The effect of salicylic acid on biomass and MDA concentration in Ocimum basilicum and Thymus vulgaris leaves under different climate conditions

Abstract

The global climate changes are becoming more and more important recent years. So, it is important to identify and discuss how these factors affect physiological, morphological and biochemical parameters of herbal plants. There are many studies of different effects of climate change on crops, food quality or weeds. However, there are almost none researches how with salicylic acid (SA) treated plants will respond to elevated climatic conditions and drought stress. The aim of this research was to investigate the effect of SA on biomass and oxidative stress caused lipid peroxidation in basil (Ocimum basilicum L.) and thyme (Thymus vulgaris L.) leaves under different climate conditions. The plants were grown in automatically controlled climatic conditions under current (400 ppm CO2, 21/14 ºC, day/night) and warmed (800 ppm CO2, 25/18 ºC) climates, and well-watered and drought stressed conditions. Half of the plants were sprayed with 2mM SA, other – with distillated water. There was obtained, that warmed climate increased the growth of both investigated plant and the effect was more pronounced for basil. Drought stress was decreasing growth parameters of basil, while for thyme the opposite tendency was detected. Salicylic acid effect on dry biomass of both plants was week and statistically insignificant in almost all treatment variants, with exception for basil grown under warmed climate, when dry biomass of plants sprayed with SA increased and decreased significantly (p<0.05) for well-watered and drought stressed plants respectively, compare to non-sprayed. Lipid peroxidation indicator, malondialdehyde (MDA) concentration, was increasing under drought stress effect in both investigated plants and under both climates. The effect of SA on malondialdehyde concentration in plants leaves was slightly different from the effect on dry biomass. The changes of MDA concentration were more pronounced for thyme than basil.[...]