Environmental Engineering Reference
In-Depth Information
FIGURE 14.3
Se.hyperaccumulator.
S. pinnata
.growing.in.its.natural.habitat.and.some.of.its.natural.ecological.
partners..Plant.Se.accumulation.has.been.shown.to.protect.against.herbivory.by.grasshoppers.
(top.left).and.prairie.dogs.(bottom.right).and.to.reduce.infestation.with.root.nematodes.(bottom.
center)..Some.ecological.partners.appear.to.have.evolved.Se.tolerance,.such.as.a.diamondback.
moth.(top.center).and.native.bumblebees.(top.right),.as.well.as.certain.nematodes.and.certain.
neighboring.plant.species.(bottom.left).
harbored. fewer. arthropod. species. and. individuals. in. their. natural. habitat.
than.comparable.Se.nonaccumulators.(Galeas.et.al..2008).
While.methyl-SeCys.is.not.toxic.by.itself,.herbivores.that.ingest.hyperac-
cumulator. plant. material. readily. demethylate. it. to. SeCys. (Freeman. et. al..
2006b),. which. is. toxic. because. of. its. nonspeciic. incorporation. into. pro-
teins.. Thus,. Se. hyperaccumulation. is. an. effective. plant. defense. mecha-
nism.against.herbivory..For.most.plant.defenses,.over.time.some.herbivores.
evolve.tolerance..This.is.also.true.for.Se.hyperaccumulation..A.population.
of. diamondback. moths. living. in. a. seleniferous. area. on. hyperaccumulator.
S. pinnata
. was. shown. to. be. completely. Se. tolerant. (Freeman. et. al.. 2006b)..
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