Induction of Time-Dependent Tolerance through Thermopriming in Tomatoes

Abstract

The risk of potential yield losses due to heat waves and other challenging weather phenomena is globally increasing. So far, plant producers have only had limited possibilities to adapt their cultivation methods. Plants exposed to (any form of) stress naturally adapt to environmental changes by synthesizing and accumulating protective metabolites to become more tolerant to subsequent stress events. Priming, or thermopriming if induced by heat, relies on this concept to increase plant tolerance. However, it is still unclear how to apply heat stress under consideration of plant physiological costs and benefits in regard to the further development and growth of plants. In this study, 90 min thermopriming (at 40 °C) for seven consecutive days induced an accumulation of flavonols in leaves that were directly affected by the treatment and thus identified as suitable for inducing thermotolerance in tomato var. Adeleza seedlings. The initial costs on plant growth and development were compensated a few weeks after thermopriming and even benefited the plants later. Thereby, thermopriming may enable global plant production to cope with unpredictable and more frequently occurring environmental stress by a sustainable hardening method of seedlings that can be incorporated in the plant production cycle.