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  • Tausz, Michael  (41)
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  • 1
    Language: English
    In: Journal of plant physiology, March 2004, Vol.161(3), pp.347-9
    Description: The most abundant thiol in beans (Phaseolus vulgaris L. cv. Saxa) is the tripeptide homoglutathione (hGSH) rather than glutathione (GSH). At the whole-plant level the GSH content is less than 0.5% of the hGSH content. In the present study GSH was supplied to the roots of bean seedlings to test whether GSH can be taken up by roots and transported to the shoot. Therefore, 12-day-old plants were exposed to 1 mmol/L GSH for 4, 8 and 24 h prior to harvest. In response to this GSH exposure, elevated GSH contents were found in all tissues. After 4 h the GSH content increased in the roots from 1 +/- 1 to 22 +/- 2 nmol GSH g(-1) fresh weight (FW), in the leaves from 2 +/- 1 to 9 +/- 4 nmol GSH g(-1) FW, and in the apex from 30 +/- 5 to 75 +/- 4 nmol GSH g(-1) FW. These data indicate that GSH is taken up by bean roots and is transported to above above-ground parts of the plants. Roots exposed to GSH for 24 h contained 2-fold higher cysteine (Cys) and hGSH contents than the controls. Apparently, GSH taken up by the roots is not only loaded into the xylem but also partially degraded and used for hGSH synthesis.
    Keywords: Glutathione -- Metabolism ; Phaseolus -- Metabolism
    ISSN: 0176-1617
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  • 2
    In: New Phytologist, October 2012, Vol.196(1), pp.162-172
    Description: • Increasing atmospheric concentrations of phytotoxic ozone (O3) can constrain growth and carbon sink strength of forest trees, potentially exacerbating global radiative forcing. Despite progress in the conceptual understanding of the impact of O3 on plants, it is still difficult to detect response patterns at the leaf level. • Here, we employed principal component analysis (PCA) to analyse a database containing physiological leaf‐level parameters of 60‐yr‐old Fagus sylvatica (European beech) trees. Data were collected over two climatically contrasting years under ambient and twice‐ambient O3 regimes in a free‐air forest environment. • The first principal component (PC1) of the PCA was consistently responsive to O3 and crown position within the trees over both years. Only a few of the original parameters showed an O3 effect. PC1 was related to parameters indicative of oxidative stress signalling and changes in carbohydrate metabolism. PC1 correlated with cumulative O3 uptake over preceding days. • PC1 represents an O3‐responsive multivariate pattern detectable in the absence of consistently measurable O3 effects on individual leaf‐level parameters. An underlying effect of O3 on physiological processes is indicated, providing experimental confirmation of theoretical O3 response patterns suggested previously.
    Keywords: Cumulative O 3 Uptake ; Fagus Sylvatica European Beech ; Multivariate Analysis ; Ozone O 3 ; Principal Component Analysis Pca
    ISSN: 0028-646X
    E-ISSN: 1469-8137
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  • 3
    Language: English
    In: Environmental and Experimental Botany, August 2017, Vol.140, pp.1-7
    Description: Nitrogen (N) input into food production is environmentally sensitive and economically significant, making efficient N use an important goal in agricultural practice and in plant breeding. In cereals, grain N concentration [N] is an important component of grain quality and nutritional value. Increasing atmospheric CO concentration [CO ] will not only stimulate growth and yield but also diminish grain [N], raising concerns about product quality and nutritional value. In this study we investigated how differences in root structure and function and agronomic properties between two bread wheat ( L.) cultivars affect N uptake and allocation to grains in a low rainfall environment, and whether such differences can indicate strategies to mitigate grain [N] decreases under increased [CO ]. Two cultivars (‘Silverstar’ and ‘Yitpi’) were chosen for their similar phenology and yields, but ‘Silverstar’ often has lower grain [N]. A glasshouse experiment showed contrasting root structure and function strategies between the two cultivars in response to soil N: ‘Yitpi’ but not ‘Silverstar’ responded to lower soil N with increased root growth, whereas ‘Silverstar’ but not ‘Yitpi’ showed increased N uptake per unit root mass in response to lower N. When grown in the Australian Grains Free Air CO Enrichment facility over multiple seasons both cultivars produced similar yields, but ‘Silverstar’ had consistently lower grain [N], smaller grains and greater harvest index. N uptake measurements with N label showed that wheat roots can take up nitrate, ammonium and glutamine, and also confirmed differences in uptake strategies between cultivars: ‘Silverstar’ roots had significantly greater uptake capacity than ‘Yitpi’ roots for ammonium. Whilst these results suggest that different strategies in response to variations in soil N supply could be related to grain N outcomes at this field site, there was no interaction with atmospheric [CO ] for any of the measured parameters. Regardless of cultivar, elevated [CO ] (550 μmol mol ) increased yields and decreased grain [N], but did not affect root uptake capacities for either N form. Contrasting root uptake strategies seem unrelated to grain [N] decrease under elevated [CO ], at least for this site.
