0000000000276296
AUTHOR
Manuel Talon
Response of Spinach Leaves (Spinacia oleracea L.) to Ozone Measured by Gas Exchange, Chlorophyll a Fluorescence, Antioxidant Systems, and Lipid Peroxidation
Spinach (Spinacia oleracea L. cv. Clermont) leaves grown in open-top chambers and exposed to three different concentrations of ozone were measured for gas exchange, chlorophyll a fluorescence, antioxidant systems, and lipid peroxidation at the end of growing season. High O-3 concentration reduced F-v/F-m, indicating that the efficiency in the energy conversion of photosystem 2 (PS2) was altered. The rate of non-cyclic electron transport rate and the capacity to reduce the quinone pool were also affected. The development of non-photochemical quenching was not high enough to decrease the photon excess in the PS2. The limitation of photosynthetic activity was probably correlated with stomata c…
Responses of citrus plants to ozone: leaf biochemistry, antioxidant mechanisms and lipid peroxidation.
The effects of ozone upon 3-year-old trees of Clementina mandarin (Citrus clementina Hort. ex Tan.) cv. Marisol exposed for 12 months to ambient (10 nl l(-1)) and high (30 and 65 nl l(-1)) concentrations in open top chambers (OTCs) were investigated. The data showed that in leaves, ozone reduced total chlorophylls, carotenoid and carbohydrate concentration. and increased 1-aminocyclopropane-1-carboxylic acid (ACC) content and ethylene production. In treated plants, the ascorbate leaf pool was decreased, while lipid peroxidation and Solute leakaGe were significantly higher than in ozone-free controls. The data indicated that ozone triggered protective mechanisms against oxidative stress in c…
Effects of 2-month ozone exposure in spinach leaves on photosynthesis, antioxidant systems and lipid peroxidation
The photosynthesis response, antioxidant systems and lipid peroxidation were studied in leaves from spinach plants (Spinacia oleracea L.) in response to ozone fumigation, ambient air and charcoal filtered air treatments. The photosynthetic activity was tested through gas exchange and chlorophyll a fluorescence measurements. Ambient air and ozone fumigation caused a decrease in the photosynthetic rate (25% and 63%, respectively) mainly due to a reduced mesophyll activity, as evidenced by the increased intercellular CO, concentration. These data agree with a large reduction in the non-cyclic electron flow (7% and 16%), a lower capacity to reduce the quinone pool and a higher development of no…
Effects of long-term ozone exposure on citrus: Chlorophyll a fluorescence and gas exchange
Three-years-old trees of Satsuma mandarin (Citrus unshiu [Mak.] Marc.) cv. Okitsu were exposed to O-3 fumigation during long term (one year) in open-top chambers. As a result of the treatment, chlorophyll a fluorescence and gas exchange parameters were modified with respect to trees growing in O-3-free conditions. Net photosynthetic rate and stomatal conductance decreased and intercellular CO2 concentration increased according to a reduction of the non-cyclic electron flow and a lower capacity to reduce the quinone pool. O-3 also reduced the development of non-photochemical quenching preventing the dissipation of excess excitation energy and, therefore, generated several alterations in phot…
Cytological and molecular characterization of three gametoclones of Citrus clementina
Abstract Background Three gametoclonal plants of Citrus clementina Hort. ex Tan., cv. Nules, designated ESP, FRA, and ITA (derived from three labs in Spain, France, and Italy, respectively), were selected for cytological and molecular characterization in order to elucidate genomic rearrangements provoked by haploidization. The study included comparisons of their ploidy, homozygosity, genome integrity, and gene dosage, using chromosome counting, flow cytometry, SSR marker genotyping, and array-Comparative Genomic Hybridization (array-CGH). Results Chromosome counting and flow cytometry revealed that ESP and FRA were haploid, but ITA was tri-haploid. Homozygous patterns, represented by a sing…