This document discusses plant defenses against pests and invaders. It begins by explaining why understanding plant defenses is interesting and may improve gardening. It then discusses how plants are primary producers but also protect themselves through physical barriers and defense chemicals. Many defense chemicals are phytochemicals that plants use for chemical warfare. The document focuses on the allelochemical juglone produced by walnut trees, which is toxic to many other plants and insects but stored in walnut trees in a non-toxic form. Understanding plant defenses can help gardeners deal with issues like allelopathy. The document concludes by mentioning some other native plants with allelopathic properties.

1. 3/11/2013
Out of the Wilds and Into Your Garden
Gardening with California Native Plants in Western L.A. County
Project SOUND – 2013 (our 9th year)
© Project SOUND
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2. 3/11/2013
Warfare in the Garden
how plants protect themselves
from pests and invasions
C.M. Vadheim and T. Drake
CSUDH & Madrona Marsh Preserve
Madrona Marsh Preserve
March 2 & 5, 2013
© Project SOUND
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3. 3/11/2013
Why consider plant defenses?
 Plants – and everything about them – are inherently
interesting
 Understanding how plants interact with other living things
may improve your gardening
 Plants and animals are more similar than we think – at least
at the cellular level
 May suggest novel medicines, pesticides and other useful
prodcucts
© Project SOUND
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4. 3/11/2013
Plants are primary producers
Photosynthesis:
stored energy,
other (biomass)
http://www.bostonbakesforbreastcancer.org/summer-sun-radiation-and-chemo/
http://www.glogster.com/beckeyy/food-web/g-6mp96eehhgdfvco22h8bna0
 That means they are ‘food’ to many organisms
© Project SOUND
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5. 3/11/2013
But plants aren’t merely generous benefactors
or faithful servants….
http://thebillfold.com/2012/04/reader-mail-how-to-be-a-generous-person/
© Project SOUND
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6. 3/11/2013
After all, plants have to live too…
 Capturing energy needed for life
(photosynthesis)
 Obtaining water: roots
 Obtaining nutrient chemicals
(primarily through the roots)
 Reproducing: seed or vegetative
 Protecting themselves from
anything that impacts the above:
 Abiotic factors: temperature,
weather, soils etc.
 Biotic factors: living things
CA Goldenrod - Solidago californica
© Project SOUND
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7. 3/11/2013
Plants are far more
complex than most
of us realize
 They interact with many types of
organisms – for better or worse
 They are at least as complex as
higher animals
 They were not set on this planet
for our use alone
http://img.ehowcdn.com/article-
new/ehow/images/a08/4f/it/avoid-leggy-seedling-
800x800.jpg
 They often behave more like
plant warriors than like shrinking
violets
© Project SOUND
http://gorillaartfare.com/character-design/two-little-kittens/
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Types of defenses
 Physical barriers (preformed or
induced)
 Waxy cuticle
 Trichomes/leaf hairs
 Tough epidermis
 Sticky gums & resins
 Prickles, barbs and thorns
 Dense growth habit
 Hard covering to protect seeds
 Etc.
 Defense chemicals
 Preformed: always ready
 Induced: produced only when
needed (usually when stimulated
by an attack)
© Project SOUND
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9. 3/11/2013
Phytochemicals: the basis of plant chemical warfare
 Phytochemicals: non-nutritive
plant metabolites that are
essential for the survival and
proper functioning of growth and
reproduction in plants
 Often involved in protection
against herbivores, pests and
micro-organisms (or other
environmental stresses)
 Sometimes used by animals that
eat them:
http://naturallyjodi.blogspot.com/2012/08/medical-news-  As defense chemicals
2012.html#!/2012/08/medical-news-2012.html
 As human plant-based medicines,
Phytochemicals are sometimes flavorings and other uses
called secondary metabolites
© Project SOUND
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10. 3/11/2013
Phytochemicals  The distribution of phytochemicals within
plants is often tissue/organ specific
 These molecules tend to be concentrated
in outer cell layers of plant organs,
suggesting that they may indeed act as
deterrents to pathogens and pests.
