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  • 1995-1999  (5)
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  • 1
    Electronic Resource
    Electronic Resource
    Uptake and transport of zinc in the hyperaccumulator Thlaspi caerulescens and the non-hyperaccumulator Thlaspi ochroleucum (1997)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 20 (1997), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Growth and zinc uptake of the hyperaccumulator species Thlaspi caerulescens J. & C. Presl and the non-hyperaccumulator species Thlaspi ochroleucum Boiss. & Heldr. were compared in solution culture experiments. T. caerulescens was able to tolerate 500 mmol m−3 (32.5 g m−3) Zn in solution without growth reduction, and up to 1000 mmol m−3 (65 g m−3) Zn without showing visible toxic symptoms but with a 25% decrease in dry matter (DM) yield. Up to 28 g kg−1 of Zn in shoot DM was obtained in healthy plants of T. caerulescens. In contrast, T. ochroleucum suffered severe phytotoxicity at 500 mmol m−3 Zn. Marked differences were shown in Zn uptake, distribution and redistribution between the two species. T. caerulescens had much higher concentrations of Zn in the shoots, whereas T. ochroleucum accumulated higher concentrations of Zn in the roots. When an external supply of 500 mmol m−3 Zn was withheld, 89% of the Zn accumulated previously in the roots of T. caerulescens was transported to the shoots over a 33 d period, whereas in T. ochroleucum only 32% was transported. T. caerulescens was shown to have a greater internal requirement for Zn than other plants. Increasing the supply of Zn from 1 to 10 mmol m−3 gave a 19% increase in the total DM of this species. liven the shoots from the 1 mmol m−3 Zn treatment which showed Zn deficiency contained 10 times greater Zn concentrations than the widely reported critical value for Zn deficiency to occur in many other plant species. The results obtained suggest that strongly expressed constitutive sequestration mechanisms exist in the hyperaccumulator T. caerulescens, which detoxify the large amount of Zn present in shoot tissues and decrease its physiological availability in the cytosol. Both T. caerulescens and T. ochroleucum had constitutively high concentrations of malate in shoots, which were little affected by different Zn treatments. Although malate may play a role in Zn chelation because of the high concentrations present, it cannot explain the species specificity of Zn tolerance and hyperaccumulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.1997.d01-134.x
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    Solubility of zinc and interactions between zinc and phosphorus in the hyperaccumulator Thlaspi caerulescens (1998)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 21 (1998), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: The relationship between Zn and P in the Zn hyperaccumulator Thlaspi caerulescens J. & C. Presl was investigated using hydroponic culture. Total concentrations of Zn in the shoots increased from 0·2 to 27 g kg–1 dry mass when solution Zn increased from 1 to 1000 mmol m–3. Water-soluble Zn accounted for 〉 80% of the total Zn in the shoots containing 〉 5 g Zn kg–1 dry mass. Total P was maintained at about 3 g kg–1 dry mass in the shoots containing 〈 20 g Zn kg–1 dry mass, but significantly decreased with higher Zn concentrations. Linear regression between insoluble P and insoluble Zn in the shoots produced a small slope, suggesting that co-precipitation of Zn and P was not an important detoxification mechanism in the shoots. In contrast, there was a strong correlation between insoluble P and insoluble Zn in the roots, with a linear slope of 0·3 — close to the P:Zn ratio in Zn3(PO4)2. Foliar sprays of phosphate did not affect shoot dry mass significantly, but decreased root length and root dry mass significantly at Zn concentrations in solution from 10 to 3000 mmol m–3. Foliar P was translocated to roots to enhance co-precipitation of Zn and P, although this did not enhance Zn tolerance. The results suggest that T.caerulescens possesses mechanisms which allow it to accumulate and sequester huge amounts of Zn in the shoots without causing P deficiency.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-3040.1998.00270.x
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Changes in trace metal species and other components of the rhizosphere during growth of radish (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Plant, cell & environment 18 (1995), S. 0 
    Details
    ISSN: 1365-3040
