Plant reageert op korte en lange termijn verschillend op lichtkleur : onderscheid effecten fotosynthese en fotomorfogenese
Ieperen, W. van; Heuvelink, E. ; Kierkels, T. - \ 2016
Onder Glas 13 (2016)10. - p. 15 - 17.
kunstlicht - fotosynthese - plantenontwikkeling - fotomorfogenese - proefopzet - fotosynthetische actieve straling - belichting - glastuinbouw - artificial light - photosynthesis - plant development - photomorphogenesis - experimental design - photosynthetically active radiation - illumination - greenhouse horticulture
De inzichten in het effect van lichtkleuren op fotosynthese, vorm en ontwikkeling groeien gestaag. Je zou dan graag willen dat het om simpele relaties gaat, bijvoorbeeld ‘blauw licht opent huidmondjes’. Zo ligt het echter vaak niet. Effecten op korte en lange termijn zijn vaak verschillend en het gaat altijd om de mix van kleuren.
Striga hermonthica MAX2 restores branching but not the Very Low Fluence Response in the Arabidopsis thaliana max2 mutant
Liu, Q. ; Zhang, Y. ; Matusovaa, R. ; Charnikhova, T. ; Amini, M. ; Jamil, M. ; Fernandez-Aparicio, M. ; Huang, K. ; Timko, M.P. ; Westwood, J.H. ; Ruyter-Spira, C.P. ; Krol, A.R. van der; Bouwmeester, H.J. - \ 2014
New Phytologist 202 (2014)2. - ISSN 0028-646X - p. 531 - 541.
arabidopsis seed-germination - box protein max2 - plant hormone - strigolactone - inhibition - photomorphogenesis - stimulants - karrikins - molecule - pathway
Seed germination of Striga spp. (witchweeds), one of the world’s most destructive parasitic weeds, cannot be induced by light but is specifically induced by strigolactones. It is not known whether Striga uses the same components for strigolactone signaling as host plants, whether it has endogenous strigolactone biosynthesis and whether there is post-germination strigolactone signaling in Striga. Strigolactones could not be detected in in vitro grown Striga, while for host-grown Striga, the strigolactone profile is dominated by a subset of the strigolactones present in the host. Branching of in vitro grown Striga is affected by strigolactone biosynthesis inhibitors. ShMAX2, the Striga ortholog of Arabidopsis MORE AXILLARY BRANCHING 2 (AtMAX2) – which mediates strigolactone signaling – complements several of the Arabidopsis max2-1 phenotypes, including the root and shoot phenotype, the High Irradiance Response and the response to strigolactones. Seed germination of max2-1 complemented with ShMAX2 showed no complementation of the Very Low Fluence Response phenotype of max2-1. Results provide indirect evidence for ShMAX2 functions in Striga. A putative role of ShMAX2 in strigolactone-dependent seed germination of Striga is discussed.
On the photosynthetic and devlopmental responses of leaves to the spectral composition of light
Hogewoning, S.W. - \ 2010
Wageningen University. Promotor(en): Olaf van Kooten, co-promotor(en): Jeremy Harbinson; Wim van Ieperen. - [S.l. : S.n. - ISBN 9789085857990 - 140
cucumis sativus - fotosynthese - kunstlicht - spectraalanalyse - fotomorfogenese - plantenontwikkeling - fotosysteem i - fotosysteem ii - lichtgevende dioden - cucumis sativus - photosynthesis - artificial light - spectral analysis - photomorphogenesis - plant development - photosystem i - photosystem ii - light emitting diodes
Key words: action spectrum, artificial solar spectrum, blue light, Cucumis sativus, gas-exchange, light-emitting diodes (LEDs), light interception, light quality, non-photosynthetic pigments, photo-synthetic capacity, photomorphogenesis, photosystem excitation balance, quantum yield, red light.
