ALBERT — All Library Books, journals and Electronic Records Telegrafenberg

1

Electronic Resource

Water- and pyrophosphate-extractable humic substances fractions as a source of iron for Fe-deficient cucumber plants (1997)

Pinton, R. ; Cesco, S. ; De Nobili, M. ; [et al.]

Springer

Biology and fertility of soils 26 (1997), S. 23-27

add to mindlist on the mindlist

Details

ISSN: 1432-0789

Keywords: Key words Humic substances ; Cucumber ; Iron nutrition ; Iron deficiency ; Root acidification

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The capacity of Fe-deficient cucumber plants to utilise water-extractable and pyrophosphate-extractable humic substances as a source of Fe was investigated. Plants were grown for 13 days in nutrient solution in the presence or absence of Fe and during the last 7 days water-extractable and pyrophosphate-extractable humic substances were added to the solution at a final concentration of 5 μg organic C ml–1. The water-extractable humic fraction did not significantly modify leaf area and dry matter accumulation, leaf total Fe or chlorophyll content of cucumber plants adequately supplied with Fe. In contrast, pyrophosphate-extractable humic substances caused a slight but significant decrease of all the leaf parameters considered, with the exception of the chlorophyll content. Root Fe content of Fe-sufficient plants was decreased by more than 50% in the presence of each humified fraction. Addition of each humic fraction to Fe-deficient plants led to a partial disappearance of leaf chlorosis symptoms with a significant increase in chlorophyll and leaf Fe content. Fe content of roots was also significantly increased in Fe-deficient plants by the addition of humic substances to the nutrient solution. These results show that Fe-deficient cucumber plants can utilise Fe contained in the two fractions of humified organic matter. However, by calculating the amount of total Fe accumulated per plant in the presence of water-extractable or pyrophosphate-extractable humic substances, it could be seen that Fe contained in the water-extractable humic fraction was almost totally used by Fe-deficient cucumber plants, while that present in the pyrophosphate-extractable fraction could only be partially absorbed. The results strongly support a role of humified organic matter in Fe nutrition of plants and are discussed in terms of a possible interaction between soil humic substances and the biochemical mechanisms involved in the plant response to Fe deficiency.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/s003740050337

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

2

Electronic Resource

Germination and Initial Root Growth of Four Legumes as Affected by Landfill Biogas Atmosphere (2000)

Marchiol, L. ; Cesco, S. ; Pinton, R. ; [et al.]

Boston, MA, USA : Blackwell Science Inc

Restoration ecology 8 (2000), S. 0

add to mindlist on the mindlist

Details

ISSN: 1526-100X

Source: Blackwell Publishing Journal Backfiles 1879-2005

Topics: Biology

Notes: The most important problem in the restoration of closed landfills is the production of toxic gases by decomposition of refuse. Such gases affect the root system of plants growing on these sites. The aim of the present study was to assess the effects induced by landfill biogas contamination on germination and initial root growth of Vicia villosa (hairy vetch), Lotus corniculatus (birdsfoot trefoil), Trifolium pratense (red clover), and Trifolium repens (white clover). In laboratory conditions, simulated landfill and control gas were supplied to the seedlings. The composition of the simulated landfill gas used was: 16% O2, 8% CO2, 3% CH4, and 73% N2; a control gas was also tested (21% O2, 0. 035% CO2, and 78% N2). Percentage of germinated seeds was determined after 6 and 12 days from the starting date; at the same time qualitative assays of metabolic root functionality were also performed by using an agar technique in order to visualize changes in rhizosphere pH. At the end of the experiment, the length of the primary and secondary root was measured. Germination after 6 days was affected by the gas treatment; the landfill biogas caused a delay in germination with respect to the control in seeds of V. villosa and L. corniculatus. Root fresh weight and dry weight were significantly decreased by biogas treatment in V. villosa and T. repens. In contrast, root dry weight was higher in gas treated L. corniculatus and T. pratense compared to control seedlings. Total root system was significantly higher in treated T. pratense. The qualitative assay suggests, with the exception of T. pratense, a metabolic adjustment of the treated seedlings.Key words: restoration, landfill biogas, legumes.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1046/j.1526-100x.2000.80013.x

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

3

Electronic Resource

Proton-translocating ATPase activity in plasma membrane vesicles from roots of grapevine seedlings

Pinton, R. ; Varanini, Z. ; Maggioni, A.

