| 1. |
- Landberg, Tommy, et al.
(författare)
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No phytochelatin (PC2 and PC3) detected in Salix viminalis
- 2004
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 121:3, s. 481-487
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Tidskriftsartikel (refereegranskat)abstract
- Phytochelatins (PCs) have been detected in a large range of plant species, but their role in heavy-metal tolerance is unclear. Various clones of Salix viminalis are differently tolerant to heavy metals, and the aim of this work was to investigate whether PCs were differently expressed in tolerant compared with sensitive clones. In a long-term study, five clones with high or low metal tolerance were cultivated 21 days without or with Cd (1 or 10 µM), Cu (0.3 or 7 µM), Ni (15 µM), Pb (7 µM) or Zn (10 or 100 µM). Controls were further used in a short-term study where Cd (1 µM) was added and samples were collected 0, 15 and 30 min, 1, 3 and 24 h after start of treatment. PCs were analysed on high performance liquid chromatography (HPLC) using two different methods: post-column derivatization using Ellmans reagent and pre-derivatization with monobromobimane. Thlaspi caerulescens treated with Cd was used as internal PC standard. No PCs could be detected in Salix with either of the two methods in any of the treatments: different clones, metals, concentrations, plant parts or treatment time. The 16 thiol peaks shown were the same in both control and treated plants. Both HPLC methods showed PC peaks when Thlaspi was used but these peaks could not be associated with any of the 16 peaks. The amino acid composition of the 16 peaks was not the expected composition of that of PCs. Thus, Salix viminalis have no detectable levels of PCs, which in turn are not involved in heavy metal tolerance in Salix
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| 2. |
- Noren, H, et al.
(författare)
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A convenient and versatile hydroponic cultivation system for Arabidopsis thaliana
- 2004
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 121:3, s. 343-348
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Tidskriftsartikel (refereegranskat)abstract
- A versatile two-step cultivation procedure for Arabidopsis thaliana is described for the production of large quantities of leaf material suitable for biochemical and biophysical analysis. The first step comprises a miniature greenhouse made out of a plastic pipette box to grow the seedlings to the six-leaf stage. For continued growth, the seedlings are transferred to hydroponic cultivation using an opaque container covered by a styrofoam lid. Transfer of the small seedlings to hydroponic culture is facilitated by growth in separate pipette tips, which protects vulnerable roots from damage. The hydroponic cultivation system is easy to scale-up and produces large amounts of relatively large leaves and roots. This hydroponic system produces enough plant material to make Arabidopsis a feasible model for biochemical and biophysical experiments, which can be combined with the available genetic information to address various aspects of plant functional genomics
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| 3. |
- Solymosi, K., et al.
(författare)
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Plastid differentiation and chlorophyll biosynthesis in different leaf layers of white cabbage (Brassica oleracea cv. capitata)
- 2004
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 121:3, s. 520-529
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Tidskriftsartikel (refereegranskat)abstract
- The contents of protochlorophyllide, protochlorophyll and chlorophyll together with the native arrangements of the pigments and the plastid ultrastructure were studied in different leaf layers of white cabbage (Brassica oleracea cv. capitata) using absorption, 77 K fluorescence spectroscopy and transmission electron microscopy. The developmental stage of the leaves was determined using the differentiation of the stoma complexes as seen by scanning electron microscopy and light microscopy. The pigment content showed a gradual decrease from the outer leaf layer towards the central leaves. The innermost leaves were in a primordial stage in many aspects; they were large but had typical proplastids with few simple inner membranes, and contained protochlorophyllide and its esters in a 2 : 1 ratio and no chlorophyll. Short-wavelength, not flash-photoactive protochlorophyllide and/or protochlorophyll forms emitting at 629 and 636 nm were dominant in the innermost leaves. These leaves also had small amounts of the 644 and 654 nm emitting, flash-photoactive protochlorophyllide forms. Rarely prolamellar bodies were observed in this layer. The outermost leaves had the usual characteristics of fully developed green leaves. The intermediary layers contained chlorophyll a and chlorophyll b besides the protochlorophyll(ide) pigments and had various intermediary developmental stages. Spectroscopically two types of intermediary leaves could be distinguished: one with only a 680 nm emitting chlorophyll a form and a second with bands at 685, 695 and 730 nm, corresponding to chlorophyll-protein complexes of green leaves. In these leaves, a large variety of chloroplasts were found. The data of this work show that etioplasts, etio-chloroplasts or chloro-etioplasts as well as etiolated leaves do exist in the nature and not only under laboratory conditions. The specificity of cabbage leaves compared with those of dark-grown seedlings is the retained primordial or intermediary developmental stage of leaves in the inner layers for very long (even for a few month) period. This opens new developmental routes leading to formation of specially developed plastids in the various cabbage leaf layers. The study of these plastids provided new information for a better understanding of the plastid differentiation and the greening process.
