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Titolo:
COLD-HARDENING RESULTS IN INCREASED ACTIVITY OF ENZYMES INVOLVED IN CARBON METABOLISM IN LEAVES OF WINTER RYE (SECALE-CEREALE L)
Autore:
HURRY VM; KEERBERG O; PARNIK T; GARDESTROM P; OQUIST G;
Indirizzi:
AUSTRALIAN NATL UNIV,RES SCH BIOL SCI,COOPERAT RES CTR PLANT SCI,BOX 475 CANBERRA ACT 2601 AUSTRALIA ESTONIAN ACAD SCI,INST EXPTL BIOL KHARKU ESTONIA UMEA UNIV,DEPT PLANT PHYSIOL S-90187 UMEA SWEDEN
Titolo Testata:
Planta
fascicolo: 4, volume: 195, anno: 1995,
pagine: 554 - 562
SICI:
0032-0935(1995)195:4<554:CRIIAO>2.0.ZU;2-T
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOSYNTHETIC SUCROSE SYNTHESIS; LOW-TEMPERATURE; FRUCTOSE 2,6-BISPHOSPHATE; PHOSPHATE SYNTHASE; FREEZING TOLERANCE; LIGHT ACTIVATION; NERIUM-OLEANDER; SPINACH LEAVES; BARLEY LEAVES; WHEAT;
Keywords:
FROST HARDENING; LOW TEMPERATURE; PHOTOSYNTHESIS; RIBULOSE-1,5-BISPHOSPHATE CARBOXYLASE OXYGENASE; SECALE; SUCROSE-PHOSPHATE SYNTHASE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
47
Recensione:
Indirizzi per estratti:
Citazione:
V.M. Hurry et al., "COLD-HARDENING RESULTS IN INCREASED ACTIVITY OF ENZYMES INVOLVED IN CARBON METABOLISM IN LEAVES OF WINTER RYE (SECALE-CEREALE L)", Planta, 195(4), 1995, pp. 554-562

Abstract

Light- and CO2-saturated photosynthesis of nonhardened rye (Secale cereale L. cv. Musketeer) was reduced from 18.10 to 7.17 mu mol O-2.m(-2).s(-1) when leaves were transferred from 20 to 5 degrees C for 30 min. Following cold-hardening at 5 degrees C for ten weeks, photosynthesis recovered to 15.05 mu mol O-2.m(-2).s(-1), comparable to the non-hardened rate at 20 degrees C. Recovery of photosynthesis was associated with increases in the total activity and activation of enzymes of the photosynthetic carbon-reduction cycle and of sucrose synthesis. The total hexose-phosphate pool increase by 30% and 120% for nonhardened andcold-hardened leaves respectively when measured at 5 degrees C. The large increase in esterified phosphate in cold-hardened leaves occurredwithout a limitation in inorganic phosphate supply. In contrast, the much smaller increase in esterified phosphate in nonhardened leaves was associated with an inhibition of ribulose-1,5-bisphosphate carboxylase/oxygenase and sucrose-phosphate synthase activation. It is suggested that the large increases in hexose phosphates in cold-hardened leaves compensates for the higher substrate threshold concentrations neededfor enzyme activation at low temperatures. High substrate concentrations could also compensate for the kinetic limitations imposed by product inhibition from the accumulation of sucrose at 5 degrees C. Nonhardened leaves appear to be unable to compensate in this fashion due to an inadequate supply of inorganic phosphate.

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Documento generato il 04/12/20 alle ore 19:14:17