UV-B INDUCED ALTERATIONS IN COMPOSITION OF THYLAKOID MEMBRANE AND AMINO-ACIDS IN LEAVES OF RHIZOPHORA-APICULATA BLUME

Seedlings of Rhizophora apiculata were exposed to UV-B radiation at fo ur doses equivalent to 10, 20, 30, and 40 % ozone depletion. The seedl ings irradiated with high doses of UV-B had characteristic decline in contents of specific proteins with molecular masses of 33, 23, and 17 kDa. On the contrary, proteins of 55, 33, 25, 23, and 17 kDa were accu mulated in the seedlings exposed to low doses of UV-B. The UV-B, in ge neral, enhanced formation of saturated fatty acids and reduced unsatur ated fatty acids, to a maximum extent of 88 and 26 %, respectively. Th e low dose of UV-B increased content of oleic acid by 9 %, and the hig h dose reduced it by 34 %. The high dose of UV-B enhanced the lipid pe roxidation by 48 %, whereas the low dose of UV-B did not show any sign ificant effect. The contents of amino acids such as aspartate, glutama te, asparagine, serine, glutamine, threonine, and histidine were incre ased in low UV-B doses by 53, 86, 142, 72, 3, 119, and 32 %, respectiv ely; while in high doses they were reduced significantly.