Effect of heat stress on the synthesis of soluble heat shock proteins ( HSPs) and the regrowth in seminal roots of three cultivated and three wild wheat genotypes was examined. In regrowth experiments, 2-d-old etiolated seedlings were exposed to 23 ( control), 32, 35, 37 and 38 degrees C for 24 h, and 35 and 37 degrees C ( 24 h) followed by 50 degrees C ( 1 h). The lengths of the seminal roots generally decreased significantly at the end of 48 and 72 h recovery growth periods at 35, 37 and 38 degrees C temperature treatments compared with control. Genotypic variability was significant level at all temperature treatments for the seminal root length. Also, genotypic differences for the number of seminal roots were determined among the wheat cultivars and between the wild wheat species and the wheat cultivars at all temperature treatments; but genotypic differences among wild wheat species were only detected at 37 -> 50 degrees C treatment. Acquired thermotolerance for the seminal root length is over 50% at 37 -> 50 degrees C treatment. The genotypic variability of soluble heat shock proteins in seminal root tissues were analyzed by two-dimensional electrophoresis ( 2-DE). Total number of low molecular weight ( LMW) HSPs was more than intermediate( IMW) and high-( HMW) HSPs at high temperature treatments. The most of LMW HSPs which were generally of acidic character ranged between 14.2 - 30.7 kDa. The genotypes had both common ( 43 HSP spots between at least two genotypes and 23 HSP spots between 37 and 37 -> 50 degrees C) and genotype-specific ( 72 HSP spots) LMW HSPs.