Tobacco plants of Ternopil 14 variety were treated with growth stimulants 1-NAA, GA3 and 6-BAP in the budding phase. Under the influence of growth stimulants, tobacco leaf blades thickened due to the growth of chlorenchyma. The greatest increase in leaf thickness was found after the application of GA3. 1-NAA and GA3 increased the volume of columnar parenchyma cells. The size of the cells of the spongy parenchyma under the action of growth regulators did not change significantly. It was found that 1-NAA reduced the number of epidermal cells and the number of stomata per unit abaxial surface of the leaf, and under the action of 6-BAP, these indicators increased authentically. GA3 increased the number of epidermal cells and decreased the number of stomata. All growth stimulants reduced the area of the stomata. Growth stimulants thickened the collenchyma layer and increased or did not change the size of sclerenchymal fiber cells. The thickness of the shells of sclerenchyma cells increased significantly only with the use of 6-BAP. Under the action of other growth stimulants, this indicator had only a tendency to increase. 1-NAA and 6-BAP increased the thickness of the secondary layer and decreased the primary periderm. Under the action of GA3, the layers of the primary and secondary periderm became thinner. The drugs increased the thickness of the xylem and the diameter of the largest vessels.

Tobacco plants of Ternopil 14 variety were treated with gibberellin inhibitors 2-CEPA, EW-250 and CCC-750. Under the influence of antigibberellins, the leaf blades of tobacco thickened due to the growth of chlorenchyma. The greatest increase in leaf thickness was found after the use of 2-CEPA and EW-25. These same drugs increased the volume of the cells of the columnar parenchyma. The size of the cells of the spongy parenchyma under the action of gibberellin inhibitors was reduced significantly.CCC-750 was found to increase the number of epidermal cells per unit abaxial leaf surface, while 2-CEPA and EW-250 decreased. All growth inhibitors reduced the number of stomata and increased the area of the stomata. All drugs thickened the layer of the primary periderm, and retardants thickened the layer of the collenchyma. EW-250 increased the size of sclerenchymal fiber cells, while other drugs reduced them. All antigibberellins thickened the membranes of sclerenchyma cells. Ethylene producer increased the thickness of the layer of the secondary periderm, and other drugs reduced this figure. EW-250 increased, 2-CEPA decreased, and CCC-750 did not change the thickness of the xylem layer. The diameter of the largest vessels decreased with 2-CEPA and CCC-750 and did not change after treatment with EW-250.