Abstract

VILLAMIZAR CUJAR, JAVIER MAURICIO; RODRIGUEZ LOPEZ, NELSON FACUNDO  and  TEZARA FERNANDEZ, WILMER. Phenotypic Plasticity in Plants of Lippia dulcis (Verbenaceae) Subjected to Water Deficit. Acta biol.Colomb. [online]. 2012, vol.17, n.2, pp.365-380. ISSN 0120-548X.

Phenotypic plasticity (FP) is one of the mechanisms by which plants can respond to environmental heterogeneity by adjusting their morphology and physiology. This study tested and quantified the FP of Lippia dulcis plants in response to water availability in soil (low, medium and high), on morphologic and biomass allocation traits during the vegetative ontogeny (days 39, 45, 59 and 66). We hypothesized that in response to water availability, a higher FP should be expected in morphological compared to biomass allocation traits. The leaf mass fraction, leaf area ratio, branch length, number of leaves and root mass/leaf mass ratio, showed the largest capacity of plastic adjustment in the L. dulcis plants to water deficit, whereas the specific leaf area represented the trait with the lowest FP along vegetative ontogeny. The magnitude and pattern of FP changed depending on trait, water availability and ontogenic development. Contrary to our hypothesis the morphological traits and biomass allocation traits showed equivalent FP. The models of optimum allocation and optimum foraging are not mutually exclusive under water deficit. L. dulcis changed its pattern of biomass allocation, leaf and root morphology and as an adaptive advantage optimized the balance between organs involved in water acquisition and use. L. dulcis showed a remarkable ability to avoid water deficit.

Keywords : Lippia dulcis; phenotypic plasticity; biomass allocation; water deficit; ontogeny.

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