Cytogenetic and Morphophysiological Effects of Exogenous Triacontanol against Drought in Barley

Drought stress is one of the leading abiotic stresses that have a devastating impact on sustainable agricultural policy as a result of the decrease in crop yield. For this reason, hormones or growth regulators can be used to grow plants that can adapt to morphological and physiological changes caused by stress. Triacontanol (TRIA) is a hormone that takes part in abiotic stress tolerance mechanisms and performs this task by ensuring the continuity of growth, productivity, development and vital metabolic processes. In this study, the morphophysiological and cytogenetic effects of exogenous TRIA application in barley (Hordeum vulgare cv. Avcı) under drought stress were investigated. The results showed that drought stress negatively affected barley both morphophysiologically and cytogenetically. Application of exogenous TRIA had an increasing effect on germination percentage, radicle number, coleoptile length and percentage under drought stress. Moreover, in the same environment, with the effect of TRIA, there was an increase in the mitotic index (44%) and a decrease in chromosomal abnormalities (46%). The conclusion drawn from this study is that the application of 10 µM TRIA application causes physiological and cytogenetic improvements in barley under drought stress, resulting in the plant's stress tolerance.