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| 4. |
- Abdelkader, Amal F., 1969, et al.
(författare)
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High salt stress in wheat leaves causes retardation of chlorophyll accumulation due to a limited rate of protochlorophyllide formation
- 2007
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 130:1, s. 157-166
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Tidskriftsartikel (refereegranskat)abstract
- When exposed to salt stress, leaves from dark-grown wheat seedlings (Triticum aestivum, cv. Giza 168) showed reduced accumulation of chlorophyll during irradiation. To elucidate the mechanism behind salt-influenced reduction of chlorophyll biosynthesis, we have investigated the effect of salt stress on the spectral forms of Pchlide, the phototransformation of Pchlide to Chlide, the Shibata shift, the regeneration of Pchlide and the accumulation of Pchlide from 5-aminolevulinic acid (ALA). We found that the phototransformation of Pchlide to Chlide was not affected by salt stress. The blue shift (Shibata shift) of newly formed Chlide was delayed both after flash irradiation and in continuous light. The reformation of Pchlide in darkness after a flash irradiation or after a period of 3-h irradiation was retarded in the salt-treated leaves. However, after a 20-h dark period, Pchlide was reformed even in salt-treated leaves but the formation of short-wavelength Pchlide was suppressed. Compared to controls, salt treatment also reduced the amount of Pchlide accumulated in leaves floated on ALA. The increase in the low temperature fluorescence emission spectrum at 735 nm, which occurred gradually during several hours of irradiation with continuous light in control leaves, was completely suppressed in salt-treated leaves. It is concluded that salt stress inhibits chlorophyll accumulation partly by reducing the rate of porphyrin formation but, as discussed, also by a possible reduction in the formation of chlorophyll-binding proteins.
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| 5. |
- Agius, Stephanie C, et al.
(författare)
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The internal rotenone-insensitive NADPH dehydrogenase contributes to malate oxidation by potato tuber and pea leaf mitochondria
- 1998
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317. ; 104:3, s. 329-336
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Tidskriftsartikel (refereegranskat)abstract
- Inside-out submitochondrial particles from both potato (Solanum tuberosum L. cv. Bintje) tubers and pea (Pisum sativum L. cv. Oregon) leaves possess three distinct dehydrogenase activities: Complex I catalyzes the rotenone-sensitive oxidation of deamino-NADH, NDin(NADPH) catalyzes the rotenone-insensitive and Ca2+-dependent oxidation of NADPH and NDin(NADH) catalyzes the rotenone-insensitive and Ca2+-independent oxidation of NADH. Diphenylene iodonium (DPI) inhibits complex I, NDin(NADPH) and NDin (NADH) activity with a Ki of 3.7, 0.17 and 63 µM, respectively, and the 400-fold difference in Ki between the two NDin made possible the use of DPI inhibition to estimate NDin (NADPH) contribution to malate oxidation by intact mitochondria. The oxidation of malate in the presence of rotenone by intact mitochondria from both species was inhibited by 5 µM DPI. The maximum decrease in rate was 10–20 nmol O2 mg-1 min-1. The reduction level of NAD(P) was manipulated by measuring malate oxidation in state 3 at pH 7.2 and 6.8 and in the presence and absence of an oxaloacetate-removing system. The inhibition by DPI was largest under conditions of high NAD(P) reduction. Control experiments showed that 125 µM DPI had no effect on the activities of malate dehydrogenase (with NADH or NADPH) or malic enzyme (with NAD+ or NADP+) in a matrix extract from either species. Malate dehydrogenase was unable to use NADP+ in the forward reaction. DPI at 125 µM did not have any effect on succinate oxidation by intact mitochondria of either species. We conclude that the inhibition caused by DPI in the presence of rotenone in plant mitochondria oxidizing malate is due to inhibition of NDin(NADPH) oxidizing NADPH. Thus, NADP turnover contributes to malate oxidation by plant mitochondria.
