The proteins synthesized in different crop plants under different stress conditions (heat, drought, salt, heavy metal and cold) were characterized by ID and 2D SDS-PAGE and protein patterns were detected by silver staining. Under heat stress, in leaf tissues of wheat varieties the synthesis of 16 different proteins at low molecular weight in the range of 15-18 kD and pl:6.0-7.0 were observerd. In rice varieties following 48 hours of 2% NaCl stress two newly synthesized proteins with molecular weights of 25.5 and 27 kD pl:7.0 were detected in root tissues. Cellular fractination analysis revealed the presence of these proteins in soluble matrix. These proteins are not synthesized in response to heat stress, heavy metals, absisic acid and polyethylene glycol treatments. In poppy under cold stress conditions, in leaf tissue the synthesis of a cold specific protein at 37 kD was observed. From these results it was concluded that the proteins syntesized under different stress conditions are species and cultivar specific and might have stress tolerance functions. It was also shown that the photosystem II activity measurements, membrane leakage and TTC mitochondrial viability measurement methods can be used in screening of stress resistant crop plants under laboratory conditions. In tobacco, utilizing the Agrobacterium mediated DNA transfer techtique, the bacterial origin genes coding for neomycine phosphotransferase-II and (3-glucoronidase enzymes were transfered and transgenic plants were obtained. Presence of the transfered genes were also observed in the F[ progeny plants.