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Titolo:
SEASONAL-CHANGES IN PHOTOSYSTEM-II ORGANIZATION AND PIGMENT COMPOSITION IN PINUS-SYLVESTRIS
Autore:
OTTANDER C; CAMPBELL D; OQUIST G;
Indirizzi:
UMEA UNIV,DEPT PLANT PHYSIOL S-90187 UMEA SWEDEN
Titolo Testata:
Planta
fascicolo: 1, volume: 197, anno: 1995,
pagine: 176 - 183
SICI:
0032-0935(1995)197:1<176:SIPOAP>2.0.ZU;2-9
Fonte:
ISI
Lingua:
ENG
Soggetto:
PHOTOSYNTHETIC ELECTRON-TRANSPORT; LIGHT-INDUCED PROTEINS; SCOTS PINE; CHLOROPHYLL FLUORESCENCE; ENERGY-DISTRIBUTION; BINDING-PROTEIN; HIGHER-PLANTS; ZEAXANTHIN; PHOTOINHIBITION; TEMPERATURE;
Keywords:
CAROTENOID; CHLOROPHYLL-BINDING POLYPEPTIDE; LOW TEMPERATURE STRESS; PHOTOINHIBITION; PHOTOPROTECTION; PINUS;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
48
Recensione:
Indirizzi per estratti:
Citazione:
C. Ottander et al., "SEASONAL-CHANGES IN PHOTOSYSTEM-II ORGANIZATION AND PIGMENT COMPOSITION IN PINUS-SYLVESTRIS", Planta, 197(1), 1995, pp. 176-183

Abstract

Conifers of the boreal zone encounter considerable combined stress oflow temperature and high light during winter, when photosynthetic consumption of excitation energy is blocked. In the evergreen Pinus sylvestris L. these stresses coincided with major seasonal changes in photosystem II (PSII) organisation and pigment composition. The earliest changes occurred in September, before any freezing stress, with initial losses of chlorophyll, the D1-protein of the PSTI reaction centre and of PSII light-harvesting-complex (LHC Il) proteins. In October there was a transient increase in F-o, resulting from detachment of the light-harvesting antennae as reaction centres lost D1. The D1-protein content eventually decreased to 90%, reaching a minimum by December, but PSII photochemical efficiency [variable fluorescence (F-v)/maximum fluorescence (F-m)] did not reach the winter minimum until mid-February. The carotenoid composition varied seasonally with a twofold increase in lutein and the carotenoids of the xanthophyll cycle during winter, while the epoxidation state of the xanthophylls decreased from 0.9 to 0.1from October to January. The loss of chlorophyll was complete by October and during winter much of the remaining chlorophyll was reorganised in aggregates of specific polypeptide composition, which apparently efficiently quench excitation energy through non-radiative dissipation. The timing of the autumn and winter changes indicated that xanthophyll de-epoxidation correlates with winter quenching of chlorophyll fluorescence while the drop in photochemical efficiency relates more to loss of D1-protein. In April and May recovery of the photochemistry of PSII, protein synthesis, pigment rearrangements and zeaxanthin epoxidation occurred concomitantly. Indoor recovery of photosynthesis in winter-stressed branches under favourable conditions was completed within 3d, with rapid increases in F-o, the epoxidation state of the xanthophylls and in light-harvesting polypeptides, followed by recovery of D1-protein content and F-v/F-m, all without net increase in chlorophyll. The fall and winter reorganisation allow Pinus sylvestris is to maintain a large stock of chlorophyll in a quenched, photoprotected state, allowing rapid recovery of photosynthesis in spring.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/12/20 alle ore 18:33:47