Quantitative Evaluation of Hybrid Aspen Xylem and Immunolabeling Patterns Using Image Analysis and Multivariate Statistics

In this study we present a method for quantitative evaluation of hybrid aspen genotypes xylem morphology and immunolabeling microdistribution. The method is based on image analysis and multivariate statistical evaluation of light and immunofluorescence microscopy images of wood xylem cross sections. The selected immunolabeling antibodies targeted five different epitopes present in the aspen xylem cell walls. Twelve down-regulated hybrid aspen genotypes have been included in the method development. The twelve knock-down genotypes were selected based on pre-screening by pyrolysis-IR of global chemical content. The multivariate statistical evaluations successfully identified comparative trends for modifications in the down-regulated genotypes compared to the unmodified control, even when no definitive conclusions could be drawn from individual studied variables alone. Of the twelve genotypes analysed, three genotypes showed significant trends for modification in both morphology and immunolabeling. Six genotypes showed significant trends for modification in either morphology or immunocoverage. The remaining three genotypes did not show any significant trends for modification.