Revista Chilena de Historia Natural 76 (1): 129-137, 2003
RESEARCH ARTICLE
Phenotypic response of Lycopersicon chilense to water deficit
Environmental-induced phenotypic variation in plants is often considered to be a
functional response that maximizes fitness in heterogeneous environments. Lycopersicon chilense, a tomato species
endemic to Atacama Desert, shows altitudinal phenotypics variations in their natural environments, which could be due to different soil
water availabilities. It is hypothesized that (a) seeds coming from populations of different environments, cultivated in the same
environment, will have similar phenotypes, if populations are not genetically differentiated, and that (b) the different populations
subjected to two drought levels should vary their phenotypic constitution with respect to the control groups. The responses of twenty
phenotypic traits to different irrigation levels were studied in nine wild populations of Lycopersicon chilense. Seeds were
collected from populations along an altitudinal gradient (from 20 m to 3,075 m), transferred to a common environment and grown under
three soil water conditions: low (80 % FC), moderate (40 % FC) and severe (20 % FC). In spite of the climatic differences in their
natural habitat the phenotypic responses of plants growing in the same environment was similar in the nine populations. Significant
differences among populations were only observed in three out of twenty traits (fruit fresh weight, fruit volume and number of seeds per
fruit). Soil water deficit induced a phenotypic response in twelve characters; among these: root dry weight, cover, number of seeting
fruits and number of seeds per fruit showed the highest significance. An interaction between population and drought treatment was
found only for fresh weight of fruits, fruit volume and number of seeds per fruit. Our data indicate that the phenotypic response does not
differ among populations growing under similar environmental conditions. Probably the phenotypic response of L. chilense
in their natural habitats is related to physiological and metabolic adjustment rather than genetic variation.
Key words:
Lycopersicon
chilense, phenotypic response, water stress, physiological adjustment, self-organization, wild tomato