Amsterdam : Elsevier

Plant Science 69 (1990), S. 139-145

add to mindlist on the mindlist

Details

ISSN: 0168-9452

Keywords: ATPase ; grapevine roots ; plasma membrane ; proton transport ; vanadate

Source: Elsevier Journal Backfiles on ScienceDirect 1907 - 2002

Topics: Biology

Type of Medium: Electronic Resource

URL: http://linkinghub.elsevier.com/retrieve/pii/0168-9452(90)90112-2

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

4

Electronic Resource

Soil humic substances affect transport properties of tonoplast vesicles isolated from oat roots (1992)

Pinton, R. ; Varanini, Z. ; Vizzotto, G. ; [et al.]

Springer

Plant and soil 142 (1992), S. 203-210

add to mindlist on the mindlist

Details

ISSN: 1573-5036

Keywords: acridine orange ; Avena sativa L. ; humic substances ; oxonol VI ; proton gradient ; tonoplast ATPase ; transmembrane potential

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The effect of a low molecular size (〈5 KDa) humic fraction, essentially fulvic acids, on microsomal and tonoplast ion-stimulated ATPase activity was studied. After 20 min of pre-incubation with microsomal vesicles from oat roots, humic substances at organic C concentration of up to 0.5 μg cm-3 increased KCl-stimulated ATPase activity, while they inhibited enzyme activity at higher concentrations. Cl--stimulated ATPase activity of tightly sealed tonoplast-enriched vesicles was similarly affected by 〈5 KDa humic substances. This behaviour was not observed when gramicidin D was added to the assay medium. Proton transport by vesicles incubated up to 5 min with 〈5 KDa humic molecules was affected in a concentration-dependent manner, strongly resembling that observed for ATP hydrolysis, whereas it was severely reduced when the assay conditions were close to those used for measuring ATP hydrolysis (20 min pre-incubation of vesicles with humic substances). The transmembrane electrical potential was negatively affected, irrespective of the concentration of humic molecules. Furthermore, a 15-min pre-incubation strongly reduced the formation of a potential gradient. The size and concentrations of humic substances employed make an interaction with the vacuolar membrane of root cells plausible. The results show that the main target of humic molecules is the electrical membrane potential and suggest a possible way of interference of these naturally occurring substances with the biochemical mechanisms involved in plant mineral nutrition.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00010966

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

5

Electronic Resource

Properties of potassium uptake by seedling roots of grape cultivars (1990)

Pinton, R. ; Varanini, Z. ; Maggioni, A.

Springer

Plant and soil 123 (1990), S. 175-179

add to mindlist on the mindlist

Details

ISSN: 1573-5036

Keywords: grape nutrition ; H+ efflux ; K+ leakage ; K-ATPase ; potassium uptake

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract Uptake rates of (86Rb)K+ by seedling roots of six cultivars were measured and compared with K+ content of the root, K+ leakage, H+ efflux, and K+-ATPase activity of a partially purified plasmalemma fraction. Different cultivars showed significantly different rates of (86Rb)K+ uptake. The uptake rates of the first (0–5 min) period did not correlate with K+ content of the seedling roots. The rates of uptake in the 10 to 30 min period, supposed to be active, were negatively correlated with K+ content of the root. Roots consistently leaked K+ during the first 5 min. This leakage was positively correlated with the endogenous K+ content of the tissue. H+ efflux was significantly different among the cultivars and correlated with the K+-ATPase activity of a microsomal fraction partially purified on discontinuous (18/34%) sucrose gradient. The relationships among transport parameters are discussed.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00011265

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

6

Electronic Resource

Water-extractable humic substances enhance iron deficiency responses by Fe-deficient cucumber plants (1999)

Pinton, R. ; Cesco, S. ; Santi, S. ; [et al.]