    Keywords: Wheat ; Elevated Co2 ; Grain Protein ; Nitrogen Uptake ; Roots ; FACE ; Environmental Sciences ; Botany
    ISSN: 0098-8472
    E-ISSN: 1873-7307
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  • 4
    In: New Phytologist, January 2002, Vol.153(1), pp.73-80
    Description: •  Sulphur export and redistribution from the cotyledons of pea (Pisum sativum) seedlings was investigated to determine the role of cotyledons as a sulphur source during root–shoot axis development. •  Thiols and sulphate were analysed using standard biochemical techniques, and 35S fed to cotyledons by injection. •  After 35S‐cysteine injection, c. 50% of the labelled S in the cotyledon was metabolized to 35S‐sulphate. This reaction was partly inhibited by aminooxyacetic acid, an inhibitor of cysteine‐desulfhydrase. After 35S‐sulphate application, c. 1% of the radiolabel was found in cysteine and glutathione in the cotyledon. After 2 h, c. 20% of the 35S was transported into the root–shoot axis independently of whether 35S‐sulphate or 35S‐cysteine was injected into the cotyledon. After 4 h, 40% of 35S was found outside the cotyledon. •  Cotyledons of pea seedlings are capable of sulphate assimilation and cysteine degradation. Both sulphate and reduced sulphur were allocated from the cotyledons to the developing tissues of the pea seedlings.
    Keywords: Cotyledon ; Cysteine ; Glutathione ; Pea ; Storage Tissue ; Sulphate ; Sulphur
    ISSN: 0028-646X
    E-ISSN: 1469-8137
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  • 5
    Conference Proceeding
    Conference Proceeding
    Springer Netherlands, Dordrecht
    Language: English
    Keywords: Life Sciences -- Plant Sciences; Life Sciences -- Plant Physiology; Life Sciences -- Plant Biochemistry; Life Sciences -- Agriculture; Life Sciences -- Plant Ecology; Life Sciences -- Climate Change
    ISBN: 978-94-007-4449-3
    Source: Springer Science & Business Media B.V.
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  • 6
    Language: English
    In: Proceedings of the International Plant Sulfur Workshop, Sulfur Metabolism in Plants: Mechanisms and Applications to Food Security and Responses to Climate Change, pp.203-215
    Description: Plants interact with sulfur in two different ways. As a macronutrient sulfur is needed for growth and development; at the same time, sulfur is an important substrate and reductant during various forms of stresses mediated by the abiotic environment. The use of sulfur compounds as substrate and/or reductant in compensation reactions of abiotic stresses including oxidative stress, heavy metal and xenobiotic exposure is discussed with special emphasis on the S-containing tri-peptide glutathione (GSH). The examples shown indicate that individual components of S metabolism are involved in different processes of abiotic stress compen‑sation. In the present review the current knowledge of GSH (i) as reductant in the compensation of oxidative stress, (ii) as reductant as well as a substrate in redox reactions, (iii) its direct and indirect involvement in posttranscriptional modification reactions, and (iv) its constitution as a substrate for chelating heavy metals and for conjugation of xenobiotic is discussed. Competition with plant development and growth is also considered.
    Keywords: Life Sciences ; Plant Sciences ; Plant Physiology ; Plant Biochemistry ; Agriculture ; Plant Ecology ; Climate Change ; Agriculture ; Botany
    ISBN: 9789400744493
    ISBN: 9400744498
    Source: SpringerLink Books
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  • 7
    Language: English
    In: Tree physiology, May 2008, Vol.28(5), pp.713-9
    Description: We quantified ascorbate, glutathione and alpha-tocopherol in fine roots of mature Fagus sylvatica L. under free-air canopy ozone (O(3)) exposure (twice ambient O(3) concentration, 2x[O(3)]) during two growing seasons that differed in the extent of summer drought (exceptional drought year 2003, average year 2004). This design allowed us to test whether O(3) exposure or drought, or both, affected root antioxidants during the growing season. In both years, root ascorbate and alpha-tocopherol showed a similar relationship with volumetric soil water content (SWC): ascorbate concentrations on a root dry mass basis increased from about 6 to 12 micromol g(-1) when SWC dropped from 25 to 20%, and a-tocopherol increased from 100 to 150 nmol g(-1) at SWC values below 20%. Root glutathione showed no relationship with SWC or differences between the dry and the average year, but it was significantly and consistently diminished by 2x[O(3)]. Our results were inconclusive as to whether shoot-root translocation of glutathione or glutathione production in the roots was diminished. Phloem glutathione concentrations in the canopy remained constant, but reduced transport velocity in the phloem and, as a consequence, reduced mass flow of glutathione cannot be ruled out.
