AMBIENTUM BIOETHICA BIOLOGIA CHEMIA DIGITALIA DRAMATICA EDUCATIO ARTIS GYMNAST. ENGINEERING EPHEMERIDES EUROPAEA GEOGRAPHIA GEOLOGIA HISTORIA HISTORIA ARTIUM INFORMATICA IURISPRUDENTIA MATHEMATICA MUSICA NEGOTIA OECONOMICA PHILOLOGIA PHILOSOPHIA PHYSICA POLITICA PSYCHOLOGIA-PAEDAGOGIA SOCIOLOGIA THEOLOGIA CATHOLICA THEOLOGIA CATHOLICA LATIN THEOLOGIA GR.-CATH. VARAD THEOLOGIA ORTHODOXA THEOLOGIA REF. TRANSYLVAN
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STUDIA BIOLOGIA - Issue no. 2 / 2004 | |||||||
Article: |
EFECTELE INTENSITĂŢII LUMINII ŞI A DURATEI DE EXPUNERE ASUPRA MANIFESTĂRII FOTOINHIBIŢIEI LA ALGA VERDE CHLORELLA FUSCA SHIHIRA ET KRAUSS. Authors: VICTOR BERCEA, ANA NICOARĂ. |
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Abstract: The Effects of Light Intensity and of the Duration of Exposure on the Manifestation of Photoinhibition in Chlorella fusca Shihira et Krauss Green Alga. The aim of the paper is to point out the existence of the xanthophyll cycle in Chlorella fusca, as well as the photoinhibition effects induced by high light on the photosynthetic apparatus. The light intensities of 1000, 1500, 2000, 2500 and 3000 μmol.m-2.s-1, for a duration of 30, 60, 90 and 120 min were used. The content of chlorophylls and carotenoids increases in the first 30 min, in positive relationship with protein levels. The redox state of the two photosystems was assessed by the spectral differences at 320 nm and 700 nm. The deepoxidation reactions of violaxanthin are rapid, occurring within 30 min, and it is proportional to light intensity. The epoxidation of zeaxanthin is slower, and it is also correlated with the synthesis of proteins. Higher light intensities produce various damage. The kinetics of deepoxidation and epoxidation were highlighted by indexes DEPS and EPS, respectively. | |||||||