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Changes in the properties of soil solution in the rhizosphere of developing radish plants were investigated. Variations in these properties were expected to affect the distribution and speciation of metals in the soil and soil solution. Applications of essential nutrients were linked to plant transpiration rates and prevented excess addition of nutrient ions, so that subtle changes in soil solution composition would not be obscured. Soil solution pH, the concentration of dissolved organic carbon (DOC) and the concentrations of major and trace elements in solution were found to vary over time. Strict control of fertilizer additions led to the maintenance of a relatively low ionic strength in the soil solution, and under such conditions trace metal solubility appeared to be highy influenced by the concentration of DOC. A chemical speciation analysis was performed which showed that, while dissolved Cd and Zn were largely uncomplexed in unplanted soil, Cd and Zn in the rhizosphere existed mainly as complexed forms. It is hypothesized that this is partly a result of Ca-metal-ligand equilibrium in solution, with higher Ca concentrations in unplanted soil leading to more of the Cd and Zn in solution existing in the uncomplexed state. Changes in the concentrations of uncomplexed Cd and Zn with time gave the best correlations with changes in plant uptake of these metals over time, supporting the hypothesis that plants mainly absorb the free metal ion from soil solution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1365-3040.1995.tb00577.x
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    Paper (German National Licenses)
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  • 4
    Electronic Resource
    Electronic Resource
    Effects of sulphur nutrition on growth and nitrogen fixation of pea (Pisum sativum L.) (1999)
    Springer
    Plant and soil 212 (1999), S. 207-217 
    Details
    ISSN: 1573-5036
    Keywords: legume ; nitrogen ; N2-fixation ; pea ; sulphur
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract A S-deficient soil was used in pot experiments to investigate the effects of S addition on growth and N2-fixation in pea (Pisum sativum L.). Addition of 100 mg S pot−1 increased seed yield by more than 2-fold. Numbers of pods formed were the most sensitive yield component affected by S deficiency. Sulphur addition also increased the concentration of N in leaves and stems, and the total content of N in the shoots. The amounts of N fixed by pea were determined at four growth stages from stem elongation to maturity, using the 15N dilution technique. Sulphur addition doubled the amount of N fixed at all growth stages. In contrast, leaf chlorophyll content and shoot dry weight were increased significantly by S addition only after the flowering and pod fill stage, respectively. Pea roots were found to have high concentrations of S, reaching approximately 10 mg g−1 dry weight and being 2.6–4.4 times the S concentration in the shoots under S-sufficient conditions. These results suggest that roots/nodules of pea have a high demand for S, and that N2-fixation is very sensitive to S deficiency. The effects of S deficiency on pea growth were likely to be caused by the shortage of N, due to decreased N2-fixation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1023/A:1004618303445
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    Paper (German National Licenses)
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  • 5
    Electronic Resource
    Electronic Resource
    Responses of two wheat varieties to sulphur addition and diagnosis of sulphur deficiency (1996)
    Springer
    Plant and soil 181 (1996), S. 317-327 
    Details
    ISSN: 1573-5036
    Keywords: diagnosis ; glutathione ; N:S ratio ; sulphur ; sulphate ; wheat variety
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Sulphur deficiency has become increasingly widespread in wheat in the U.K. Growth, nutrient content and biochemical responses to S and N supply of a breadmaking wheat variety (Hereward) and a non-breadmaking variety (Riband) were investigated in a pot experiment. Shoot dry matter (DM) at stem extension (Zadok's GS 37) and at maturity was increased markedly by S. Grain production of the Riband variety was more susceptible to the imbalance of N to S than the Hereward variety. At GS 37, the concentrations of total S and sulphate-S of shoots, chlorophyll meter readings and the concentrations of glutathione of the uppermost fully expanded leaves were increased significantly by increasing S supply, whereas the concentrations of nitrate and amides were decreased by S. The greatest relative changes in response to S supply were those of the glutathione and asparagine concentrations. Riband also showed greater response to S than Hereward. Critical values of various diagnostic indices at GS 37 were derived from the relationships between DM yield and different indices. The two varieties showed similar diagnostic curves except that for the ratio of total N to total S (N:S) in shoots. Either total S or sulphate-S can be used alone as a good indicator of deficiency, and with values of 1500 and 190 mg kg-1 DM in shoots for the two indices respectively. There was also a well defined relationship between DM yield and the glutathione concentration, with a critical value of 240 nmol g-1 FW. There were no advantages of using % of total S as sulphate-S. Shoot N:S ratio was found to be less accurate in predicting S deficiency than total S or sulphate-S. For prognostic purposes, a much higher S status at GS 37 was required to ensure no losses of DM yield due to S deficiency at maturity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00012066
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    Paper (German National Licenses)
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