 These compounds are of two types:
 Constitutive chemicals: made during
normal growth and development
(preformed antimicrobial compounds, or
“phytoanticipins”)
http://plantpathology.uark.edu/4844.htm  Induced chemicals: absent from healthy
plants, accumulating only in response to
pathogen attack or stress (‘phytoalexins’)
Whether a given compound has a defensive function is the
subject of much current interest & research
© Project SOUND
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11. 3/11/2013
Competition between plants: it’s a fact of life,
particularly in our mediterranean climate
 Light
 Water
 Soil nutrients
 Access to services of
beneficial organisms
Plants sometimes have to ‘fight
dirty’ to best their competitors:
allelopathy
http://primarybestsc.blogspot.com/2012/10/plants-competition.html
http://the-gist.org/2012/09/allelopathy-when-plants-attack/
© Project SOUND
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Southern CA Walnut – Juglans californica
http://biology.csusb.edu/PlantGuideFolder/JuglansCalif/JuglansCalifPage.htm
© Project SOUND
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13. 3/11/2013
S. CA Walnut: not for
every yard
 Proper location: consider
 Size: moderate for tree
http://biology.csusb.edu/PlantGuideFolder/JuglansCalif/JuglansCalifPage.htm  Light: full sun/part shade
 Soils: clay soils best
 Water regime:
 Tolerates seasonal flooding
 No or very occasional deep water
in summer (hot gardens)
 Allelopathy:
 Leaves produce chemicals toxic
to other plants
 Can’t grow plants under walnuts
http://www.phytoimages.siu.edu/imgs/paraman1/r/Juglandaceae_Juglans_
nigra_4178.html
© Project SOUND
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14. 3/11/2013
Allelopathy: one type of chemical warfare
 Term from allelon ("of each other“) and pathos ("to suffer“).
 Refers to the chemical inhibition of one species by another.
 Allelopathy has generally come to mean the deleterious effect
that one plant has on another through the production of
chemical retardants
 The "inhibitory" chemical is released into the environment where it
affects development and growth of neighboring plants.
 Process is often more complex:
 Allelopathic plants are also capable of stimulatory effects
 The chemical producing plant may also inhibit itself with the same
chemicals that inhibit its neighbors
 The process may involve other organisms [soil microbes]
© Project SOUND
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15. 3/11/2013
Plants release allelochemicals in several
different ways
 Above ground
 Leaves release volatiles
 Leaching from leaves
 Leaching from plant litter or
on decomposition
 Below ground
 From above-ground leachates
 Root exudates
 Decomposing roots
http://pubs.ext.vt.edu/430/430-021/430-021.html
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Naphthoquinones
 Often responsible for colored barks, root
barks and heartwoods
http://kremerpigments.com/shopus/index.php?cat=0104&lang=EN
 Example: Juglone (C.I. Natural Brown 7)
G&product=37300&sidFEE4B14F27014E7795A5F1BD0DD62743=
63e5300d98a56f6479a23d579380ca6a
 In leaves, roots, husks, and bark of plants in the
Juglandaceae family
 Is toxic or growth-stunting to many types of
plants and insect herbivores - inhibits key
enzymes needed for metabolic function.
 Awareness of walnut toxicity dates back at
least to Roman times
 Used as:
 an herbicide
 a dye for cloth and inks
 a coloring agent for foods and cosmetics (hair
dyes).
 Folk medicine – ground/extract green hulls
© Project SOUND
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17. 3/11/2013
Juglone is an effective toxin because it affects
basic processes required for life
 The active agent inhibiting growth of
other plants was suggested by Massey
in 1925; confirmed by Davis in 1928.
 Juglone disrupts oxygen and food use in
both plants and animals, a respiration
poison. Juglone is like cyanide in its
http://www.bgshoppingmall.com/Brand-Names/abbyson-
living.php
effect on people, animals, and plants
 Juglone is so toxic only minute amounts
can sicken, sedate, or kill people and
So how do walnut animals. The concentration difference
trees survive? of juglone between that needed for
sedation, and that causing death, is
small.
© Project SOUND
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18. 3/11/2013
The toxin is stored in a non-toxic form (so
it doesn’t harm the walnut tree)
 Juglone exists within wlanut tree cells in a
non-toxic form called hydrojuglone.
 Hydrojuglone is colorless and generally
nontoxic, but is immediately converted to
juglone by oxidation.