A wide range of plant properties respond to the spectral composition of irradiance, such as photosynthesis, photomorphogenesis, phototropism and photonastic movements. These responses affect plant productivity, mainly via changes in the photosynthetic rate per unit leaf area, light interception, and irradiance distribution through the canopy. The spectral environment of plants is dependent on location (e.g. latitude), changes over time (e.g. Sun-angle), shading by other leaves, and, in the case of protected cultivation, the use of growth lamps. Therefore, not only the acclimation of developing leaves to light spectrum is important for plant productivity and survival, but also the capability of mature leaves to respond to changes in spectrum. This thesis focuses on the acclimation of photosynthesis per unit leaf area to the growth-light spectrum, the consequences of spectral acclimation for the wavelength dependence of photosynthetic quantum yield, and photomorphogenetic versus leaf photosynthetic acclimation in relation to biomass production. Cucumis sativus is used as a model plant. Additionally, the consequences of the choice and quality of the actinic light used during photosynthesis measurements are explored.
By growing plants under seven different combinations of red and blue light, blue light is shown to have both a qualitative and a quantitative effect on leaf development. Only leaves developed under red alone (0% blue) displayed a dysfunctional photosynthetic operation, which was largely alleviated by only 7% blue. Quantitatively, leaf responses to an increasing blue light percentage resembled responses associated with an increase in irradiance.
Next, the wavelength dependence of the quantum yield for CO2 fixation (α) is analysed in detail. Leaves grown under artificial shadelight, which overexcites photosystem I (PSI), had a higher α at wavelengths overexciting PSI (≥690 nm) and a lower PSI:PSII ratio compared with artificial sunlight and blue light grown leaves. At wavelengths overexciting PSII, α of the sun and blue grown leaves was higher. The photosystem excitation balance is quantitatively shown to determine α at those wavelengths where absorption by carotenoids and non-photosynthetic pigments is insignificant (≥580 nm). The wavelength dependences of the photosystem excitation balance calculated via an in vivo and an in vitro approach were substantially in agreement with each other, and where not, carotenoid absorption and state transitions are likely to play a role.
Not only is the photosynthetic rate per unit leaf area is important for plant productivity, but also photomorphogenesis. We have engineered an artificial solar (AS) spectrum under which plants produced a dry weight that was, respectively, 2.3 and 1.6 times greater than that of plants grown under fluorescent tubes and high pressure sodium light. This striking difference was due to a morphology of the AS-plants that was more efficient in light interception, and not related to photosynthesis per unit leaf area. These results highlight the importance of a spectrum that is more natural than that of usual growth-lamps for research and possibly also for horticultural production.
A technically orientated part of this thesis presents a simple method to quantify the light distribution in leaf chambers, which is shown to be important for the accuracy of photosynthesis measurements by gas-exchange. The match between growth-light and measuring-light spectrum is likewise shown to be important. A mismatch can have significant consequences for the estimate of α in situ, but only minor consequences for the estimate of the light-saturated photosynthetic rate. The relationship between the electron transport rate calculated using chlorophyll fluorescence measurements and the CO2 fixation rate also changed considerably with changes in measuring-light spectrum. The use of erroneous estimates of α as input for crop growth models is shown to have disproportionately large consequences for predictions of plant growth.
An artificial solar spectrum substantially alters plant development compared with usual climate room irradiance spectra
Hogewoning, S.W. ; Douwstra, P. ; Trouwborst, G. ; Ieperen, W. van; Harbinson, J. - \ 2010
Journal of Experimental Botany 61 (2010)5. - ISSN 0022-0957 - p. 1267 - 1276.
light-emitting-diodes - chenopodium-album l - far-red ratio - blue-light - supplemental blue - leaf formation - quality red - green light - growth - photomorphogenesis
Plant responses to the light spectrum under which plants are grown affect their developmental characteristics in a complicated manner. Lamps widely used to provide growth irradiance emit spectra which are very different from natural daylight spectra. Whereas specific responses of plants to a spectrum differing from natural daylight may sometimes be predictable, the overall plant response is generally difficult to predict due to the complicated interaction of the many different responses. So far studies on plant responses to spectra either use no daylight control or, if a natural daylight control is used, it will fluctuate in intensity and spectrum. An artificial solar (AS) spectrum which closely resembles a sunlight spectrum has been engineered, and growth, morphogenesis, and photosynthetic characteristics of cucumber plants grown for 13 d under this spectrum have been compared with their performance under fluorescent tubes (FTs) and a high pressure sodium lamp (HPS). The total dry weight of the AS-grown plants was 2.3 and 1.6 times greater than that of the FT and HPS plants, respectively, and the height of the AS plants was 4–5 times greater. This striking difference appeared to be related to a more efficient light interception by the AS plants, characterized by longer petioles, a greater leaf unfolding rate, and a lower investment in leaf mass relative to leaf area. Photosynthesis per leaf area was not greater for the AS plants. The extreme differences in plant response to the AS spectrum compared with the widely used protected cultivation light sources tested highlights the importance of a more natural spectrum, such as the AS spectrum, if the aim is to produce plants representative of field conditions
The light-hyperresponsive high pigment-2dg mutation of tomato: alterations in the fruit metabolome
Bino, R.J. ; Vos, C.H. de; Lieberman, M. ; Hall, R.D. ; Bovy, A.G. ; Jonker, H.H. ; Tikunov, Y.M. ; Lommen, A. ; Moco, S.I.A. ; Levin, I. - \ 2005
New Phytologist 166 (2005)2. - ISSN 0028-646X - p. 427 - 438.
