Alternaria Brassicae Induced Changes in the Activity of Cell Wall Degrading Enzymes in Leaves of Brassica Juncea

Contents and functioning of photosynthetic pigments and gas exchange of Nicotiana tabacum L. leaves were studied in platlets cultivated in vitro under different CO2 supply. The plantlets were grown for six weeks either in glass vessels tightly closed with aluminium foil (G-plants) or in polycarbonate Magenta GA-7 vessels covered with closures with microporous vents (Mplants). M-plants (better supplied with CO2) had higher contents of chlorophyll (Chl) a. Chl b. and (beta)-carotene, higher photochemical activities of photosystem 2 and whole electron transport chain, and lower contents of xanthophyll cycle pigments. Differences in Chl a fluorescence kinetic parameters between G-plants and M-plants were not statistically significant. M-plants had higher net photosynthetic rate, and lower transpiration rate and stomatal conductance than G-plants.