Variación morfo-anatómica de Ribes ciliatum a lo largo de un gradiente altitudinal en el norte de la Sierra Nevada, México

Abstract

The species distribution along altitudinal gradients is associated with climate changes, promoting changes in the morphology and anatomy of the species. In this study, the morpho-anatomical changes of leaf and wood of Ribes ciliatum (Grossulariaceae) were evaluated along an altitudinal gradient in Tlaloc Mount, at the northern region of Sierra Nevada, State of Mexico. The samples were collected from 2,949 m up to 3,545 m elevation. Leaf and wood permanent slides were prepared to describe and quantify characters. Variance and multiple regression analyses were performed. Ribes ciliatum showed a decrease in the plant size and probably it is explained by the low temperatures, the high light intensity, and poor soils. Some leaf and wood characters showed a decrease in the site of higher elevation. However, for palisade parenchyma width, stomata density, vessel density, and number of rays, the decrement was gradual as it has been reported for other species. Multiple regressions revealed that altitude was the variable that better predicts these four variables together with canopy density, organic matter, and soil humidity. In the case of wood, the reduction on vessel density with narrower vessels and narrower width rings are considered modifications to survive under those environmental conditions allowing the plants to maintain water movement and avoid embolisms. In addition, the occurrence of paedomorphic rays at the highest elevation site is interpreted as a trait for storage. The morpho-anatomical variation found in R. ciliatum is not linear in most variables evaluated as it is reported for other species growing outside the Neotropics.