Plant volatiles:
The plant volatilome is defined as the complex blend of volatile organic compounds
(VOCs) fed by different biosynthetic pathways and produced by plants… as a defense
strategy against biotic and abiotic stress (Maffei et al. 2007).
Volatilome = blend of volatile chemicals
Volatile organic compounds = chemicals that easily evaporate at room temperature, some of
which have odors/smells.
Biosynthetic pathways = chemical reactions
Biotic stress = damage from other living organisms (insects, animals, etc.)
Abiotic stress = damage from non-living surroundings (intense sunlight, wind, etc.)
What Causes That "Fresh Cut Grass" Smell?
http://mentalfloss.com/article/30573/what-causes-fresh-cut-grass-smell
Trauma, that’s what. It’s the smell of chemical defenses and first aid. The fresh, “green”
scent of a just-mowed lawn is the lawn trying to save itself from the injury you just
inflicted.
Leafy plants release a number of volatile organic compounds called green leaf volatiles
(GLVs). When the plants are injured, whether through animals grazing on them, you
cutting or mowing them, or even just unintentionally rough handling, these emissions
increase like crazy.
The rush of chemicals does a few things. Some of the compounds stimulate the
formation of new cells at the wound site so it closes faster. Others act as antibiotics that
prevent bacterial infection and inhibit fungal growth. A few spur the production of
defensive compounds at un-wounded sites as sort of a pre-emptive fortification. And still
others react with other chemicals to act as something like distress signals.
Scientists found in one study that the saliva of certain caterpillars reacts with the GLVs
released by coyote tobacco plants to make them attractive to the "big-eyed bugs" that
regularly eat the caterpillars.
Thankfully, the mix of lawnmower blades and GLVs won't get you eaten. Instead,
humans get a treat. Among the GLVs released by damaged grass are a group of eight
related oxygenated hydrocarbons, including aldehydes and alcohols, that cause the
“green odor.”
Plant Volatiles
Anthony Qualley, Purdue University, West
Lafayette, Indiana, USA
Natalia Dudareva, Purdue University, West
Lafayette, Indiana, USA
Published online: September 2010
Abstract
Plants produce an amazing number of
chemical compounds that can disperse
in the air at ambient temperature. These
plant volatiles have served mankind,
perhaps since pre‐Neolithic times, as
perfumes and flavor compounds.
In nature, these compounds attract
pollinators and seed dispersers, protect
plants through repulsion or intoxication
of attacking herbivores, entice predator
or parasitoid insects that prey on
herbivores, prime defenses of
neighboring plants against imminent
attack, confer antimicrobial properties
critical to defense against pathogens,
and mitigate oxidative stresses.
Plant volatiles are typically classified into
four major categories: terpenoids, fatty
acid derivatives, amino acid derivatives and phenylpropanoid/benzenoid compounds,
though a number of species‐ or genus‐specific volatile compounds, such as those found
in select species of Alliaceae and Brassicaceae, fall outside these categories. This
enormous variety is represented by more than 1700 compounds from 90 species.
Key Concepts:
 Plant volatiles are critical in the attraction of pollinators and seed dispersers.
 Plants use volatiles to protect themselves from pests and pathogens.
 Plants under herbivore attack can alert neighboring plant species, priming their
chemical defenses.
 Plant volatiles are classified according to their metabolic origins as terpenoids,
phenylpropanoids/benzenoids, fatty acid derivatives and amino acid derivatives.
 Biosynthesis of plant volatiles is spatially, developmentally and temporally regulated.
 Modern techniques for the collection and trapping of plant volatiles (SPME, dynamic
headspace sampling) provide sensitive and representative samples for analysis.
 Plant volatiles serve humankind as perfumes and aroma compounds, natural flavor
constituents, food additives/preservatives, and chemotherapeutics and anesthetics.