Search

Your search keyword '"Fq'/Fm'"' showing total 2 results
Start Over Descriptor "Fq'/Fm'"
2 results on '"Fq'/Fm'"'

1. Spectral Composition of Light Affects Sensitivity to UV-B and Photoinhibition in Cucumber

Author

Carl-Otto Ottosen, Åke Strid, Luis Orlando Morales, Victor Costa Castro-Alves, Carolina Falcato Fialho Palma, and Eva Rosenqvist

Subjects
0106 biological sciences, 0301 basic medicine, qL, Trädgårdsvetenskap/hortikultur, Photoinhibition, Photosystem II, total leaf area, transpiration rate, specific leaf mass, Ci, Plant Science, Photosynthetic efficiency, net photosynthetic rate, 01 natural sciences, SLM, Gs, chemistry.chemical_compound, quantum yield or operation ifficiency of PSII, morphology, Pigment accumulation, DM, Chlorophyll fluorescence, Original Research, reactive oxygen species, intracellular CO2 concentration, INL internode lenght, Ø, chlorophyll fluorescence, electron transport rate, fraction of open PSII centres, Biochemistry and Molecular Biology, food and beverages, Dry mass percentage, ROS, LCP, curvature, DM%, CO2, non-photochemical quenching, NPQ, a [morphology 3 Abbreviations], Fv/Fm, TLA, LEDs, Dry mass, light conpensation point, fresh mass, gas exchange, lcsh:Plant culture, Horticulture, Photosynthesis, Fq'/Fm', 03 medical and health sciences, An, individual leaf area, FM, lcsh:SB1-1110, photosynthetically active radiation, stem diameter 4, maximum photochemical efficiency of PSII, leaf mass ratio, UV-B, maximum net assimilation rate, Botany, carbon dioxide, photosystem II, Botanik, LMR, Ultraviolet-B, ILA, Light intensity, apparent quantum yield of photosynthesis, 030104 developmental biology, chemistry, stomatal conductance, Chlorophyll, Biophysics, light quality, PAR, chlorophyll flourescence, Amax, dark respiration, cucumber, ETR, Biokemi och molekylärbiologi, Rdark, 010606 plant biology & botany
Abstract

Ultraviolet B (UV-B, 280 – 315 nm) and ultraviolet A (UV-A, 315-400 nm) radiation comprise small portions of the solar radiation but regulate many aspects of plant development, physiology and metabolism. Until now, how plants respond to UV-B in the presence of different light qualities is poorly understood. This study aimed to assess the effects of a low UV-B dose (0.912± 0.074 kJ m-2 day-1, at a 6 h daily UV exposure) in combination with four light treatments (blue, green, red and broadband white at 210 μmol m-2 s-1 Photosynthetic active radiation [PAR]) on morphological and physiological responses of cucumber (Cucumis sativus cv. ‘Lausanna RZ F1’). We explored the effects of light quality backgrounds on plant morphology, leaf gas exchange, chlorophyll fluorescence, epidermal pigment accumulation, and on acclimation ability to saturating light intensity. Our results showed that supplementary UV-B significantly decreased biomass accumulation in the presence of broad band white, blue and green light, but not under red light. UV‐B also reduced the photosynthetic efficiency of CO2 fixation (α) when combined with blue light. These plants, despite showing high accumulation of anthocyanins, were unable to cope with saturating light conditions. No significant effects of UV-B in combination with green light were observed for gas exchange and chlorophyll fluorescence parameters, but supplementary UV-B significantly increased chlorophyll and flavonol contents in the leaf epidermis. Plants grown under red light and UV-B significantly increased maximum photosynthetic rate and dark respiration compared to pure red light. Additionally, red and UV-B treated plants during with saturating light intensity showed an higher quantum yield of photosystem II (PSII), fraction of open PSII centres and electron transport rate and showed no effect on the apparent maximum quantum efficiency of PSII photochemistry (Fv/Fm) or non-photochemical quenching in contrast to solely red-light conditions. These findings provide new insights into how plants respond to UV-B radiation in the presence of different light spectra., Funding Agencies:GUDP (Danish Ministry of Food, Agriculture and Fisheries) Research center iFood Faculty for Business, Science and Technology at Örebro University Örebro University Vice Chancellor's strategic research programme on 'Food and Health'

Published
2021

2. Phototropins do not alter accumulation of evening-phased circadian transcripts under blue light.

Author

Litthauer S, Battle MW, and Jones MA

Subjects
Arabidopsis radiation effects, Arabidopsis Proteins genetics, Arabidopsis Proteins metabolism, DNA-Binding Proteins genetics, DNA-Binding Proteins metabolism, Light Signal Transduction, Phototropins metabolism, RNA, Messenger, Transcription Factors genetics, Transcription Factors metabolism, Arabidopsis metabolism, Circadian Clocks genetics, Light, Phototropins physiology
Abstract

The circadian system induces rhythmic variation in a suite of biochemical and physiological processes that serve to optimise plant growth in diel cycles. To be of greatest utility, these rhythmic behaviors are coordinated with regular environmental changes such as the rising and setting of the sun. Photoreceptors, along with metabolites produced during photosynthesis, act to synchronise the internal timing mechanism with lighting cues. We have recently shown that phototropins help maintain robust rhythms of photosynthetic operating efficiency (ϕPSII or Fq'/Fm') under blue light, although rhythmic accumulation of morning-phased circadian transcripts in the nucleus was unaffected. Here we report that evening-phased nuclear clock transcripts were also unaffected. We also observe that rhythms of nuclear clock transcript accumulation are maintained in phototropin mutant plants under a fluctuating lighting regime that induced a loss of Fq'/Fm' rhythms.

Published
2016
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results