Chlorophyll fluorescence and polypeptide composition of thylakoids under NaCl and polyethylenglycol action on wheat seedlings

摘要

The comparative investigation of wheat seedling (Triticum aestivum L.) leaves and thylakoid photosynthetic membranes state with different time (from 1 to 24 h) of water deficit caused by NaCl and polyethylenglycol (PEG), creating osmotic pressure equal to 14.5 centre dot 10~5 Pa was carried out. The results of measurement delayed light emission (DLE), fluorescence spectra and polypeptide analysis show the membrane different sensitivity to stress action. The decrease of intensity of DLE components, which reflect the state of the PSII reaction center, the electrochemical proton gradient and the rate of electron transport is observed during first 30 min. of stress caused by NaCl while PEG action was observed after 120 min. Cl~- ions action was revealed rapidly under investigations of chlorophyll fluorescence. Polypeptide spectra of thylakoids changed only under effect of NaCl solution action. The new electrophoretic zones of 49 and 38 kDa proteins appeared under chlorine salinity and 38 kDa in the case of PEG with disappearance of 25 and 16 kDa proteins. The changes occurring in the membranes were the result of Cl~- ions toxic effect in the first turn and not a water deficit caused by PEG.