Antitranspirant treatment on bean plants to counteract cold stress

The aim of the work was to test the efficacy of the antitranspirant Scudotherm® in preventing cold damages on Phaseolus vulgaris L. Two tests were conducted: the first between June-July 2018, and the second between May-June 2019. Plants were grown in a greenhouse, in plastic pots (10 pots/treatment), on a peaty substrate. Treatments were carried out on three-week-old plants, by foliar application 24 hours before the stress. The experimental design included treatments with Scudotherm® at 2% compared to an untreated and unstressed control, and to an untreated but stressed control (controls were sprayed with tap water). The cold stress was induced by placing the plants at 3-4 °C, for 48 hours. Both in vivo and destructive analyzes were performed to evaluate the health status of plants, immediately after stress and after a one-week recovery period. The analyzes were performed on three biological replications. No significant effect of the treatments was observed on chlorophylls in vivo, chlorophyll a fluorescence parameters, secondary metabolites (anthocyanins and phenolic index), and lipid peroxidation. Significant variations were found in the metabolism of the sugars. Scudotherm® allowed maintaining the sucrose concentration similar to control and lower than stressed plants. During the first year, a similar behavior was also recorded for total sugars. These results suggested that Scudotherm® is able to mitigate some of the negative consequences of low temperatures, acting as a physical barrier on leaves, with an indirect physiological and biochemical effect.