Author(s):  
Agnieszka Pła ek ◽  
Marcin Rapacz ◽  
Katarzyna Hura
Keyword(s):  
Quantum Efficiency ◽  
Plant Resistance ◽  
Fungal Pathogens ◽  
Induced Plant Resistance ◽  
Quantum Efficiency Of Psii

An increase in water deficit has no impact on the photosynthetic capacity of field-grown Mediterranean plants

2002 ◽  
Vol 29 (5) ◽  
pp. 621 ◽  
Author(s):  
Salvador Nogués ◽  
Leonor Alegre
Keyword(s):  
Water Deficit ◽  
Quantum Efficiency ◽  
Photosynthetic Capacity ◽  
Photosynthetic Parameters ◽  
Water Regimes ◽  
Relative Quantum ◽  
Mediterranean Plants ◽  
Psii Photochemistry ◽  
The Impact ◽  
Quantum Efficiency Of Psii

In the Mediterranean, annual mean precipitation has continuously decreased over the last three years (by ca 36% in Barcelona), and the decrease has been dramatic during the summer (by ca 78 and 64% during July and August, respectively). The impact of increased drought on the photosynthetic capacity of Mediterranean vegetation is currently unknown. In this study, two native Mediterranean plants [rosemary (Rosmarinus officinalis L.) and lavender (Lavandula stoechas L.)] were grown outdoors and subjected to two water regimes (50 mm month–1 during the summer, or no supplementary water at all). Rosemary and lavender plants watered with 50 mm month–1 during the summer had higher relative leaf water content and water potential than non-watered plants. Changes in water status were accompanied by large decreases in parameters of gas exchange [i.e. the light-saturated rate of CO2 assimilation, the maximum velocity of ribulose-1,5-bisphosphate (RuBP) carboxylation by Rubisco and the capacity for RuBP] and of modulated chlorophyll fluorescence (i.e. the relative quantum efficiency of PSII photochemistry and the efficiency of energy capture by open PSII reaction centres) during the summer, but no differences were found in any photosynthetic parameters for leaves subjected to the two water regimes. The drought-induced decreases in the relative quantum efficiency of PSII photochemistry in rosemary and lavender plants were attributable to ‘downregulation’ of electron transport. Photodamage to PSII in the field appeared to be a later effect of drought in these plants. Photorespiration was not a major mechanism protecting the photosynthetic apparatus of these plants from photodamage in the field. After the autumn rainfall, photosynthetic capacity fully recovered. We conclude that rosemary and lavender are well adapted to drought, and that an increase in water deficit is unlikely to have a significant impact on the photosynthetic capacity of leaves.

scholarly journals Chitinases—Potential Candidates for Enhanced Plant Resistance towards Fungal Pathogens

Agriculture ◽  
2018 ◽  
Vol 8 (7) ◽  
pp. 88 ◽  
Author(s):  
Manish Kumar ◽  
Amandeep Brar ◽  
Monika Yadav ◽  
Aakash Chawade ◽  
V. Vivekanand ◽  
...  
Keyword(s):  
Plant Resistance ◽  
Fungal Pathogens

scholarly journals Neighborhood Effects of Herbivore-Induced Plant Resistance Vary Along an Elevational Gradient

2020 ◽  
Vol 8 ◽  
Author(s):  
Rafael Fonseca Benevenuto ◽  
Tarald Seldal ◽  
Stein R. Moe ◽  
Cesar Rodriguez-Saona ◽  
Stein Joar Hegland
Keyword(s):  
Plant Resistance ◽  
Neighborhood Effects ◽  
Elevational Gradient ◽  
Induced Plant Resistance