    Keywords: Disasters ; Antioxidants -- Metabolism ; Fagus -- Drug Effects ; Ozone -- Pharmacology ; Plant Roots -- Drug Effects
    ISSN: 0829-318X
    E-ISSN: 17584469
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  • 8
    In: Tree Physiology, 2008, Vol. 28(5), pp.713-719
    Description: Fagus sylvatica 3 3 3 3 −1 −1 3 We quantified ascorbate, glutathione and α-tocopherol in fine roots of mature Fagus sylvatica L. under free-air canopy ozone (O 3 ) exposure (twice ambient O 3 concentration, 2×[O 3 ]) during two growing seasons that differed in the extent of summer drought (exceptional drought year 2003, average year 2004). This design allowed us to test whether O 3 exposure or drought, or both, affected root antioxidants during the growing season. In both years, root ascorbate and α-tocopherol showed a similar relationship with volumetric soil water content (SWC): ascorbate concentrations on a root dry mass basis increased from about 6 to 12 μmol g −1 when SWC dropped from 25 to 20%, and a-tocopherol increased from 100 to 150 nmol g −1 at SWC values below 20%. Root glutathione showed no relationship with SWC or differences between the dry and the average year, but it was significantly and consistently diminished by 2×[O 3 ]. Our results were inconclusive as to whether shoot–root translocation of glutathione or glutathione production in the roots was diminished. Phloem glutathione concentrations in the canopy remained constant, but reduced transport velocity in the phloem and, as a consequence, reduced mass flow of glutathione cannot be ruled out.
    Keywords: Ascorbate ; Glutathione ; Mycorrhiza ; Oxidative Stress ; Α - Tocopherol
    ISSN: 0829-318X
    E-ISSN: 1758-4469
    Source: Oxford University Press
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  • 9
    Language: English
    In: Proceedings of the International Plant Sulfur Workshop, Sulfur Metabolism in Plants: Mechanisms and Applications to Food Security and Responses to Climate Change, pp.237-248
    Description: The effect of long-term exposure to elevated pCO2 concentrations on sulfate and nitrate assimilation was studied under field conditions using leaves from Quercus ilex and Quercus pubescens trees growing with ambient or elevated CO2 concentrations in the vicinity of three natural CO2 springs, Bossoleto, Laiatico and Sulfatara, in Tuscany, Italy. The activity of the key enzymes of sulfate assimilation, adenosine 5′-phosphosulfate reductase (APR) and nitrate assimilation, nitrate reductase (NR), were measured together with the levels of acid soluble thiols, and soluble non-proteinogenic nitrogen compounds. Whereas NR activity remained unaffected in Q. ilex or increased Q. pubescence, APR activity decreased in the area of CO2 springs. The latter changes were often accompanied by increased GSH concentrations, apparently synthesized from H2S and SO2 present in the gas mixture emitted from the CO2 springs. Thus, the diminished APR activity in leaves of Q. ilex and Q. pubescence from spring areas can best be explained by the exposure to gaseous sulfur compounds. Although the concentrations of H2S and SO2 in the gas mixture emitted from the vents at the CO2 springs were low at the Bossoleto and Laiatico spring, these sulfur gases pose physiological effects, which may override consequences of elevated pCO2.
    Keywords: Life Sciences ; Plant Sciences ; Plant Physiology ; Plant Biochemistry ; Agriculture ; Plant Ecology ; Climate Change ; Agriculture ; Botany
    ISBN: 9789400744493
    ISBN: 9400744498
    Source: SpringerLink Books
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  • 10
    Language: English
    In: Proceedings of the International Plant Sulfur Workshop, Sulfur Metabolism in Plants: Mechanisms and Applications to Food Security and Responses to Climate Change, pp.255-264
    Description: Drought stress mediated changes in sulfate transport processes, i.e. sulfate uptake and xylem loading of sulfate in the roots, and its dependency on mycorrhization and pCO2 were analyzed in young pedunculate oak (Quercus robur L.) trees. Withdrawal of water supply caused strong negative values of pre-dawn shoot water potential, indicating severe water stress. Elevated pCO2, but not mycorrhization transiently improved the water status of the trees. Sulfate uptake was largely independent from pre-dawn shoot water potential irrespective of mycorrhization and pCO2. In contrast, xylem loading of sulfate decreased with decreasing shoot water potential. Mycorrhization and – to a lesser extent – also elevated pCO2 improved xylem loading under drought stress. As a consequence, also relative xylem loading, i.e. the % amount of the sulfate taken up that was loaded into the xylem, was slightly improved. The positive effect of mycorrhization on xylem loading of sulfate under drought stress is surprising, since plants were inoculated with the ectomycorrhizal fungus Laccaria laccata that is not supposed to enter the vascular bundle of the root. Therefore, signaling by the fungus across the bundle sheath has to be assumed.
    Keywords: Life Sciences ; Plant Sciences ; Plant Physiology ; Plant Biochemistry ; Agriculture ; Plant Ecology ; Climate Change ; Agriculture ; Botany
    ISBN: 9789400744493
    ISBN: 9400744498
    Source: SpringerLink Books
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