Upon continual contact with oxidative
http://www.biologie.uni-hamburg.de/b-online/ge20/02b.gif

conditions, or tissue drying, juglone is tied
up and decomposed.
 When you cut open a green walnut husk, it
quickly turns brown when exposed to air.
This is caused by the clear, non-toxic
hydrojuglone being quickly converted into
the toxic, dark brown juglone in the
presence of oxygen.
© Project SOUND
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19. 3/11/2013
Allelochemicals: many modes of action
 Allelopathic chemicals can be
present in any part of the plant -
leaves, flowers, roots, fruits, or
stems.
 They can also be found in the
surrounding soil.
 Target species are affected by
these toxins in many different ways:
 Inhibited shoot/root growth
 Inhibited nutrient uptake
 Altered symbiotic relationship
[mycorrhyzae] - destroying the
plant's usable source of a nutrient.
http://www.sustland.umn.edu/implement/images/trees_turf_4.gif
© Project SOUND
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20. 3/11/2013
Why do Juglans species make juglone? At
least part of the story involves seedlings
 Juglone in the husk protect the seed from being
eaten. The juglone also leaches into the
surrounding soil
 If juglone leaks back into a walnut root, it is
quickly made non-toxic again and stored.
 Annual plants, garden vegetables, fruit trees, and
some broad-leaf perennials can be severely
damaged when juglone is in the soil. These are a
seedling’s biggest competitors
http://www.hiltonpond.org/images/WalnutBlackS  Most grasses seem immune from juglone
problems.
eedling01.jpg
 Select mycorrhizal fungi and soil microbes have
been shown to be highly adapted to walnut tree
control zones and the presence of juglone.
© Project SOUND
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21. 3/11/2013
Other native trees/large shrubs with
allelopathic properties
 Oaks – Quercus spp.
 Cottonwoods – Populus spp.
 Manzanitas – Arctostaphylos spp.
 CA Sycamore – Platanus racemosa
 CA Bay Laurel - Umbellularia
californica
http://farm1.static.flickr.com/29/101896704_625b8ccece.jpg
 False Indigo - Amorpha fruticosa
 Eucalyptus
 Tree of Heaven
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22. 3/11/2013
Dealing with allelopathy in the garden
 Rake up leaves & other parts containing the chemicals(s)
 Leaves, twigs, fruit husks, and wood chips from walnut trees
should be well aged or completely composted before adding
to a garden or landscape, if at all
 Walnut stumps should be ground-down or removed from a
site
 Plant tolerant species under/near:
 Solanaceae, annuals are particularly susceptible
 Grasses are usually not
 Soil microorganisms ingest allelochemicals as energy sources,
and metabolic decomposition can render the chemicals non-
toxic to plants. When soils are well drained and aerated, a
healthy population of aerobic microorganisms can accelerate
this progress.
© Project SOUND
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23. 3/11/2013
But making Juglone is expensive: is
allelopathy the only explantion?
 Juglone precursors appear to be
translocated from older tissue to
younger tissue over time.
 The immediate precursors of
juglone are found in high
concentrations within buds,
flowers, fruit, and in the phloem
http://enhancedbc.tfrec.wsu.edu/CA_walnut.html (vascular system).
 Juglone is also effective for
protection from leaf, root and
stem pests, like insects, diseases,
nematodes, and grazing animals.
http://www.graftedwalnuts.co.uk/pest.ihtml
© Project SOUND
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24. 3/11/2013
Pros/cons of preformed defense
chemicals (or precursor forms of them)
 Positive
 Always ready
 Mechanism often involves basic
mechanisms – effective against a
wide range of living things
 Negative
 May not ever be needed – a waste of
energy & other resources
 Not specific – so may not work as well
against some threats
 May be deleterious to the plant itself
http://c0365781.cdn2.cloudfiles.rackspacecloud.com/datas/5598254/
original/799px-155mmMustardGasShells.jpg
© Project SOUND
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25. 3/11/2013
Southern Goldenrod – Solidago spectabilis var. confinis
http://www.jcsemple.uwaterloo.ca/goldenrod_figs.htm
© Project SOUND
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26. 3/11/2013
Other good native Goldenrods
Solidago californica Euthamia (Solidago) occidentalis
© Project SOUND
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27. 3/11/2013
The genus Solidago: the Goldenrods
 ~ 100 perennial species
 Most grow in meadows, pastures, along
roads & ditches in North America
 Unfairly blamed for hay fever in late
summer/fall - Ragweed (Ambrosia sp.),
blooming at the same time but wind-
pollinated, is the usual culprit.
