INVESTIGADORES
SOSA alejandro JoaquÍn
artículos
Título:
Patterns of morphological variation of alligator weed (Alternanthera philoxeroides): from native to invasive regions
Autor/es:
X. PAN; H.LIANG; A.J. SOSA; Y. GENG; B. LI; J. CHEN
Revista:
BIODIVERSITY SCIENCE
Editorial:
The Editorial Office of Biodiversity Science
Referencias:
Año: 2006 vol. 14 p. 232 - 240
ISSN:
1005-0094
Resumen:
The damage caused by biological invasions has traditionally been thought to result from alien species taking advantage of ecological differences between the native and introduced regions. In contrast, evidence is increasing that invasive plants can undergo rapid adaptive evolution during the process of range expansion. Using a common garden approach, we compared 19 morphological and anatomical traits of Al-ternanthera philoxeroides collected in native (Argentina) and invasive (China and USA) regions. The results show that native and invasive A. philoxeroides have become genetically differentiated. Populations from Ar-gentina had significant morphological variation in nine traits, with heritability varying from 49% to 89%. The nine traits are stomatal density, stomatal index, diameter of stem, diameter of pith cavity, thickness of vascular cylinder, thickness of cortex, area ratio of vascular cylinder, area ratio of pith cavity, and leaf index. However, populations from introduced regions showed no significant variations in any of the 19 traits, indi-cating that the morphological differences within introduced regions might be based on phenotypic plasticity. Based on the result of PCA (primary component analysis), all five introduced populations and one population from Argentina (Santa Fé, 59°49′W, 29°16′S) can be clustered as one group, implying that the Santa Fé population may have similar genotypes with the lineage introduced to China. The existence of genetically differentiation of A. philoxeroides between native and introduced regions should be considered in any pro-grams that attempt management or utilization of this plant.