PECULIARITIES OF THE LEAVES OF THREE WILD SUNFLOWER SPECIES

The study represents the results of the investigation of some peculiarities of the leaves of three wild sunflower species: Helianthus mollis, H. maximilliani, H. nutalli. The leaf width and length, leaf thickness and the thickness of the epidermis, and the peculiarities of the leaf pubescence were studied. The wild sunflower species can be a source of genes of tolerance for many factors, including diseases and drought. We found that the investigated species had statistically significant differences in the leaf blade parameters. The thickness of the leaf was similar. However, the epidermis thickness showed statistically reliable differences between H. maximilliani and H. nutalli. This can be a reason for the different tolerance of this species to drought and high temperatures. Leaf pubescence also showed clear differences between all species. H. mollis has a greater number of hairs on the top and lower epidermis of leaves out of all investigated species. H. nutalli has the lowest number of hairs on its top surface of all these species. However, H. maximilliani has an almost equal number of hairs on both the top and lower epidermis.