Abstract:According to the evolution relationships among Triticum varieties, 21 wheat varieties were chosen as research materials in this experiment to determine the evolutional trends of stomatal and photosynthetic characteristics. The results showed that as ploidy increase, the stomatal length, width, girth and area were found to increase. The stomatal density was found to decrease in A,B,D genomes; however, no differences were found in stomatal indices among ploidies indicating that the stomata became larger but were less in evolution progress. The Diploidy had the highest Pn, which was less in Hetraploidy, and was the least in Hexaploidy. On the contrary, the Hexaploidy had the highest values in Fv/Fm. The Diploidy had the highest chlorophyll content. The net photosynthetic rate had significant correlationship with stomatal conductivity, however, no significant relationship was found among stomatal conductivity and any stomatal characteristics, indicating that the stomatal conductivity is one of the factors limited the photosynthetic rate while the single stamatal characteristics is not the reason that inducing the photosynthetic rate change. The stomatal density showed significant differences among ploidy materials in A,B,D genomes and the trend of genotype was in order of 2n>4n>6n; the stomatal length, width, girth and area showed significant differences among ploidy materials and the trends of genotype was in the order 6n>4n>2n. The results indicate that the low density might induce the low conductivity and low photosynthetic ability in Hexaploidy. Furthermore, the Diploidy had higher values in chlorophyll content of flag leaf area among ploidy materials in A, B, and D genomes, indicating that higher chlorophyll content might be a reason for higher photosynthetic ability in Diploidy wheat species.