%0 Journal Article
%T Effect of cobalt on growth, pigments and the photosynthetic electron transport in Monoraphidium minutum and Nitzchia perminuta
%A El-Sheekh
%A M.M.
%A El-Naggar
%A A.H.
%A Osman
%A M.E.H.
%A El-Mazaly
%A E.
%J Brazilian Journal of Plant Physiology
%D 2003
%I Scientific Electronic Library Online
%R 10.1590/S1677-04202003000300005
%X the unicellular green alga monoraphidium minutum and the diatom nitzschia perminuta were cultured under different concentrations of co2+. growth and pigment content were slightly increased at low concentrations and inhibited by high co2+ concentrations. the results concerning the effect of different concentrations of co2+ on photosynthetic o2 evolution showed a reduction in the amount of o2 evolved by each alga in response to increasing co2+ concentrations. however, an increase in o2 evolution for both m. minutum and n. perminuta was observed at relatively low co2+ concentrations. photosynthetic electron transport in m. minutum was more sensitive to co2+ toxicity than in n. perminuta. on the other hand, the effect of the heavy metal on respiration showed that higher co2+ concentrations were inhibitory to o2 uptake by the two algal species. low co2+ concentrations stimulated o2 uptake by m. minutum throughout the experimental period. however, in n. perminuta, different concentrations of co2+ led to a reduction of o2 uptake. to localize the action site of co2+ in the photosynthetic electron transport chain, the fluorescence induction technique was carried out. according to the results obtained, the inhibitory action of co2+ is located on the acceptor side of psii for both m. minutum and n. perminuta.
%K cobalt
%K diatoms
%K green algae
%K pigments
%K photosynthesis.
%U http://www.scielo.br/scielo.php?script=sci_abstract&pid=S1677-04202003000300005&lng=en&nrm=iso&tlng=en