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| 6. |
- Albertsson, Per-Åke, et al.
(författare)
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The constant proportion of grana and stroma lamellae in plant chloroplasts
- 2004
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Ingår i: Physiologia Plantarum. - 0031-9317. ; 121:2, s. 334-342
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Tidskriftsartikel (refereegranskat)abstract
- The relative proportion of stroma lamellae and grana end membranes was determined from electron micrographs of 58 chloroplasts from 21 different plant species. The percentage of grana end membranes varied between 1 and 21% of the total thylakoid membrane indicating a large variation in the size of grana stacks. By contrast the stroma lamellae account for 20.3 +/- 2.5 (SD)% of the total thylakoid membrane. A plot of percentage stroma lamellae against percentage of grana end membranes fits a straight line with a slope of zero showing that the proportion of stroma lamellae is independent of the size of the grana stacks. That stroma lamellae account for about 20% of the thylakoid membrane is in agreement with fragmentation and separation analysis (Gadjieva et al. Biochim. Biophys. Acta 144: 92-100, 1999). Chloroplasts from spinach, grown under high or low light, were fragmented by sonication and separated by countercurrent distribution into two vesicle populations originating from grana and stroma lamellae plus end membranes, respectively. The separation diagrams were very similar lending independent support for the notion that the proportion of stroma lamellae is constant. The results are discussed in relation to the composition and function of the chloroplast in plants grown under different environmental conditions, and in relation to a recent quantitative model for the thylakoid (Albertsson, Trends Plant Sci. 6: 349-354, 2001).
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| 7. |
- Allahverdiyeva, Yagut, et al.
(författare)
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NordAqua, a Nordic Center of Excellence to develop an algae-based photosynthetic production platform
- 2021
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Ingår i: Physiologia Plantarum. - : John Wiley & Sons. - 0031-9317 .- 1399-3054. ; 173:2, s. 507-513
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Tidskriftsartikel (refereegranskat)abstract
- NordAqua is a multidisciplinary Nordic Center of Excellence funded by NordForsk Bioeconomy program (2017–2022). The research center promotes Blue Bioeconomy and endeavours to reform the use of natural resources in a environmentally sustainable way. In this short communication, we summarize particular outcomes of the consortium. The key research progress of NordAqua includes (1) improving of photosynthetisis, (2) developing novel photosynthetic cell factories that function in a “solar-driven direct CO2 capture to target bioproducts” mode, (3) promoting the diversity of Nordic cyanobacteria and algae as an abundant and resilient alternative for less sustainable forest biomass and for innovative production of biochemicals, and (4) improving the bio-based wastewater purification and nutrient recycling technologies to provide new tools for integrative circular economy platforms.
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| 8. |
- Amirjani, M. R., et al.
(författare)
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Protochlorophyllide and POR development in dark-grown plants with different proportions of short-wave length and long-wavelength protochlorophyllide spectral forms
- 2006
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 128:4, s. 751-762
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Tidskriftsartikel (refereegranskat)abstract
- The effect of leaf developmental age on the protochlorophyllide (Pchlide) spectral forms and the expression of messenger RNA (mRNA) encoding NADPH-protochlorophyllide oxidoreductase (POR) were investigated. Four plant species, maize, wheat, pea and the lip 1 mutant of pea, known to have different composition of the spectral forms of Pchlide, were used. In very young plants short-wavelength Pchlide with a fluorescence emission at 631 nm was dominating. Long-wavelength Pchlide fluorescing mainly around 655 nm increased during development, which led to a relative decrease of the short-wavelength forms. During ageing of the leaves, the short-wavelength forms slightly increased again. The different proportions of short- and long-wavelength Pchlide spectral forms were, however, found to vary with the developmental stage in a species specific pattern. The steady-state level of POR mRNA and the amount of the POR protein were similar in species dominated by short-wavelength forms and in species dominated with long-wavelength forms. Even if POR is necessary for the formation of the long-wavelength Pchlide form it is not the only limiting factor for formation of long-wavelength Pchlide forms in mature plants.