 Easily recognized by their golden
flowering stalks with hundreds of small
flowers; plants & flowers make nice
yellow & green dyes.
 Their alternate leaves are linear to
CA Goldenrod - Solidago californica lanceolate. Their margins are usually
finely to sharply serrated.
Goldenrods have been used in
British gardens for > 200 years
© Project SOUND
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28. 3/11/2013
Southern Goldenrod is an herbaceous perennial
 Size:
 2-3 ft tall
 2+ ft wide, spreading
 Growth form:
 Stout looking herbaceous
perennial
 Fall/winter deciduous; dies
back to basal rosette
 Foliage:
 Leaves lance-shaped – mostly
basal
 Leaves fleshy, bright to pale
green
 Roots: spreads via rhizomes
© Project SOUND
© 2003 Christopher L. Christie
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29. 3/11/2013
The genus Solidago: the Goldenrods
 Propagation by wind-
disseminated seed or
underground rhizomes (form
patches that are vegetative
clones of a single plant).
 Goldenrod is a companion plant,
CA Goldenrod - Solidago californica
playing host to beneficial
insects, repelling some pests
 Goldenrods are important
habitat plants for a wide range
of native insects, butterflies,
birds, etc.
© Project SOUND
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30. 3/11/2013
Outside of their native range, Goldenrods
can be invasive. Why?
© Project SOUND
http://www.calflora.net/bloomingplants/southerngoldenrod.html
http://www.calflora.net/bloomingplants/southerngoldenrod.html
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31. 3/11/2013
Teasing out whether the effect is due to allelopathy:
can be difficult  Competing processes: competition for
 Light
 Water
 Nutrients
 Associated animal species may be the
culprit:
 Pollinators, mycorrhyzae, other
beneficial species
 Above or below-ground pests – Solidago
may be tolerant
 Vast number of chemicals produced;
many not toxic (at least to other plants)
 Nature of the chemicals themselves:
highly changeable (oxygen; pH; exposure
to other chemicals)
© 2003 Christopher L. Christie © Project SOUND
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32. 3/11/2013
Bioassays often used to test for allelopathy
http://www.biosci.ohio-state.edu/~plantbio/osu_pcmb/pcmb_lab_resources/images/pcmb300lamb/allelopathyExperiment.jpg
 Example: testing the effects of plant tissue extracts (or specific
chemicals) on the germination of seeds.
 Issues in relating laboratory bioassays to allelopathic
interactions in the field; allelopathy in the laboratory is not
always demonstrated in the field – and vice versa
http://plantecology.dbs.umt.edu/People/collaborators.html
© Project SOUND
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33. 3/11/2013
Why are U.S. Goldenrods so invasive in
China? Could it be due to allelpathy?
 Extracts were made from 12.5 g of dried
leaf tissue placed in 500 ml of distilled
water.
 Dilutions of each extract, ranging from
0% to 100% in 10% increments were
made.
 Filter paper was placed in 90 mm petri
plates with 20 seeds of the target
species (lettuce & radish).
 Five trials were run for each dilution for
each goldenrod species tested.
http://posieinthevase.blogspot.com/
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34. 3/11/2013
The answer is not exactly straightforward
 Solidgo canadensis does influence soil
levels of possible allelochemicals
(total phenolics, total flavones and
total saponins)
 The chemical content and possible
allelopathic effects were greater in
S. canadensis from China than
those from the USA as demonstrated
in a field survey and a common garden
http://www.sciencedirect.com/science/article/pii/S0929139311000849 experiment.
 Suggests that S. canadensis has
But is the effect direct? evolved to be more competitive – and
possibly more allelopathic - in the
introduced range
 Allelopathy might significantly
increase competitiveness for this
invasive species. © Project SOUND
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35. 3/11/2013
Plants have complex relationships with
other living things
http://www.sciencedirect.com/science/article/pii/S1360138510001007
© Project SOUND
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36. 3/11/2013
Roots and the rhizosphere: life within the soil
Beneficial effect
of mycorrhyzae
http://ars.els-cdn.com/content/image/1-s2.0-S1360138512000799-gr2.jpg
© Project SOUND
http://www.cottoncrc.org.au/industry/Tools/Symptoms_Identification_Tool/Cotton_Symptoms/Allelopathy
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37. 3/11/2013
Goldenrods brought ‘novel weapons’ with them
 S. canadensis altered the indigenous
mycorrhizal fungal spore composition
and reduced the mycorrhizal
colonization of native plants one year
after invasion.
