The present research reports the finding of a small heat shock protein (sHSP) of 5.6 kDa as the protein induced by heat stress. Three different sunflower hybrids derived from the cross between a Cms, HA 89, and three different restorer inbred lines, with resistant, susceptible and normal reaction to drought, were cultivated in two different geographical areas, karaj, Iran and Udine, Italy. The determination of total protein content, structural polypeptide fractions of seed storage protein (SSP) concentration, and the electrophoresis analysis of proteins by means of lab-on-chip capillary electrophoresis had been carried out in order to evaluate the differences between polypeptides of the hybrids SSP. Fatty acid biosynthesis in relationship with the localities of cultivation was followed up, as well. It was determined that protein accumulation in achene occurs at a greater rate during the achene filling phase, in precision 9-25 days after pollination in all examined hybrids. Instead, the expression of sHSP has been found in only one hybrid derived from a restorer tolerant to drought cultivated in the hot-dry climate which expressed a polypeptide band of 5.6 kDa.
