Nitrogen (N) in the Environment
~It's everywhere!
~Often the limiting factor in terrestrial systems
Biological Nitrogen Fixation (BNF)
~Symbiotic nitrogen (N) fixation occurs in root nodules
~Energetically costly, but strong competitive advantage
Fixation Strategies
~Spectrum of regulation- Facultative to Obligate
Hawai‘i Pacific Weed Risk Assessment System (HPWRA)
~Tool to help predict whether a plant will likely become invasive
~Uses published research and experts to answer 49 ?????
~High Risk or Low Risk evaluation
Seed collection & germination
~Extract seeds from pods
~Scarify and imbibe seeds
~Sew
Growth & measurements
~Repot seedlings
~Randomized block design
~Fertilization
~Stem diameter, height, & number of leaves
Harvest
~Separate plant parts: roots, shoots, & root nodules
~Take dry mass measurements & grind
~Elemental analyzer & Isoptope ratio mass spectrometer
High Risk
~Acacia confusa
~Falcataria moluccana
~Leucaena leucocephala
~Senna siamea (control)
Low Risk
~Caesalpinia pulcherrima
~Pterocarpus indicus
~Samanea saman
~Bauhinia variegata (control)
Coming up...
~Four more species of each High Risk & Low Risk
~Data analysis
Thank You!
Dr. Rebecca Ostertag, UHH
Dr. Jennifer Funk, Chapman University
Dr. Jon Price, UHH
Molly Murphy, BIISC