Abstract
<jats:p>A study was carried out to verify the effects of PEG-6000-induced osmotic shock on Italian ryegrass physiological processes and protein profiles determined by the microfluidic electrophoresis technique towards improving knowledge on the behavior of the species under drought. Sensitivity to osmotic shock was revealed by drastic drops in FW (fresh weight) and DW (dry weight) of most plant parts, chlorophyll content, shoot and root length, leaf area, leaf area ratio, specific leaf area and other physiological measures. As stress was intensified, there were reductions in leaf and solution ψs and osmotic adjustment was detected. Despite this reaction, the 0.97 MPa PEG-6000 treatment caused all plants to die within the last week of each trial. Electrophoresis analyses evidenced four 20.3, 24.4, 51.4 and 55.2 kDa protein bands whose peak areas increased sharply with stress from 0.25 MPa onwards. It is concluded that Italian ryegrass is readily injured by osmotic shock, and the damage is accompanied by the upregulation of four proteins. Further work to identify these proteins may offer new insights into understanding the species' initial responses to water deficit. The results obtained in this study open new perspectives for mitigating drought effects in Italian ryegrass.</jats:p>