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.