This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: High temperatures can significantly impair the growth and yield of crops, including tomatoes. A new study by an international research team led by Dr.
Justyna Olas, of the Leibniz Institute for Horticultural Sciences (IGZ), has shown that tomatoes can respond better to subsequent heat stress following moderate heat exposure. The work is published in The Plant Journal. Thermal priming reprograms plants in response to an initial moderate heat stress, allowing them to retain a memory of the stress event for several days and to respond more rapidly and effectively to subsequent heat stress.
The researchers initially studied tomato plants of the 'Moneymaker' cultivar under controlled conditions. Following moderate heat exposure, the plants were subjected to severe recurrent heat stress several days later. While nonprimed plants suffered substantial damage, plants previously exposed to moderate heat were better able to withstand the stress.
The protective effect of 'priming' lasted longer than in the model plant Arabidopsis thaliana: a measurable protective effect was still present after a 10-day interval between the initial heat exposure and the recurrent heat stress. However, this effect decreased as the memory phase became longer and was no longer detectable after 20 days. The study therefore shows that the duration of thermal memory differs between plant species.
The subsequent effect on productivity is particularly relevant for horticulture. Under controlled conditions, plants exposed to moderate heat and subsequently subjected to recurrent severe heat stress produced, on average, 41% more fruit than non-heat-stressed control plants. Total fruit mass was also higher, suggesting that thermally primed plants produced higher yields after recurring heat stress.
Analyses of β-carotene and lutein as quality markers likewise showed no significant differences, indicating that fruit quality was not affected. The effect was also observed under uncontrolled environmental conditions. In a field experiment conducted in 2025 in Großbeeren, plants that were initially exposed to moderate heat and subsequently subjected to recurrent heat stress produced around 53% more fruit than non-heat-stressed control plants.
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