Springer

Plant and soil 210 (1999), S. 145-157

add to mindlist on the mindlist

Details

ISSN: 1573-5036

Keywords: Cucumis sativus ; Fe(III)-chelate reductase ; humic substances ; iron deficiency ; iron nutrition ; root acidification

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The ability of Fe-deficient cucumber plants to use iron complexed to a water-extractable humic substances fraction (WEHS), was investigated. Seven-day-old Fe-deficient plants were transferred to a nutrient solution supplemented daily for 5 days with 0.2 μM Fe as Fe-WEHS (5 μg org. C mL-1), Fe-EDTA, Fe-citrate or FeCl3. These treatments all allowed re-greening of the leaf tissue, and partial recovery of dry matter accumulation, chlorophyll and iron contents. However, the recovery was faster in plants supplied with Fe-WEHS and was already evident 48 h after Fe supply. The addition of 0.2 μM Fe to the nutrient solution caused also a partial recovery of the dry matter and iron accumulation in roots of Fe-deficient cucumber plants, particularly in those supplied with Fe-WEHS. The addition of WEHS alone (5 μg org. C mL-1, 0.04 μM Fe) to the nutrient solution slightly but significantly increased iron and chlorophyll contents in leaves of Fe-deficient plants; in these plants, dry matter accumulation in leaves and roots was comparable or even higher than that measured in plants treated with Fe-citrate or FeCl3. After addition of the different iron sources for 5 days to Fe-deficient roots, morphological modifications (proliferation of lateral roots, increase in the diameter of the sub-apical zones and amplified root-hair formation) and physiological responses (enhanced Fe(III)-chelate reductase and acidification of the nutrient solution) induced by Fe deficiency, were still evident, particularly in plants treated with the humic molecules. The presence of WEHS caused also a further acidification of the nutrient medium by Fe-deficient plants. The Fe-WEHS complex (1 μM Fe) could be reduced by intact cucumber roots, at rates of reduction higher than those measured for Fe-EDTA at equimolar iron concentration. Plasma membrane vesicles, purified by two-phase partition from root microsomes of Fe-deficient plants, were also able to reduce Fe-WEHS. Results show that Fe-deficient cucumber plants can use iron complexed to water soluble humic substances, at least in part via reduction of complexed Fe(III) by the plasma membrane Fe(III)-chelate reductase of root cells. In addition, the stimulating effect of humic substances on H+ release might be of relevance for the overall response of the plants to iron shortage.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1004329513498

Permalink

	Location	Call Number	Expected	Availability

Others were also interested in ...

Paper (German National Licenses)

Fulltext

7

Electronic Resource

Low molecular weight humic substances stimulate H+-ATPase activity of plasma membrane vesicles isolated from oat (Avena sativa L.) roots (1993)

Varanini, Z. ; Pinton, R. ; Biasi, M. G. ; [et al.]

Springer

Plant and soil 153 (1993), S. 61-69

add to mindlist on the mindlist

Details

ISSN: 1573-5036

Keywords: Avena sativa L. ; humic substances ; plasma membrane ; H+-ATPase ; proton gradient

Source: Springer Online Journal Archives 1860-2000

Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition

Notes: Abstract The effect of 〈5 KDa (low molecular weight, LMW) and 〉5 KDa (high molecular weight, HMW) humic fractions on transport activities of isolated plasma membrane vesicles was studied. The K+-stimulated component of the ATP-hydrolyzing activity was considerably increased by LMW humic substances at concentrations ranging from 0.075 mg org CL-1 to 1 mg org CL-1. The stimulation was still evident when the detergent Brij-35 was added in the assay mixture, indicating a direct effect of LMW humic substances on plasma membrane ATPase activity. The LMW humic fraction stimulated ATP-dependent intravesicular H+-accumulation with a pattern similar to that recorded for ATP hydrolysis. LMW humic substances induced also an increase in passive membrane permeability to protons, as revealed by following the dissipation of an artificially imposed pH gradient. Membrane permeability to anions, as measured by the anion-dependent active proton accumulation was affected by LMW humic substances. In the presence of NO3 - these molecules clearly enhanced proton transport, while Cl--dependent activity was almost unaffected, thus suggesting a specific action of LMW humic fraction on transmembrane NO3 - fluxes. On the other hand, HMW humic substances decreased the passive permeability to protons and reduced the anion-dependent intravesicular H+-accumulation. The results suggest that the stimulatory effect of soil humic substances on plant nutrition and growth might be, at least in part, explained on the basis of both direct action of LMW humic molecules on plasma membrane H+-ATPase and specific modification of cell membrane permeability.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1007/BF00010544

Permalink