Thursday, August 9, 2007

PS 66-129: Spectroscopic analysis of chlorophyll, carotenoids, nitrogen, and separability of two neotropical dioecious tree species

Pablo Arroyo, University of Connecticut, Jolene E. Trujillo, University of New Mexico, Margaret Kalacska, Simon Fraser University, Ben Caraballo, New York University, and Orlando Vargas, La Selva Biological Station.

The expression of gender in the spectral properties and leaf chemistry was examined for Hyeronima alchorneoides and Virola koschnyi, two Neotropical dioecious tree species. Spectral Vegetation Indices (SVIs), pattern classifiers, Brattacharrya test statistic, Wilcoxon ranksum tests and the t-test were used to determine differences between leaves from the two genders. 20 leaves from nine trees (five females, 4 males) of each species were collected and the spectral signature was measured with the ASD FieldSpec Handheld spectrometer. Subsequently, a subset of 48 leaves from the 180 were cored and pigments were extracted to determine chlorophyll a, chlorophyll b, and carotenoid content. Nitrogen content was also determined. The SVIs indicated differences between male and female leaves for both H. alchorneoides and V. koschnyi, as did the pattern classifiers with 7.1 % error for H. alchorneoides and 5.3% error for V. koschnyi. Differences were also found for Chlorophyll a, Chlorophyll b, total Chlorophyll, carotenoids and nitrogen content among the genders.