Institute of Botany, Academy of Sciences, 370073 Baku, Patamdar Shosse, 40, Azerbaijan; fax: (994-12) 97-5045; (994-12) 39-3380, E-mail: dj_aliev@baku.ab.az

         It was shown that the apoproteins of core complexes (CC) II and I, a- and b -subunits of CF1 ATP-synthase complexes are present in seedlings grown under intermittent light (IML). The levels of light-harvesting complex (LHC) apoproteins in the 30- to 18- kDa region increase rapidly upon exposure to continuous light (CL). The newly synthesized LHC apoproteins appear to be present predominantly in the monomeric forms that later assembles higher-order oligomeric forms. It was found out that during the first times of greening of wheat seedlings, the polypeptides in the 20.5- to 19 and 17.5- to 15.5 kDa regions (so called "early light-induced proteins" (ELIP)) have been observed which after 6 h are fully disappeared. As greening proceeds, the 727 nm band on low-temperature fluorescence spectra (77 K) gradually shifts to longer wavelengths of 740 nm which clearly demonstrates the light-driven biogenesis of LHC I and its assembly with CC I.     
        KEY WORDS: greening, fluorescence, early light-induced proteins, plastids, light-harvesting complex, wheat

       INTRODUCTION
              Photosystem (PS) I and II of higher plant thylakoid membranes include core complex (CC) containing the photochemical reaction center and chlorophyll (Chl) a/b-containing light-harvesting complex (LHC), the function of which is to absorb photons and to transfer excitation energy to the reaction center [1].
        More favourable objects for studying of plastid biogenesis are developing chloroplasts, which enable to follow separate stages of following structural change [2]. Upon investigation of etioplast transition to chloroplast as a result of illumination of the plants which were grown in full darkness it is possible to follow the synthesis of separate components of photosynthetic membrane (proteins, lipids, pigments and i.e.) in detail, their assembly and development. A number of occurrences in developing etioplasts may be controlled by light intensity and quality and by duration of light exposition, therefore etioplasts are unchangeable model for studying of photosynthetic apparatus biogenesis of higher plants [3].
        Growth of etiolated plants in intermittent light arrests plastid development at the stage of the protochloroplast which synthesizes Chl a and carotenoids selectively and are essentially devoid of Chl b [4]. These protochloroplasts have a complete electron transfer chain and functional CC I and CC II components. In spite of the presence of substantial amounts of Lhc (cab) mRNAs, there is little accumulation of LHC apoproteins, particularly of the LHC II apoproteins, in IML-grown leaves [5]. In plants exposed to intermittent light, or in plants transferred to darkness after brief preexposure to continuous light (i.e. under conditions where Chl synthesis is stopped), preaccumulated LHC II apoproteins are degraded because of rapid turnover of their apoproteins in the absence of stabilization by the photosynthetic pigments; while the reaction center components continue to be synthesized [6]. Thus when Chl accumulation is low, LHC apoproteins can not form Chl-protein complexes [7-10].
        The purpose of the present paper is to examine the assembly of chlorophyll-protein complexes of chloroplast thylakoid membrane in greening wheat seedlings. In particularly we enabled to study cooperation between the synthesis and accumulation of chlorophyll-protein complexes proteins and their native spectral properties for more precise determination in vivo status of the assembly and formation of these complexes in developing plastid.

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