 The alien Goldenrod inhibited the
colonization of native species and
changed the indigenous mycorrhizal
fungi by exuding allelochemicals.
 Experimental results suggest that
http://openi.nlm.nih.gov/detailedresult.php?img=2972720_pone.0015418.g001&query=the
&fields=all&favor=none&it=none&sub=none&uniq=0&sp=none&req=4&simCollection=305
invasive S. canadensis may acquire
8081_1471-5945-11-5-6&npos=74&prt=3
spreading advantage in non-native
habitat by using “novel weapons” to
inhibit not only local plants but also
soilborne pathogens and beneficial
microbes.
© Project SOUND
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38. 3/11/2013
A novel, non-native plant species (like Goldenrod)
can have many effects on the environment
http://www.sciencedirect.com/science/article/pii/S016953471000145X © Project SOUND
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39. 3/11/2013
You may have noticed that the Sunflower
family is pretty successful
 The Sunflower family
(Asteraceae) is one of the
most diverse families in
California.
 Largest plant family
worldwide: contains ~ 1550
genera and 24,000 species.
 Almost 200 pages of the
Jepson Manual are dedicated
http://www.wildflowers-and-weeds.com/Plant_Families/Asteraceae_pics/Asteraceae.jpg
to describing the California
species alone.
Why are they so successful?
© Project SOUND
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40. 3/11/2013
Possible reasons for Sunflower success
 Ability to adapt well to variety
of environments
 Plasticity: changes in phenotype
 Ability to evolve quickly – change
in the genes in the population
 Make lots of seeds
 Work well with wide range of
pollinators and other beneficial
species
 ?? Good defenses
© Project SOUND
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41. 3/11/2013
What types of invaders/competitors do
plants need to worry about?
 Other plants
(compete for water,
light, nutrients)
 Large herbivores
 Insect herbivores
 Other herbivores:
mollusks
 Pathogens
 Fungal
http://www.sciencedirect.com/science/article/pii/S1360138509003008
 Bacterial
 Viral
© Project SOUND
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42. 3/11/2013
Young leaves and other tissues are
attractive food
© Project SOUND
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43. 3/11/2013
Why do plants make the chemicals found
in ‘essential oils’?
 A wide range of reasons, many
related to communication:
 To attract pollinators – or the
spreaders of seed (usually in
flowers, fruits)
 To repel herbivores – insect or
other; either cue or toxin
 As breakdown products from
compounds used for other purposes
 As protection against fungi, bacteria
and viruses
 To prevent other plants from
growing too close ?
 To communicate with other plants –
via soil water or air
© Project SOUND
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44. 3/11/2013
The ‘Double-whammy’ of injury
http://ericwongmma.com/wp-
content/uploads/2013/01/double-
whammy.jpg  Tissue damage (from physical
injury or herbivory)
 Vascular tissue: must seal off
quickly, then re-grow or re-attach
if possible
 Water – Xylem tissue
 Nutrients + other - Phloem tissue
 Support tissue
 Other
http://www.tantebazar.com/gardening_histology_of_plant_part_2.php
 Secondary infection
 Bacterial
 Fungal
 Viral
http://ipm.ncsu.edu/corn/diseases/cornfg18.gif © Project SOUND
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45. 3/11/2013
Insects are known to be selective in their
use of plants in the sunflower family
http://ipmworld.umn.edu/chapters/charlet2.htm
Long-horned Beetle
Sunflower Bud Moth
This suggests that Asteraceae may selectively deter some pest species
© Project SOUND
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46. 3/11/2013
Certain plant compounds are effective
against insect herbivores
http://michellebiology.blogspot.com/2012/02/54-pesticide-and-biological-control.html
 The most important of these are alkaloids, terpenoids,
steroids, phenols, saponins and tannins
 These may be an alternative source of insect control agents
© Project SOUND
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47. 3/11/2013
The most cost effective strategy is often
to prevent/limit herbivory
 Has a pleasant odor similar to
pennyroyal, peppermint and
camphor.
