Influence of Cobalt, Cesium, and Combined Stresses on Physiological Parameters and Gene Expression of Two Hullless Barley Varieties.

This study investigated the impact of cobalt and cesium stresses on two hulless barley varieties through a hydroponic experiment. The plants were exposed to 200 μM cobalt chloride (Co), 200 μM cesium chloride (Cs), or with concurrent exposure to 100 μM Co + 100 μM Cs. The findings revealed that exposure to Co and Cs, either alone or in combination, caused a substantial reduction in plant growth and weight. Interestingly, the hulless barley seedlings were found to be more resilient to Cs stress, attributed to its lower Cs enrichment factor. The stressed seedlings demonstrated increased oxidative stress levels (malondialdehyde, proline, and content), but also displayed increased activity of antioxidant enzymes (POD and SOD), active oxygen scavenging capacity (GSH and GSSG content), and gene expression (GSH2, POD and SOD), reflecting a plant defense mechanism. Moreover, the expression of PAL and P5CS genes was significantly enhanced in seedlings under Co, Cs, and (Co + Cs) treatments, providing a basis for the physiological mechanism of heavy metal resistance in hulless barley. The results of this study provide valuable insights into the mechanisms of heavy metal resistance in hulless barley, indicating the plant's potential for phytoremediation. [ABSTRACT FROM AUTHOR]