Leaf Vein Morphological Variation in Four Endangered Neotropical Magnolia Species along an Elevation Gradient in the Mexican Tropical Montane Cloud Forests.

Ernesto C Rodríguez-Ramírez,Leccinum J García-Morales,J Antonio Vázquez-García,Othón Alcántara-Ayala,Isolda Luna-Vega

doi:10.3390/plants10122595

Abstract

Climatic variations influence the adaptive capacity of trees within tropical montane cloud forests species. Phenology studies have dominated current studies on tree species. Leaf vein morphology has been related to specific climatic oscillations and varies within species along altitudinal gradients. We tested that certain Neotropical broad leaf Magnolia species might be more vulnerable to leaf vein adaptation to moisture than others, as they would be more resilient to the hydric deficit. We assessed that leaf vein trait variations (vein density, primary vein size, vein length, and leaf base angle) among four Magnolia species (Magnolia nuevoleonensis, M. alejandrae, M. rzedowskiana, and Magnolia vovidesii) through the Mexican Tropical montane cloud forest with different elevation gradient and specific climatic factors. The temperature, precipitation, and potential evaporation differed significantly among Magnolia species. We detected that M. rzedowskiana and M. vovidesii with longer leaves at higher altitude sites are adapted to higher humidity conditions, and that M. nuevoleonensis and M. alejandrae inhabiting lower altitude sites are better adjusted to the hydric deficit. Our results advance efforts to identify the Magnolia species most vulnerable to climate change effects, which must focus priorities for conservation of this ecosystem, particularly in the Mexican tropical montane cloud forests.

Highlights

Climate variations trigger morphological leaf variations in the Tropical montane cloud forest (TMCF) [1,2]
Leaf morphology varies within species across elevation gradients, and broader leaves are more susceptible to temperature extremes [7,8]
We addressed the following questions: (1) Are there significant differences between leaf vein among four Magnolia species restricted to the Mexican tropical montane cloud forests? (2) Is there a leaf vein anatomy adaptation that allows each Magnolia species to be resilient to specific climatic factors? (3) Are there specific climatic factors that influence variation in leaf vein traits throughout an elevation gradient?

Summary

Introduction

Climate variations trigger morphological leaf variations in the Tropical montane cloud forest (TMCF) [1,2]. A range of morphological evidence strongly suggests that leaf vein morphology is adapted to climate [3]. Intraspecific foliar vein variation in high moisture environments is necessary for developing hypotheses regarding adaptive patterns in response to climatic oscillations and elevation gradients [4,5]. Leaf morphology varies within species across elevation gradients, and broader leaves are more susceptible to temperature extremes [7,8]. This variation could be indicative of predicting how species will eventually respond to climate change [9]. Current research indicates that climate phenomena are more widespread than previously considered in TMCF [10,11]

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Results

Conclusion