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International Journal on Algae

ISSN for PRINT: 1521-9429

Institutional price:	$905.00
Issues per year:	4

Best Paper Award Selection - Editorial Board Site

2004, Volume6

104 pages

DOI: 10.1615/InterJAlgae.v6.i3

Issue price - $216.00

Effect of light of different intensity on chlorophyll fluorescence of Ulva pertusa Kjellman (Chlorophyta)

Yu. I. Posudin
National Agricultural University, Chair of Biophysics, 15, Geroyev Oborony St., Kiev, 03041 Ukraine

Mitsunobu Kamiya
Kobe University Research Center for Inland Seas, Iwaya 2746, Awajicho, Tsunagun, Hyogo, 656-2401 Japan

Akio Murakami
Kobe University Research Center for Inland Seas, Iwaya 2746, Awajicho, Tsunagun, Hyogo, 656-2401 Japan

Hiroshi Kawai
Kobe University Research Center for Inland Seas, Iwaya 2746, Awajicho, Tsunagun, Hyogo, 656-2401 Japan

ABSTRACT

The effects of high-intensity optical radiation on chlorophyll fluorescence of marine alga Ulva pertusa Kjellman (Chlorophyta) were investigated. The method of pulse amplitude modulated (PAM) chlorophyll fluorescence was used for studying the photoinhibition of photosynthesis of alga. Treatment of the dark-adapted samples with low-intensity (30 μmol·m⁻²·s⁻¹) white light produced no significant difference between values of optimal quantum yield Y_opt of illuminated samples and samples kept in the dark. Treatment of the samples with high (1800 μmol·m⁻²·s⁻¹) intensity of white light provoked photoinhibition: the value of effective quantum yield Y_eff decreased up to 33 % in 2 hours in comparison with the samples kept in the dark. Damage to the photosynthetic apparatus of alga by high irradiances is reversible: after the end of the photoinhibitory treatment the values of fluorescence parameters reached the initial level in the next 2 hours. The possible mechanisms of quenching of chlorophyll fluorescence are discussed. Fluorescence parameters such as effective and optimal quantum yields, photosynthetic efficiency, and capacity make it possible to estimate the effects of high-intensity irradiation on photosynthetic organisms.