Inter- and Intraspecific Variation in the Germination Response to Light Quality and Scarification in Grasses Growing in Two-phase Mosaics of the Chihuahuan Desert
| Autor: | Fabiana Pezzani, Carlos Montaña |
|---|---|
| Rok vydání: | 2006 |
| Předmět: |
Phenotypic plasticity
Natural selection Light biology Ecology fungi Trichloris crinita food and beverages Genetic Variation Germination Original Articles Plant Science Poaceae biology.organism_classification Pleuraphis mutica Biological Evolution Intraspecific competition Chloris virgata Seeds Genetic variation Desert Climate Selection Genetic Mexico |
| Zdroj: | Annals of Botany. 97:1063-1071 |
| ISSN: | 1095-8290 0305-7364 |
| Popis: | • Background and Aims In many locations, plants are faced with adjacent, contrasting environments, and the between-species differential evolution of life history traits can be interpreted as an evolutionary response to this environmental heterogeneity. However, there has been little research on the intraspecific variability in these attributes as a possible evolutionary response of plants. • Methods In the two-phase mosaic of the Chihuahuan Desert (adjacent patches with contrasting resource availability), analyses were carried out of the germination response to the scarification and light quality to which grass seeds growing on these patches are exposed (open and closed habitats). • Key Results Species that grow in open habitats exhibited a higher germination success than those from closed habitats after scarification. At both the inter- and intraspecific level, there were differences in the germination percentage and in the germination speed in response to light quality. Intraspecific variation in the species from the closed habitat (Pleuraphis mutica and Trichloris crinita) and in Chloris virgata (which grows in both habitats) was due to genetic variation (the family factor was significant), but there was no genetic variation in phenotypic plasticity (non-significant interaction between family and light quality). In contrast, for the species that grows only in the open habitat (Dasyochloa pulchella), the family did not have a significant effect, but there was genetic variation in the phenotypic plasticity (significant interaction between family and light quality). • Conclusions In C. virgata, P. mutica and T. crinita, natural selection could be favouring those genotypes that responded better in each light environment, but it is not possible that the natural selection resulted in different optimal phenotypes in each habitat. On the contrary, in D. pulchella, selection could have reduced the genetic variation, but there is the possibility of the evolution of reaction norms, resulting in the selection of alternative phenotypes for each habitat. |
| Databáze: | OpenAIRE |
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