Fructan metabolism in two species of Bromus subjected to chilling and water stress

Abstract

Two species of Bromus adapted to different climatic conditions were studied to determine their responses to chilling and water stress. Enzymes of sucrose and fructan metabolism as well as fructoside content were measured in roots and shoots. The results indicate that Bromus pictus (adapted to a cold desert area) has a constitutive fructan synthesis, whilst B. auleticus (adapted to a warmer northern climate) only accumulated fructan under cold stress. Microscopic observations of roots exposed to fluorescent probes ascertained cell viability and showed that the apex of roots in the northern species were more affected by the water-deficit treatment than the southern species. The presence of fructans in B. pictus and their absence in B. auleticus support the hypothesis that fructans play a role in plant tolerance to environmental stress.