 Is used in flavoring agents, in
perfumery, and in
aromatherapy
Pulegone
 Insect repellant; less toxic to
animals/humans than other
Plants in both the Sunflower insect repellants
and Mint families make a range
of chemicals to prevent/limit
herbivory
© Project SOUND
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48. 3/11/2013
Mint family insecticidals: mostly terpenoids
 Most common : monoterpenes (1,8-cineole,
thujone, camphor, pulegone, menthone, others)
 Plant-derived insecticides may represent
alternative pest control strategies.
 They may degrade more rapidly than the
synthetic insecticides
 May be more specific in their action
 Have no genotoxicity.
 Mint oil is already used as an environmentally-
friendly insecticide for some common pests like
wasps, hornets, ants and cockroaches
 Mints also repel some birds & other large
herbivores – terpenoid’s smells repel
© Project SOUND
http://www.safesolutionsinc.com/TweetMint_Gallon.jpg
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49. 3/11/2013
Diterpenes: another class of bioactive
terpenoids
 They have 20 carbon atoms
 Produced by plants and fungi; often play
active role as hormones (Gibberelins)
 Found in resins, gummy exudates, and in
the resinous high-boiling fractions
remaining after distillation of essential
http://ars.els-cdn.com/content/image/1-s2.0-
S0367326X02001703-gr1.gif
oils.
 Diterpenes display a broad range of
activities against insects
 Important defense chemicals in
Asteraceae, Salvia, many others
monoterpenes
© Project SOUND
http://www.cyberlipid.org/images/pict295.gif
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50. 3/11/2013
How do plant insecticidal chemicals work?
 Feeding deterrants:
 Render plants unattractive or unpalatable;
 Usually small chemicals; may be aromatic
 Often bitter or strong tasting/smelling
 Examples: alkeloids, terpenopids;
http://www.gov.mb.ca/agriculture/crops/ins
 Direct toxicity:
 Kill insects outright; or stun them
ects/images/fae02s00a.jpg
significantly so that they are eaten by their
predators
 Usually function as neurotoxins
 Examples:
 Other, more subtle methods:
© Project SOUND
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51. 3/11/2013
How do plant insecticidal chemicals work?
A few more subtle means
 Modifying plant food absorption
 Modify either the food itself, the gut wall or gut flora
 Often larger size
 Example: Tannins – make food undigestable
 Disrupting the endocrinologic balance of insects
 Affects reproduction
 Acting as insect growth regulators, disrupting the normal
process of morphogenesis
 May ultimately kill
 Usually affects reproduction
 Behaviour modifying agents
 Usually influence the feeding and ovipositing (egg-laying) behavior
of insects
© Project SOUND
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52. 3/11/2013
California/Big Gum Plant
Grindelia camporum var. bracteosa
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53. 3/11/2013
CA Gum Plant
 Erect herbaceous perennial to 4
ft tall by 4 ft wide
 Grows in clay or sandy soil:
 Dry stream banks, washes
 Rocky fields & plains
 Sandy or alkali bottomlands
 Along road sides
 Grows where it gets full sun
 Is stress deciduous – looses
leaves during dry periods
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Asteraceae species do much to protect
their young leaves & flowers
© Project SOUND
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Gumplants make an interesting array of chemicals
 Active compounds: resin flavanoids
and diterpenes of the grindelane type.
 The resin produced in multicellular
glands on the surfaces of stems,
leaves, and involucres - density of
resin glands highest on the immature
involucre bracts and lowest on the
stems.
 The resin is composed of grindelic
acid and several of its derivatives.
These labdane diterpenes are similar
to the resin acids that constitute
rosin, a principal product of the naval
stores industry
© Project SOUND
http://www.ag.arizona.edu/~spmcl/Research/newcrops.htm
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Protecting developing leaves and flowers
 Grindelia species are used as food plants
by the larvae of some Lepidoptera species
including Flower Moths, other herbivores
 Grindelane diterpenoids make up most of
the resin (to 20% of the dry weight).
