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Selected Works

Ed L. Frederickson

Plant Sciences

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Articles 1 - 3 of 3

Full-Text Articles in Agriculture

Within-Plant Distribution Of Volatile Compounds On The Leaf Surface Of Flourensia Cernua, Rick Estell, Darren James, Ed Frederickson, Dean Anderson May 2013

Within-Plant Distribution Of Volatile Compounds On The Leaf Surface Of Flourensia Cernua, Rick Estell, Darren James, Ed Frederickson, Dean Anderson

Ed L. Frederickson

We are using Flourensia cernua as a shrub model to study how terpenes affect livestock herbivory. Two experiments were conducted to examine distribution of volatile chemicals within a plant in an effort to minimize sample variability. In Experiment 1, leaves (current year's growth) were collected from 20 tarbush plants. Two leaders were sampled from each of three positions (outer canopy, subcanopy, and basal) in all four quadrants (based on ordinal direction). In Experiment 2, 10 leaders of current year's growth were removed from another 20 plants. Leaders were collected from the outer canopy of each quadrant and separated into thirds …


A Retention Index Calculator Simplifies Identification Of Plant Volatile Organic Compounds, Ed Frederickson Dec 2008

A Retention Index Calculator Simplifies Identification Of Plant Volatile Organic Compounds, Ed Frederickson

Ed L. Frederickson

Plant volatiles (PVOCs) are important targets for studies in natural products, chemotaxonomy and biochemical ecology. The complexity of PVOC profiles often limits research to studies targeting only easily identified compounds. With the availability of mass spectral libraries and recent growth of retention index (RI) libraries, PVOC identification can be achieved using only gas chromatography coupled to mass spectrometry (GCMS). However, RI library searching is not typically automated, and until recently, RI libraries were both limited in scope and costly to obtain. Objective To automate RI calculation and lookup functions commonly utilised in PVOC analysis. Methodology Formulae required for calculating retention …


Volatile Compounds On The Leaf Surface Of Intact And Regrowth Tarbush (Flourensia Cernua Dc) Canopies, Ed Frederickson, R. Estell, M. Remmenga Dec 2006

Volatile Compounds On The Leaf Surface Of Intact And Regrowth Tarbush (Flourensia Cernua Dc) Canopies, Ed Frederickson, R. Estell, M. Remmenga

Ed L. Frederickson

Shrub expansion into desert grasslands is a serious problem resulting in loss of forage and rangeland productivity. Flourensia cernua DC (tarbush) is one such shrub contributing to the decline of Chihuahuan Desert grasslands. Our previous research has shown tarbush consumption by sheep and goats to be negatively related to leaf surface concentration of individual terpenes and epicuticular wax. Concentrations of compounds such as terpenes often change with plant age and phenology. Our objective was to examine the effect of altering the vegetative state of tarbush on volatile chemicals. Ninety tarbush plants were randomly selected, and all biomass within 10 cm …