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Titolo:
SHORT-TERM EFFECTS OF BORON, GERMANIUM AND HIGH LIGHT-INTENSITY ON MEMBRANE-PERMEABILITY IN BORON DEFICIENT LEAVES OF SUNFLOWER
Autore:
CAKMAK I; KURZ H; MARSCHNER H;
Indirizzi:
CUKUROVA UNIV,FAC AGR,DEPT SOIL SCI & PLANT NUTR ANKARA 01330 TURKEY UNIV HOHENHEIM,INST PFLANZENERNAHRUNG 330 D-70593 STUTTGART GERMANY
Titolo Testata:
Physiologia Plantarum
fascicolo: 1, volume: 95, anno: 1995,
pagine: 11 - 18
SICI:
0031-9317(1995)95:1<11:SEOBGA>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
ROOTS; PLANTS; CELL; POLYPHENOLOXIDASE; OXIDATION; TRANSPORT; K+;
Keywords:
BORON DEFICIENCY; GERMANIUM; HELIANTHUS ANNUUS; HIGH LIGHT INTENSITY; MEMBRANE PERMEABILITY; POTASSIUM EFFLUX; SUNFLOWER;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
33
Recensione:
Indirizzi per estratti:
Citazione:
I. Cakmak et al., "SHORT-TERM EFFECTS OF BORON, GERMANIUM AND HIGH LIGHT-INTENSITY ON MEMBRANE-PERMEABILITY IN BORON DEFICIENT LEAVES OF SUNFLOWER", Physiologia Plantarum, 95(1), 1995, pp. 11-18

Abstract

The effects of varied boron (B) supply (0.01-50 mu M) and light intensity (100-580 pmol m(-2) s(-1)) on plant growth, leaf symptoms and membrane permeability of leaves were studied in sunflower plants over a 10-day-period of growth in nutrient solution. Membrane permeability wasmeasured by incubating isolated young leaves in aerated distilled water. Additional experiments showed the effect of short-term supply (20 min to 2 h) of B and germanium (Ge) on membrane permeability of B-deficient leaves incubated in distilled water. Low supply of B decreased shoot and root growth and caused brown-purple pigmentation of young leaves, particularly under high light intensities. Leakage of K+ from leaves increased with severity of B deficiency whereas, in B-sufficient leaves, leakage of solutes was low. Also leakage of phenolics, amino acids and sucrose was enhanced by B deficiency. Compared to B-sufficientleaves, the leakage from B-deficient leaves was 35-fold higher for K+, 45-fold higher for sucrose and 7-fold higher for phenolics and aminoacids. Increases in solute leakage were marked in leaf areas with brown-purple pigmentation and particularly pronounced by increasing lightintensity or by exposure of leaves to continuous light. In severely B-deficient leaves grown under high light intensity, treatment with B and Ge up to 1 000 mu M for 20 min resulted in an immediate decrease inK+ efflux to about the same levels as in B-sufficient leaves. Similarrapid decreases in K+ efflux were also found in B-deficient leaves when exposed to darkness for 16 h or 30 h before the leakage measurement. The results demonstrate a particular role for B in maintaining the integrity of plasma membranes. Boron presumably stabilizes the structure of the plasma membrane by complexing membrane constituents. It also has a protective effect on membrane constituents by complexing phenolics, so that oxidation of phenolics to highly toxic quinones and oxygenfree radicals is prevented or limited. In these functions, boron seems to be to a large extent replaceable by germanium.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 20/09/20 alle ore 04:27:25