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| 9. |
- Amirjani, M. R., et al.
(författare)
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Regeneration of protochlorophyllide in green and greening leaves of plants with varying proportions of protochlorophyllide forms in darkness
- 2004
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 121:3, s. 377-390
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Tidskriftsartikel (refereegranskat)abstract
- During illumination of dark-grown plants protochlorophyllide (Pchlide) is continuously transformed to chlorophyllide (Chlide). Different dark-grown plants, maize (Zea mays cv. Sundance), wheat (Triticum aestivum cv. Kosack), pea (Pisum sativum cv. Kelwedon wonder), the lip1 mutant of pea, and the aurea mutant of tomato (Solanum lycopersicum), have various ratios of spectral Pchlide forms in darkness. When the plants were illuminated and then returned to darkness Pchlide re-accumulated. The proportions of different Pchlide forms within the pool of re-accumulated Pchlide were followed by low temperature fluorescence emission and excitation spectra in green and greening leaves. After 1 h of illumination the spectral characteristics of regenerated Pchlide forms mirrored those of Pchlide in dark-grown plants and were thus species dependent. After a prolonged illumination period (24 h) as well as in fully green leaves energy transfer to chlorophyll (Chl) masked the presence of long-wavelength Pchlide in the fluorescence emission spectra. However, excitation spectra showed Pchlide absorption around 650 nm and its flash-induced disappearance confirmed its nature of phototransformable Pchlide. In fact the excitation spectra showed that the proportions of different Pchlide forms in green leaves highly resembled the proportions of Pchlide forms in dark-grown leaves and were specific for the plant variety. Thus Chl formation in both dark-grown and light-grown leaves can occur in a similar way through the main photoactive long-wavelength form of Pchlide.
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| 10. |
- Andersson, Mariette, et al.
(författare)
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Genome editing in potato via CRISPR-Cas9 ribonucleoprotein delivery
- 2018
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Ingår i: Physiologia Plantarum. - : Wiley. - 0031-9317 .- 1399-3054. ; 164, s. 378-384
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Tidskriftsartikel (refereegranskat)abstract
- Clustered regularly interspaced short palindromic repeats and CRISPR-associated protein-9 (CRISPR-Cas9) can be used as an efficient tool for genome editing in potato (Solanum tuberosum). From both a scientific and a regulatory perspective, it is beneficial if integration of DNA in the potato genome is avoided. We have implemented a DNA-free genome editing method, using delivery of CRISPR-Cas9 ribonucleoproteins (RNPs) to potato protoplasts, by targeting the gene encoding a granule bound starch synthase (GBSS, EC 2.4.1.242). The RNP method was directly implemented using previously developed protoplast isolation, transfection and regeneration protocols without further adjustments. Cas9 protein was preassembled with RNA produced either synthetically or by in vitro transcription. RNP with synthetically produced RNA (cr-RNP) induced mutations, i.e. indels, at a frequency of up to 9%, with all mutated lines being transgene-free. A mutagenesis frequency of 25% of all regenerated shoots was found when using RNP with in vitro transcriptionally produced RNA (IVT-RNP). However, more than 80% of the shoots with confirmed mutations had unintended inserts in the cut site, which was in the same range as when using DNA delivery. The inserts originated both from DNA template remnants from the in vitro transcription, and from chromosomal potato DNA. In 2-3% of the regenerated shoots from the RNP-experiments, mutations were induced in all four alleles resulting in a complete knockout of the GBSS enzyme function.
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