Abstract This study presents for the first time data on the composition of microelements and polyprenols in the extract of cotton leaves (Gossypium hirsutum L.) variety T-104 and the effect of presowing treatment with the extract on the responses of cultivated plants in the initial period of development. It has been established that, according to the quantitative composition of polyprenol homologues, the extract of the leaves of the cotton line T-104 differs from the previously developed drug Uchkun. In this extract, undecaprenol dominates with a content of 72.5%, and also decaprenol was detected in an amount of 8.8% and dodecaprenol 18.7%. It was revealed that the content of trace elements, such as manganese and copper in the leaves of cotton line T104 is 4-5 times higher than that of the 108-F variety. As a result of treatment with an extract of some cultural plants (wheat seeds, cucumber and radishes), it was observed that the growth of stems is more activated. It was found that the extract, as well as the drug uchkun, contributes to an increase in the content of cytokinin in wheat seedlings. The extract has been shown to have a high stress-protective activity. It stimulates plant growth and increases wet and dry mass when plants are grown under saline conditions.