CHANGES IN SPECTRAL PROPERTIES OF CHLOROPHYLL DURING GREENING OF BARLEY LEAVES

In order to study the formation of photochemical systems in the early phase of greening of barley leaves, we examined the changes in chlorop hyll (Chl) spectral components of the absorption spectrum of greening tissues using a curve analysis method. Peak positions of the fourth-de rivative spectrum were changing during the first 30 min of illuminatio n but became stable thereafter. Results of curve analysis showed that about half of the spectral components of mature leaves were already fo und at 30 min after onset of illumination, and the rest appeared by 4 h. After 30 min the half widths of some spectral components changed sl ightly. The 683 nm form of Chl a of the photosystem II (PSII) core was present after 30 min of illumination and increased up to 2 h, followe d by a decrease. The 691 nm form of Chl a of photosystem I (PSI) appea red at 30 min and increased until 2.5 h. The 699 nm form of Chl a also appeared at 1. 5 h. The 640 nm form of Chl b appeared at 2 h, while t he 649 nm Chl b form was found earlier (1.5 h). Both components were i ncreasing with prolonged time of illumination. Finally, the 704 nm for m of Chl a characteristic of the PSI peripheral antenna appeared at 4 h of greening. Fluorescence of PSI and PSII began to appear at 1 and 2 h, respectively. These spectral changes were discussed in relation to the formation of chlorophyll-protein complexes and the development of photochemical activities.