LAUSR

Abstract 24-epibrassinolide (24-EBL) is plant steroid hormone that can regulate several physiological effects in plants, including promotion of cell growth and induction of heat stress tolerance. The purpose of this work is to investigate the influence of various concentrations of 24-EBL on the dehydration mechanism of seedlings of two maize hybrids (ZP434 and ZP704). Control and treated samples were subjected to isothermal conditions for dehydration processes. The effects of carbohydrates and mineral contents on the possible changes in the dehydration mechanism (from kinetics standpoint) were investigated. Comparing control samples to samples treated with 24-EBL, it was found that different dehydration mechanisms exist. The differences arise from the influence of 24-EBL, that causes a significant increase of phosphorus values for ZP704, whilst the reverse was identified for ZP434. It was assumed that the plumule sensitivity to dehydration stress originates from the interaction of water with primary amino groups as cations in polyamines, for lower concentrations of 24-EBL. It was found that the temperature variation (105–130 °C) leads to situations where trehalose does not arrive fast enough to “replace the water”, because its handicap to binds (by hydrogen bonds) to biomolecules instead of water. It was found that 24-EBL cause changes of carbohydrates properties, which are important for the defense mechanism from environmental stresses.