 Grindelic acid, camporic acid,
 17-carboxygrindelic acid
 many other diterpenoids
 The diterpenoids appear to have insect
repellant/insecticidal & antibiotic activity
 Used as a traditional medicine (until 1960)
 wide range of ailments: asthma, bronchitis;
Balsamic scent – fairly strong
antispasmodic , urinary tract disinfectant;
topical preparations to soothe burns, insect
bites, skin rashes, poison ivy rash.
© Project SOUND
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57. 3/11/2013
Labdane terpinoids: typical preformed
compounds affecting a wide range of pests
 Stored where likely to be needed
 Resin ducts of trichomes of leaves
 In special plastids in epidermal or other near-
surface cells
 A variety of biological activities:
 Antibacterial, antifungal, antiprotozoal
Found in many plant  Anti-inflammatory activities and modulation of
parts (above/below- immune cell functions – may induce long-term
ground) immunity
 Significant effects on basic cell processes:
 Interfere with biochemical pathways of cell
death and the cell cycle phases
 May explain why they affect wide range of cell
types in pests (insects, microbes) and in humans
© Project SOUND
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58. 3/11/2013
Have you ever noticed how birds know
when the fruits are ripe?
http://www.gardenguides.com/633-barren-bushes-treat-
hungry-birds.html
© Project SOUND
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59. 3/11/2013
Many fruit-berry plants use critters to
spread their seeds
 Berries attract the critter
 Critter eats the fruit –yum!
 Critter moves around while
seeds pass through the
digestive tract
 Seed are deposited – with
a load of fertilizer – in a
new place away from the
parent plant
Cedar Waxwing gobbling up Toyon fruits
 How do the birds know the
fruits are ripe?
http://www.ibabuzz.com/garybogue/2009/04/15/cedar-waxwings-they-will-eat-no-toyon-berry-
before-its-time/ © Project SOUND
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60. 3/11/2013
Toyon/California Christmas Berry –
Heteromeles arbutifolia
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Toyon in nature
 Formerly common in the
South Bay:
 Semi-dry slopes
 Back dune areas (old sand)/
coastal prairie
 Canyons sides
 Likes some seasonal moisture
 Found on sandy or rocky soils
 Strong branching root
system
 Re-sprouts after a fire
 This is the “red-berried
shrub” that you see on native
hillsides everywhere in
winter
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But it’s the berries that made it famous
 Formed in late summer
 Turn bright red in Nov.
 Beloved by birds – this is a
great plant to attract
 Doves
 Cedar Waxwings
 Songbirds
 Squirrels also like them
 Makes nice holiday
decorations
 Berries toxic if many are
eaten (particularly the unripe,
uncooked berries)
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63. 3/11/2013
Rose’s dirty little secret…poison
 The highly cyanogenic nature of
rosaceous stone fruits (e.g.
almonds, peaches, cherries) has
long been known.
 The fleshy portions of the ripe
fruits are basically innocuous – so
we eat them
 The seeds, which accumulate the
cyanogenic disaccharide (R)-
amygdalin, have been responsible
for numerous cases of acute
cyanide poisoning of humans and
domesticated and wild animals
http://barefootintheorchard.blogspot.com/2011/07/fridays-photos-stone-fruit.html © Project SOUND
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Yikes, cyanide?
 Cyanogenic glycosides are hydrolyzed by
enzymes (b-glycosidases) with the
release of hydrogen cyanide.
 Cyanide is one of the quickest acting
poisons – stops production of energy, so
heart, nervous system, breathing stop
 Why aren’t the plants killed?
 The glycosides are stored in vacuoles
within plant cells, while the hydrolytic
http://www.ag.ndsu.edu/publications/landing-
pages/livestock/cyanide-poisoning-v-1150
enzymes are found in the cytosol – fine
until something injures the cells
 Plants also have a way to produce the
energy molecules (ATP) even when
exposed to cyanide
© Project SOUND
http://leavingbio.net/cell%20structure_files/Cell%20Structure_files/image007.jpg
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Plants use several strategies to protect
themselves against their own toxins
 Enzymes to quickly break down the toxins
 Other ways around the toxic effects
 Sequestration of toxic chemicals – lock away in a safe place
 Storage as non-toxic precursor chemicals – that can be
readily formed into toxins as needed
 Compartmentalization
 Storing precursors and enzymes in separate compartments –
only released with cell/tissue damage
 Storing precursors and enzymes in separate tissues -
© Project SOUND
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66. 3/11/2013
Heteromeles – just a rose by another name?
