Intrapopulation heterogeneity of the fluorescence parameters of the marine plankton alga Thalassiosira weissflogii at various nitrogen levels

Abstract

Fluorescence of the marine alga Thalassiosira weissflogii (Grunow) Fryxell et Hasle with open (F o ) and closed (F m ) reaction centers of photosystem 2 (PS 2) and its relative variable fluorescence (F v/F m ) were measured at various levels of inorganic nitrogen. A significant heterogeneity of the population in terms of these parameters was revealed. Some cells within the population were more sensitive to nitrogen deficiency, and their photosynthetic apparatus was disrupted to a greater extent. The cells within a population also differed in terms of their ability to recover after incubation at low nitrogen levels. Enhancement of nitrogen deficiency resulted in an increase in the variability of the F o and F v/F m values of the cells. Fluorescence variability decreased at a less pronounced deficiency. Fluorescence variability should be taken into consideration in the studies concerning responses of algae to changes in nutrient contents.