In Ukraine, about 15 million hectares of arable land are located in areas of insufficient moisture. It is known that even a slight disturbance in the water balance alters the normal course of metabolic processes and negatively affects plant productivity. The main limiting factor for crop yields in Ukraine is the lack of precipitation. Drought has a negative impact on the optimal course of photosynthesis, transport of assimilants by the plant and hormonal balance. Due to changes in the lipid complex, denaturation and aggregation of proteins, cell membranes are damaged, respiration rate increases with a decrease in its energy efficiency, and the content of phytohormones increases, inhibiting plant division and growth.

Obtaining plant forms with an increased level of resistance to abiotic stresses using the latest biotechnological methods is becoming increasingly important.

Among the biotechnological techniques, cell selection plays an important role. Young tobacco plants (Nicotiana tabaccum L.) were used to obtain biotechnological plants with an increased level of resistance to osmotic stress.

One of the characteristic manifestations of resistance reactions is changes in the level of free L-proline depending on the growing conditions. L-proline-pyrroline-2-carboxylic acid, pro (C₅H₉NO₂) is a heterocyclic compound containing a nitrogen atom in the secondary amine molecule. It exists in the form of two optical isomers, L- and D-forms. The L-form is biologically relevant, and it is also a nonspecific stress protector.