[Photosynthesis light curves under flash illumination].

Light curve of the multicentral model of photosynthetic unit (PSU) has been obtained. The shape of the curve depends on the efficiency of energy migration between PSU--for the unicentral PSU, and on the number of traps for multicentral PSU. The criteria distinguishing between the two models are proposed.

[Analysis of photosynthesis light curves under continuous illumination].

A mathematical description of the photosynthesis light curve is proposed taking into account the type of photosynthetic unit (PSU) organization (unicentral or multicentral), energy migration between the PSU, and the nonlinear character of the dark process limiting the rate. In the case of unicentral PSU the light curve is described by the expression: I = v (1--yv)/(1--v) where I is light intensity; v is relative rate of photosynthesis (relative to the maximal rate); y is the parameter which determines the shape of the curve. Its value depends on the efficiency of energy migration between PSU and on the ratio of the limiting dark reactions rates.

[Nature of the afterglow of marine algae].

Excitation spectra and light curves were studied in three species of marine algae at monochromatic light excitation of the second-range afterglow. It was shown that light curves were satisfactorily described by an equation similar to the equation of enzyme catalysis with low light intensity of half-saturation (about 0.5 W X m-2).

[Effectiveness of excitation energy migration in the phycobilisomes of red marine macroalgae].

Phycobilisomes (PBS) were isolated from talloms of sea red macroalgae: annual Gloiopeltis furcata from illuminated and shaded shoal and perennial Ahnfeltia tobuchiensis. The spectral changes have shown that R-phycoerythrin, phycocyanin, allophycocyanin, allophycocyanin B were contained in PBS of the algae under study. The efficiency of energy migration to the ultimate acceptor-allophycocyanin B is twice as low in Ahnfeltia tobuchiensis (0.