physiological characterization - high-pigment-1 mutant - signal-transduction - photosystem-ii - plant - quality - photomorphogenesis - phenotype - genotypes - homolog
Overall metabolic modifications between fruit of light-hyperresponsive high-pigment (hp) tomato (Lycopersicon esculentum) mutant plants and isogenic nonmutant (wt) control plants were compared. Targeted metabolite analyses, as well as large-scale nontargeted mass spectrometry (MS)-based metabolite profiling, were used to phenotype the differences in fruit metabolite composition. Targeted high-performance liquid chromatography with photodiode array detection (HPLC-PDA) metabolite analyses showed higher levels of isoprenoids and phenolic compounds in hp-2(dg) fruit. Nontargeted GC-MS profiling of red fruits produced 25 volatile compounds that showed a 1.5-fold difference between the genotypes. Analyses of red fruits using HPLC coupled to high-resolution quadrupole time-of-flight mass spectrometry (LC-QTOF-MS) in both ESI-positive and ESI-negative mode generated, respectively, 6168 and 5401 mass signals, of which 142 and 303 showed a twofold difference between the genotypes. hp-2(dg) fruits are characterized by overproduction of many metabolites, several of which are known for their antioxidant or photoprotective activities. These metabolites may now be more closely implicated as resources recruited by plants to respond to and manage light stress. The similarity in metabolic alterations in fruits of hp-1 and hp-2 mutant plants helps us to understand how hp mutations affect cellular processes.
The degradation of HFR1, a putative bHLH class transcription factor involved in light signaling, is regulated by phosphorylation and requires COP1
Duek, P.D. ; Elmer, M.V. ; Oosten, V.R. van; Fankhauser, C. - \ 2004
Current Biology 14 (2004)24. - ISSN 0960-9822 - p. 2296 - 2301.
loop-helix protein - phytochrome-a - arabidopsis cryptochromes - branch pathway - factor family - hy5 - photomorphogenesis - ubiquitination - thaliana - binding
All developmental transitions throughout the life cycle of a plant are influenced by light. In Arabidopsis, multiple photoreceptors including the UV-A/blue-sensing cryptochromes (cry1-2) and the red/far-red responsive phytochromes (phyA-E) monitor the ambient light conditions [1 and 2]. Light-regulated protein stability is a major control point of photomorphogenesis . The ubiquitin E3 ligase COP1 (nstitutively hotomorphogenic 1) regulates the stability of several light-signaling components [4, 5 and 6]. HFR1 (long ypocotyl in ar-ed light) is a putative transcription factor with a bHLH domain acting downstream of both phyA and the cryptochromes [7, 8 and 9]. HFR1 is closely related to PIF1, PIF3, and PIF4 (hytochrome nteracting actor 1, 3 and 4), but in contrast to the latter three, there is no evidence for a direct interaction between HFR1 and the phytochromes [7, 10, 11 and 12]. Here, we show that the protein abundance of HFR1 is tightly controlled by light. HFR1 is an unstable phosphoprotein, particularly in the dark. The proteasome and COP1 are required in vivo to degrade phosphorylated HFR1. In addition, HFR1 can interact with COP1, consistent with the idea of COP1 directly mediating HFR1 degradation. We identify a domain, conserved among several bHLH class proteins involved in light signaling [13 and 14], as a determinant of HFR1 stability. Our physiological experiments indicate that the control of HFR1 protein abundance is important for a normal de-etiolation response