PARENT SESSION
Posters P1D Photosynthesis and global change. Abstracts (699-710)

Effect of water deficit on the thylakoid membranes of two wheat cultivars. Saftar Suleymanov^*,1, Irada Guseynova¹, Jalal Aliyev¹, ¹ Patamdar shosse 40, Baku, Azerbaijan

ABSTRACT- Two wheat (Triticum durum L.) cultivars with different sensitivities to drought were either grown under regular irrigation or subjected to water deficit by withholding water for 15 d. All experiments were carried out in controlled growth cabinet. Changes in one-dimensional gradient (10-25%) gel electrophoresis patterns and spectral characteristics of pigments of thylakoid membranes were analyzed in drought-tolerant (Barakatli-95) and drought-sensitive (Garagylchyg-2) cultivars during dehydration to elucidate the role of different protective mechanisms against stress. It was shown that the content of PS I core (Mr 112 kDa) and apoprotein of P700 (Mr 68 kDa) increases in tolerant cv Barakatli-95 compared to non-stressed seedlings. However the intensity of these polypeptides insignificantly increases in drought-sensitive cv Garagylchyg-2. The plants subjected to water deficit appeared to have a slight increase of - and - subunits of CF1 ATP-synthase complex (57.5 and 55 kDa respectively) in cv Barakatli-95 and their lower content in cv Garagylchyg-2. Steady-state levels of the core antenna of PS II (CP47 and CP43) and light-harvesting Chl a/b- apoproteins remained more or less unchanged. Both cultivars grown under stress conditions showed reduced levels of D-1 protein synthesis of PS II, especially cv Garadylchyg-2, compared to non-stressed plants. At the same time the synthesis of 21.5 kDa polypeptide was about 2-fold higher than that of control cv Barakatli-95. The synthesis of low-molecular polypeptides (16.5 and 14 kDa) also increases in cv Barakatli-95. After exposure to drought Garagilchik-2 had a larger reduction in the photosystem II activity than cv Barakatli-95. Low-temperature fluorescence spectra from stressed plants showed a shift of main 742-nm peak toward to 738 nm in cv Barakatli-95 and 740-nm peak to 738 nm in cv Garagylchyg-2.

KEY WORDS: polypeptides, drought, wheat, florescence