Isothermal microcalorimetry allows detection of ‘aquaporines’ in quinoa seeds

Aquaporines are channels specifically involved in the overall transport of water through plasma membrane and tonoplast cells. In order to test their presence in quinoa (Chenopodium quinoa Willd.) seeds, we used isothermal microcalorimetry to monitor germination and root elongation processes. Measurements were made in the presence of distilled water or HgCl2 solution, which inhibits the function of aquaporines. When the seeds were allowed to take up water in the presence of the mercury salt, lower values were found for the specific thermal power, from the beginning of the process, as compared with results of the control experiments. The inhibition by the mercurial solution was reverted by EDTA and thiourea solutions.