Physiological characterizations of three barley genotypes in response to low potassium stress

Abstract

Plants adopt several strategies for fighting against low potassium (LK) stress. Our previous study identified some Tibetan wild barley accessions which show the higher LK tolerance than cultivated barley. However, the physiological mechanisms underlying the wild barley are not well understood. In this study, growth performance, elements content, SPAD value, photosynthetic parameters, and ATPase activities were measured to investigate the effect of LK stress on the two wild barley genotypes (XZ153 and XZ141) and one barley cultivar (ZD9) differing in LK tolerance. The results revealed that LK stress inhibited barley growth and induced reduction in dry weight, with XZ153 being least inhibited. Moreover, XZ153 had less reduction in photosynthetic rate, SPAD value, and K concentrations in the younger leaves under LK stress compared to the other two genotypes. Although the activities of H+/K+-ATPase and Ca2+/Mg2+-ATPase were increased significantly in all three genotypes in response to LK, the highest H+/K+-ATPase activity was observed in XZ153. The current results indicate that higher LK tolerance of XZ153 is partly attributed to its high capacity of transferring K from the old leaves to younger ones.