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Short-term fluctuations of chlorophyll alpha fluorescence versus diurnal variations of solar radiation in the surface water of the Gdansk Basin

100%

Magulski R., Falkowska L., Dunajska D., Pryputniewicz D., Sikorowicz S.

2004

issue 3

57-68

Measurements of chlorophyll alpha fluorescence accompanied by solar radiation measurements were carried out during two spring cruises in the region of the Gdansk Basin. Chlorophyll alpha fluorescence, similarly to that of chlorophyll alpha concentration in the seawater, showed considerable diurnal variability. The measurements provided statistically significant negative correlation coefficients that indicated that chlorophyll a fluorescence is inhibited as solar PAR and UV radiation intensity increases. The approximate range of radiation intensity that corresponded to a clearly marked decline in chlorophyll a fluorescence and chlorophyll alpha concentration was determined. It was revealed that the decline in chlorophyll alpha concentration in the surface water layer resulted from the photodegradation of chlorophyll alpha as well as phytoplankton grazing. In both cases, the resulting observation was an increase of pheophytine a concentration. The vertical migration of phytoplankton was identified as an additional process induced by high radiation levels.

Photosynthetic activity as physiological marker in the evaluation of the quality of shoot cultures and obtained plantlets

75%

Borkowska B.

2003

issue 3

30-38

Chlorophyll alpha fluorescence has become a routine method for obtaining information on various aspects of photosynthesis. The terms and definitions are sometimes used convertibly, which became a source of misunderstanding. In this article, the most accepted viewpoint is presented on chlorophyll fluorescence meaning in monitoring and characterising of photosynthetic events. It was exemplified that strawberry shoot cultures show photosynthetic activity through multiplication subculture. Light and dark phases of photosynthesis function better when glucose is added to the medium in comparison to sucrose-medium. Photosynthetic efficiency of acclimated plantlets is higher than that of cultured shoots, but it is far from full activity of plants growing in natural conditions. The leaves formed during in vitro life slowly decrease, but newly formed leaves acquire the photosynthetic activity at the time of acclimatisation.

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1 Biotechnologia

1 Oceanological and Hydrobiological Studies

1 2004

1 2003

1 Borkowska B.

1 Dunajska D.

1 Falkowska L.

1 Magulski R.

1 Pryputniewicz D.

1 Sikorowicz S.

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Short-term fluctuations of chlorophyll alpha fluorescence versus diurnal variations of solar radiation in the surface water of the Gdansk Basin

Photosynthetic activity as physiological marker in the evaluation of the quality of shoot cultures and obtained plantlets