Abstract Isoprene is formed in and emitted by plants the reason for this apparent carbon waste still unclear. It has been proposed that isoprene stabilizes cell particularly chloroplast thylakoid membranes. We tested if membrane stabilization or reactivity with ozone induces protection against acute exposures. The reduction of visible, physiological, anatomical, ultrastructural (chloroplast) damage shows clones sensitive to unable emit become resistant short exposure they are fumigated...

Abstract We investigated how the presence of cadmium (Cd) at emergence Phragmites australis Trin. (Cav.) ex Steudel plants from rhizomes interacted with leaf and chloroplast physiological biochemical processes. About 8.5 nmol Cd mg–1 chlorophyll was found in leaves, 0.83 chloroplasts treated 50 μm Cd. As a result, 30% loss measured concomitantly comparable percentage reduction light-saturated photosynthesis. Rubisco content activity were lowered by 10% 60%, respectively. Antioxidant...

Abstract The higher plant mitochondrial electron transport chain contains, in addition to the cytochrome chain, an alternative pathway that terminates with a single homodimeric protein, oxidase (AOX). We recorded temporary inhibition of capacity respiration and activation AOX tobacco plants (Nicotiana tabacum L. cv BelW3) fumigated ozone (O3). AOX1a gene was used as molecular probe investigate its regulation by signal molecules such hydrogen peroxide, nitric oxide (NO), ethylene (ET),...

Cadmium is an important environmental pollutant with high toxicity to plants. We report the effects of high‐dose Cd (100 µ M for 21 days) on root apparatus Phragmites australis plants, which are characterized by elevated water detoxification capacity and widely used in phytoremediation programmes. The examination sections light electron microscopy failed reveal any significant cadmium‐induced structural or ultra‐structural modifications. However, histochemical localization disclosed...

Abstract Treatment of the ozone-sensitive tobacco (Nicotiana tabacum L. cv Bel W3) with an ozone pulse (150 nL L–1 for 5 h) induced visible injury, which manifested 48 to 72 h from onset fumigation. The “classical” symptoms in W3 plants occur as sharply defined, dot-like lesions on adaxial side leaf and result death groups palisade cells. We investigated whether this reaction had features a hypersensitive response like that results incompatible plant-pathogen interaction. detected oxidative...

• Isoprene reduces visible damage (necrosis) of leaves caused by exposure to ozone but the mechanism is not known. Here we show that in Phragmites isoprene emission was stimulated after a 3-h high levels. The photosynthetic apparatus which inhibited fosmidomycin became more susceptible than isoprene-emitting leaves. Three days fumigation, necrotic leaf area significantly higher isoprene-inhibited Isoprene-inhibited also accumulated amounts nitric oxide (NO), as detected epifluorescence light...

Here, we analyse the temporal signatures of ozone (O3)-induced hydrogen peroxide(H2O2) and nitric oxide (NO) role second messenger guanosine3′,5′-cyclic monophosphate (cGMP) in transcriptional changes genes diagnostic for biotic abiotic stress responses. Within 90 min O3 induced H2O2 NO peaks demonstrate that donors cause rapid accumulation tobacco (Nicotiana tabacum) leaf. Ozone also causes highly significant, late (> 2 h) sustained cGMP increases, suggesting may not be required all early...

Bois noir is an important disease of grapevine (Vitis vinifera L.), caused by phytoplasmas. An interesting, yet elusive aspect the bois "recovery", i.e., spontaneous and unpredictable remission symptoms damage. Because conventional pest management ineffective against noir, deciphering molecular bases recovery beneficial. The present study aimed to understand whether salicylate- jasmonate-defence pathways might have a role in from grapevine. Leaves healthy, noir-diseased noir-recovered plants...

The direct and indirect impact of ozone on Populus alba was studied by exposing leaves enclosed in specially designed cuvettes for 30 days to high (150 ppb, 11 h per day), while developing above the were exposed ambient ozone. Gas exchanges histo‐anatomical parameters measured specifically understand whether indirectly affects anatomy physiology leaves. Three leaf classes investigated: (1) those expanding (A leaves); (2) already developed inside (B leaves) (3) cuvettes, since beginning...

ABSTRACT To analyse cellular response to O 3 , the tolerant Arabidopsis thaliana genotype Col‐0 was exposed fumigation (300 ppb) for 6 h and modulation of gene expression during treatment (3 after beginning treatment, T3 h) recovery phase (6 from end T12 assessed by chip microarray real‐time reverse transcriptase (RT)‐PCR analyses. The transcriptional profile is complex, as new genes (i.e. reticuline oxidase) pathways, other than those already reported ‐responsive, appear be involved in...

Air pollution is frequently proposed as a cause of the increased incidence allergy in industrialised countries. We investigated impact ozone (O(3)) on reactive oxygen species (ROS) and allergen content ragweed pollen (Ambrosia artemisiifolia). Pollen was exposed to acute O(3) fumigation, with analysis viability, ROS nitric oxide (NO) content, activity nicotinamide adenine dinucleotide phosphate (NAD[P]H) oxidase, expression major allergens. There decreased viability after which indicates...

Cyclic mononucleotides are messengers in plant stress responses. Here we show that hydrogen peroxide (H 2 O ) induces rapid net K + ‐efflux and Ca 2+ ‐influx Arabidopsis roots. Pre‐treatment with either 10 μM cAMP or cGMP for 1 24 h does significantly reduce ‐leakage ‐influx, the case of ‐fluxes, cell permeant cyclic more effective. We also examined effect 8‐Br‐cGMP on microsomal proteome noted a specific increase proteins role responses ion transport, suggesting is sufficient to directly...

We recently reported the transcriptomic signature of salicylic acid (SA) and jasmonic (JA) biosynthetic responsive genes in Arabidopsis thaliana plants infested with herbivore Eurydema oleracea. demonstrated that insect feeding causes induction both SA- JA-mediated signaling pathways. Using transgenic SA-deficient NahG plants, we also showed antagonistic cross-talk between these two phytohormones. To gain more insight into roles SA JA pathways plant defenses against E. oleracea, report here...

ABSTRACT The role that the constituents of ascorbate–glutathione cycle play in mechanism contrasting ozone sensitivities was examined mature and old tobacco leaves after acute ozone‐fumigation (150 p.p.b., 5 h). Levels enzyme activities associated with detoxifying system were lower ozone‐sensitive Bel W3 control plants than unfumigated ozone‐tolerant B plants. In particular, endogenous ascorbate peroxidase (APX) glutathione reductase (GR), metabolites ascorbic acid (AA) reduced (GSH) more...

ABSTRACT The alternative oxidase (AOX) of plant mitochondria transfers electrons from the ubiquinione pool to oxygen without energy conservation and prevents formation reactive species (ROS) when ubiquinone is over‐reduced. Thus, AOX may be involved in acclimation a number oxidative stresses. To test this hypothesis, we exposed wild‐type (WT) Xanthi tobacco plants as well transformed with Bright Yellow AOX1a cDNA enhanced (SN21 SN29), decreased (SN10) capacity an acute ozone (O 3 )...

The second messenger, 3', 5'-cyclic monophosphate (cGMP), is a critical component of many different processes in plants while guanylyl cyclases that catalyse the formation cGMP from GTP have remained somewhat elusive higher plants. Consequently, two major aims are discovery novel GCs and identification mediated processes. Recently, we reported temporal signatures ozone (O3)-induced hydrogen peroxide (H2O2) nitric oxide (NO) generation, their effect on consequent transcriptional changes genes...