Assessment of photoprotection mechanisms of grapevines at low temperature

2003 ◽  
Vol 30 (6) ◽  
pp. 631 ◽  
Author(s):  
Luke Hendrickson ◽  
Marilyn C. Ball ◽  
C. Barry Osmond ◽  
Robert T. Furbank ◽  
Wah Soon Chow
Keyword(s):  
Electron Transport ◽  
Low Temperature ◽  
Quantum Efficiency ◽  
Electron Flow ◽  
Strong Dependence ◽  
Photochemical Quenching ◽  
Vitis Vinifera L ◽  
Mehler Reaction ◽  
Sustained Reduction ◽  
Quantum Efficiency Of Psii

The photosynthetic response of grapevine leaves (Vitis vinifera L. cv. Riesling) to low temperature was studied in the field and laboratory. Light-saturated rates of photosynthetic electron transport were lower and non-photochemical energy dissipation was higher when leaves were subject to low morning temperatures than to high afternoon temperatures under field conditions. These responses to low temperatures occurred without sustained reduction of quantum efficiency of PSII as measured by the variable to maximum chlorophyll fluorescence yield ratio, Fv/Fm, after dark adaptation. The temperature dependence of light-saturated apparent electron transport rate, gas exchange and non-photochemical quenching (NPQ) was also examined in laboratory experiments with glasshouse-grown material. NPQ reached saturation at lower light intensity with decreasing temperature. The relationship between the quantum efficiency of PSII and CO2 fixation at 25°C (2–21% O2) and 10°C (2–21% O2) indicated a decreased dependence of electron transport on both photorespiration and the Mehler reaction at the lower temperature. The calculated percentage of electron flow to the Mehler reaction declined faster than photorespiration at low temperature. Warm- and cold-treated leaf discs under saturating light showed very little photoinhibition as measured by sustained reduction in Fv/Fm, which was linearly related to the percentage of functional PSII reaction centres. However, the addition of dithiothreitol greatly enhanced the rate of photoinhibition, indicating a potentially strong dependence on xanthophyll de-epoxidation for photoprotection at low temperature.

Cell biology of early events in the plant resistance response to infection by pathogenic fungi

1995 ◽  
Vol 73 (S1) ◽  
pp. 418-425 ◽  
Author(s):  
I. Kobayashi ◽  
L. J. Murdoch ◽  
A. R. Hardham ◽  
H. Kunoh
Keyword(s):  
Plant Resistance ◽  
Cell Biology ◽  
Fungal Pathogens ◽  
Plant Defence ◽  
Pathogenic Fungi ◽  
Callose Deposition ◽  
Resistance Response ◽  
New Genes ◽  
Host Cell Wall ◽  
Plant Cytoskeleton

In addition to passive (or constitutive) defence mechanisms, plants have evolved a range of active (or inducible) responses that occur rapidly on infection with an incompatible (avirulent) pathogen and that are thought to play a major role in the expression of resistance. These defence reactions are only induced if the plant possesses the ability to recognize and respond to the pathogen. Signal reception by the host must initiate a cascade of events that lead to the expression of resistance. Some resistance responses, such as callose deposition, do not require the expression of new genes. Many responses, for example the synthesis and secretion of toxic compounds or molecules that enhance the strength of physical barriers, result from changes in the pattern of gene transcription. Other defence phenomena include hypersensitive cell collapse, intercellular signalling, and the induction of defence gene transcripts in surrounding cells. Changes in cell biochemistry and physiology are accompanied by characteristic structural modifications in the infected cells, such as the redeployment of selected organelles and dramatic modifications of the host cell wall. Recent evidence indicates that microtubules and microfilaments of the plant cytoskeleton facilitate the rapid localization of these and other plant defence responses to the region of infection. Key words: plant resistance, plant cytoskeleton, microtubules, microfilaments, fungal pathogens, polarity of defence response.

scholarly journals Induced plant resistance

2012 ◽  
Vol 49 (3) ◽  
pp. 326-334 ◽  
Author(s):  
Gasic Katarina ◽  
Obradovic Aleksa
Keyword(s):  
Plant Resistance ◽  
Induced Plant Resistance
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