FRUCTAN METABOLISM IN 2 SPECIES OF BROMUS SUBJECTED TO CHILLING AND WATER-STRESS

Two species of Bromus adapted to different climatic conditions were st udied to determine their responses to chilling and water stress. Enzym es of sucrose and fructan metabolism as well as fructoside content wer e measured in roots and shoots. The results indicate that Bromus pictu s (adapted to a cold desert area) has a constitutive fructan synthesis , whilst B. auleticus (adapted to a warmer northern climate) only accu mulated fructan under cold stress. Microscopic observations of roots e xposed to fluorescent probes ascertained cell viability and showed tha t the apex of roots in the northern species were more affected by the water-deficit treatment than the southern species. The presence of fru ctans in B. pictus and their absence in B. auleticus support the hypot hesis that fructans play a role in plant tolerance to environmental st ress.