ICOM1 Abstract

BRATEK, ZOLTAN1, FERENC LANG1, IBOLYA VOROS2, KLARA BUJTAS2. 1Department of Plant Physiology, Eotvos Lorand University, H-1088 Budapest, POB 330, Hungary. 2Research Institute for Sciences, H-1022 Budapest, Hermann O. œt 15., Hungary. - Effect of heavy metals on mycorrhizated red clover (Trifolium pratense L.): Examination of phothosynthetic properties. The phothosynthetic processes of mycorrhizated (AM) red clover were examined after heavy metal treatment. Cd, Zn or Ni were applied in the same concentrations: 90 kg/ha, 270 kg/ha, 810 kg/ha respectively. The control soil was sterilized by g-radiation. The other control version was made by giving back the bacterial suspension of the original soil. The mycorrhizated plants were taller, their leaf number were higher, and the total dry weight of shoots were larger. The mycorrhiza was not able to prevent the toxic effect of Cd at the highest concentration, but it could protect plants at medium Cd-concentration. The in vivo photosynthetic activity of mycorrhizated plants measured by 14CO2- fixation and fluorescence induction were significantly higher than those of nonmycorrhizated ones in parallel with a similar increase in the chlorophyll content. However, the total chlorophyll content decreased at the highest Cd concentration. There were no significant differences in the chlorophyll a/b ratios. The chlorophyll fluorescence emission and excitation spectra showed a better organized photosynthetic apparatus in mycorrhizated plants.