Leaf carbon assimilation and molecular phylogeny in Cattleya species (Orchidaceae)

V. Andrade-Souza, A.-A.F. Almeida, R.X. Corrêa, M.A. Costa, M.S. Mielke, F.P. Gomes
Published: August 11, 2009
Genet. Mol. Res. 8 (3) : 976-989
DOI: https://doi.org/10.4238/vol8-3gmr618

Cite this Article:
V. Andrade-Souza, A.A.F. Almeida, R.X. Corrêa, M.A. Costa, M.S. Mielke, F.P. Gomes (2009). Leaf carbon assimilation and molecular phylogeny in Cattleya species (Orchidaceae). Genet. Mol. Res. 8(3): 976-989. https://doi.org/10.4238/vol8-3gmr618

About the Authors
V. Andrade-Souza, A.-A.F. Almeida, R.X. Corrêa, M.A. Costa, M.S. Mielke, F.P. Gomes

Corresponding Author
A.-A.F. Almeida
Email: alexalan@uesc.br

ABSTRACT

We examined leaf CO₂ assimilation and how it varied among species within the orchid genus Cattleya. Measurements of CO₂ assimilation and maximum quantum yield of PS II (Fv/Fm) were made for mature leaves of nine species using a portable system for photosynthesis measurement and a portable fluorometer. Leaf area was measured with an area meter, and the specific leaf mass was determined. DNA of nine Cattleya species and two species of Hadrolaelia was extracted using the CTAB protocol. Each sample was amplified and sequenced using primers for the trnL gene. The phylogenetic analyses, using neighbor-joining and maximum parsimony methods, retrieved a group that included Cattleya and Hadrolaelia species, in which the unifoliate species were separated from the bifoliates. The topologies of the two cladograms showed some similarities. However, C. guttata (bifoliate) was placed in the unifoliate clade in the neighbor-joining tree, while C. warneri (unifoliate) was not placed in this clade in the maximum parsimony tree. Most Cattleya species keep the leaf stomata closed from 6 am to 4 pm. We suggest that C. elongata, C. tigrina and C. tenuis have C₃-crassulacean acid metabolism since they open their stomata around 12 am. The Fv/Fm values remained relatively constant during the measurements of CO₂ assimilation. The same was observed for the specific leaf mass values, although great variations were found in the leaf area values. When the species were grouped using molecular data in the neighbor-joining analysis, no relation was observed with CO₂ assimilation.