Ca. Busso et al., DRY-WEIGHT PRODUCTION AND PARTITIONING IN MEDICAGO-MINIMA AND ERODIUM-CICUTARIUM UNDER WATER-STRESS, Annals of botany (Print), 82(2), 1998, pp. 217-227
Medicago minima and Erodium cicutarium are two naturalized annual spec
ies in extensive semi-arid, temperate rangelands of central Argentina.
A field study was conducted during 1989 and 1990 to evaluate the effe
cts of different levels of soil water availability on above- and below
-ground dry weight production and partitioning in these species. Dry w
eight production by M. minima was more sensitive to water stress than
that by E. cicutarium. Although the response was more marked in M. min
ima, both species allocated a larger proportion of total plant dry wei
ght to fruits under water stress than under irrigated conditions durin
g early spring. Percentage allocation of total plant dry weight into r
eproductive organs in both species, and stems and peduncles in E. cicu
tarium, was correlated with total dry weight of these organs; this mig
ht indicate a correlation between sink size and strength. Persistence
of both species in the local flora appears to be associated with their
capacity to colonize open, degraded areas and grow in association wit
h native perennial grasses, as well as to tolerate severe drought peri
ods. (C) 1998 Annals of Botany Company.