Effect of low-intensity ultrasound on membrane integrity of suspension-cultured parsley cells (Petroselinum crispum L.)

The ability to sense and respond to physical stimuli is an important key of the life. It was recognized that ultrasound as a physical stimulus could produce drastic changes in biological systems. High-intensity ultrasound is well known to be destructive to biological materials, but low-intensity ultrasound, on the other hand, has shown a range of biological effects with potential significance in biotechnology. One of the most studied effects of ultrasound on living cells is the increase in their membrane permeability, enhancing the uptake of foreign substances and the release of intracellular products into the media. In the present research suspension-cultured parsley cells were treated with ultrasound at 29 kHz with the power of 455 mW/cm3, for 10, 20, and 40 min. The viability of cells was examined using Evanꞌs blue dye. Alteration of membrane permeability was evaluated by measuring the lipid peroxidation rate and leakage of electrolytes such as Ca2 and K from membranes to the extracellular medium. According to the results exposure to ultrasound for 10 and 20 min neither changed the viability of the cells nor lipid peroxidation of the membranes. Exposure of parsley cells to ultrasound for 40 min however, decreased the viability and increased the release of K to the extracellular medium. The results suggest that low dosage of ultrasound energy dose not adversely affect the membrane integrity of parsley cells and also stimulates their growth.