Time of Appearance of Photosystems I and II in Chloroplasts of Greening Jack Bean Leaves

Abstract

The time of appearance of photochemical activities together with the chlorophyll-protein complexes associated with photosystems I and II was followed in greening primary leaves of jack bean (Canavalia ensiformis (L.) DC.). When greening of the etiolated leaves occurred under high relative humidity conditions, no lag phase in chlorophyll-accumulation was observed. These environmental conditions also promoted rapid and uniform development of the chloroplast lamellar system. Chlorophyll-protein complexes of the lamellae were separated by means of sodium dodecylsulphate-polyacrylamide gel electrophoresis and by hydroxylapatite chromatography. The photosystem II complex, containing chlorophyll a/b-protein, was detected after 2 h of greening. Its appearance was correlated with a sharp decrease in the chlorophyll a/b ratio and with the onset of oxygen evolution. Subsequently, the photosystem I complex, containing a chlorophyll a-protein, was detected—after 6 h of illumination. Its appearance coincided with the detection of light-induced bleaching of P700 and the beginning of a rising chlorophyll a/b ratio that plateaued some time later.