Effect of seed priming with zeatin on Secale cereale L. growth and cytokinins homeostasis under hyperthermia

ABSTRACT The rise in temperature during autumn is one of the most serious negative factors for winter rye (Secale cereale L.), which leads to wilting, plant damage by fungal diseases and yield losses. The aim of the current study was to elucidate the possibility of overcoming the consequences of heat stress through seed priming with zeatin solution. Rye seeds (cv. Boguslavka) were soaked in zeatin (Z) solution (10−6 M) or water for 3 h. Seedlings were grown at a temperature of +16° C in sand culture. The 7-day-old plants were exposed to heat stress (+35° C) for 2 h (alarm phase of response) or for 6 h for 2 days (acclimation phase of response). Then plants recovered for 5 d under initial conditions. Endogenous cytokinins content was analyzed by HPLC-MS method. Hyperthermia had a differential effect on the content of individual cytokinins and their localization in the shoots and roots of rye plants. Pre-sowing treatment of rye seeds with zeatin solution resulted in significant changes in cytokinin status in shoots and roots of young plants. Effect of hyperthermia on cytokinin amount in plants grown from primed seeds was less pronounced compared with the plants grown from untreated seeds. So, cytokinins are considered an important regulator of rye plants’ response and adaptation to hyperthermia. Seed priming with cytokinins could be a relevant tool to improve growth and development of rye.