Journal of Plant Research

, Volume 129, Issue 5, pp 863–872

A δ15N assessment of nitrogen deposition for the endangered epiphytic orchid Laelia speciosa from a city and an oak forest in Mexico

  • Edison A. Díaz-Álvarez
  • Casandra Reyes-García
  • Erick de la Barrera
Regular Paper

DOI: 10.1007/s10265-016-0843-y

Cite this article as:
Díaz-Álvarez, E.A., Reyes-García, C. & de la Barrera, E. J Plant Res (2016) 129: 863. doi:10.1007/s10265-016-0843-y

Abstract

Atmospheric nitrogen deposition poses a major threat to global biodiversity. Tropical epiphytic plants are especially at risk given their reliance on atmospheric sources of nutrients. The leaf, pseudobulb, and root carbon and nitrogen content, C:N ratio, as well as the nitrogen isotopic composition were studied for individuals of Laelia speciosa from a city and from an oak forest in Mexico. The nitrogen content of leaves was similar between the city and the oak forest, reaching 1.3 ± 0.2 % (dry mass). The δ15N of leaves, pseudobulbs, and roots reached 5.6 ± 0.2 ‰ in the city, values found in sites exposed to industrial and vehicular activities. The δ15N for plant from the oak forest amounted to –3.1 ± 0.3 ‰, which is similar to values measured from sites with low industrial activities. Some orchids such as Laelia speciosa produce a single pseudobulb per year, i.e., a water and nutrient storage organ, so the interannual nitrogen deposition was studied by considering the ten most recent pseudobulbs for plants from either site formed between 2003 and 2012. The C:N ratio of the ten most recent pseudobulbs from the oak forest, as well as that of the pseudobulbs formed before 2010 for plants in the city were indistinguishable from each other, averaging 132.4 ± 6.5, while it was lower for the two most recent pseudobulbs in the city. The δ15N values of pseudobulbs from the oak forest averaged ‒4.4 ± 0.1 ‰ for the entire series. The δ15N ranged from 0.1 ± 1.6 ‰ for the oldest pseudobulb to 4.7 ± 0.2 ‰ for the pseudobulb formed in the city from 2008 onwards. Isotopic analysis and the C:N ratio for L. speciosa revealed that rates of nitrogen deposition were higher in the city than in the forest. The δ15N values of series of pseudobulbs showed that it is possible to track nitrogen deposition over multiple years.

Keywords

Atmospheric pollution Conservation physiology Global change Industrial activities Neo-Volcanic axis 

Funding information

Funder NameGrant NumberFunding Note
Consejo Nacional de Ciencia y Tecnología
  • Beca doctoral
Dirección General Asuntos del Personal Académico, Universidad Nacional Autónoma de México
  • PAPIIT IN205616

Copyright information

© The Botanical Society of Japan and Springer Japan 2016

Authors and Affiliations

  • Edison A. Díaz-Álvarez
    • 1
    • 2
  • Casandra Reyes-García
    • 3
  • Erick de la Barrera
    • 2
  1. 1.Posgrado en Ciencias BiológicasUniversidad Nacional Autónoma de México, Ciudad UniversitariaMéxicoMexico
  2. 2.Instituto de Investigaciones en Ecosistemas y SustentabilidadUniversidad Nacional Autónoma de MéxicoMoreliaMexico
  3. 3.Centro de Investigación Científica de YucatánMéridaMexico

Personalised recommendations