 The cyanogenic glycoside content of Toyon -
as well as its resultant toxicity to insects and
other herbivores - is well described.
 The cyanogenic potential is highest in the
newly developing leaves.
 The cyanic glycosides in the pulp of immature
fruits protect them from premature bird
predation
 During the long seed maturation process,
cyanogenic glucosides are gradually shifted
from pulp to seed, while pulp carbohydrates
increase and fruits turn from green to red.
http://curls-eyelashes.blogspot.com/2012/12/why-coat-apple-fruits.html
 The birds read the cues and eat the fruit
Toyon is the ‘pome’ branch of the  Subsequent seed predation is prevented by
Rose Family along with quince, pear, the localization of cyanogenic glycosides in
apple hawthorn, pyracantha, the seeds. It can be used (as needed) or
cotoneaster, pomegranate, and others converted to other Nitrogen compounds.
© Project SOUND
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Cyanide: some herbivores more vulnerable
 Substantial evidence that cyanogenic
glycosides are primarily involved in
defence against generalist herbivores
including mammals, insects and
molluscs
 Rumen microorganisms produce the
hydrolysis enzymes. Ruminants are
therefore more susceptible to the
http://www.urbanoutdoorskills.com/NEWS/2011_ToyonJam.jpg
toxic effects of cyanide
 Most larger animals can detoxify in
limited amounts
 Heat releases HCN – cooking and
dyeing
http://sunnysavagedesigns.com/wp-content/uploads/2012/11/medicinal-
clothing-sunny-savage-designs-natural-dye-toyon-hollywood-bioregional- © Project SOUND
slow-fashion-eco.jpg
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68. 3/11/2013
Leaves of some Chaparral plants are
indigestible as well as water-conserving
 Most woody chaparral plants allocate
significant energy resources to forming
chemical compounds that deter herbivores or
pathogens from feeding.
 One of the most important such compounds is
tannin. Up to twenty percent of the dry
‘What doesn’t kill weight of leaf tissues in some shrubs may be
me will starve me’ composed of tannins.
 Oak, manzanita and toyon have tannin-rich
leaf tissues.
 Mechanism of action: binds proteins to form
non-biodegradable products – that’s why the
leaves don’t degrade very quickly
© Project SOUND
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69. 3/11/2013
Silver Bush Lupine – Lupinus albifrons
© Project SOUND
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Flowers that glow in
the silvery light
 Blooms:
 Spring; usually Mar-Apr or even
May our area
 Long bloom season
 Flowers:
 Typical lupine/pea shape
 On stalks above the foliage
 Often appear almost an
iridescent blue/purple – in part
due to contrast with silvery
foliage
 Banner spot turns from white to
pink when pollinated
 Seeds: pods explode (dehisc)
flinging the seeds from parent plant
© Project SOUND
http://www.manhattanbeachbotanicalgarden.org/springbloomerspage2manhattanbeachbotanical
garden.html
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71. 3/11/2013
Silvery Dune Lupine makes a
nice mid-size shrub
 Nice as a smaller foundation
plant
 Floral fragrance – plant where
http://farm4.static.flickr.com/3175/2673277265_678df36ea6.jpg
you can enjoy
 Quite hardy – fine for parking
strips, roadways
 Nice addition to rock garden
 Wonderful for the ‘evening
garden’ with its silvery foliage
Not the best of plants for eating
http://norenes5percent.blogspot.com/2006_03_01_archive.html
© Project SOUND
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72. 3/11/2013
Many herbivores avoid Silver Bush lupine
 Plant produces bitter-tasting toxins – the
nitrogen-containing Quinolizidine alkaloids
 These toxins can negatively affect livestock,
causing birth defects and decreasing weight
http://www.nps.gov/goga/images/20
080328170300.jpg
especially in young, unexperienced cattle,
sheep, horses
 Deer and rabbits avoid it
 Deter insects leaf herbivores: aphids,
beetles, thrips
 The larva of the federally-endangered
mission blue butterfly feed on Lupinus
albifrons, becoming toxic and giving it a
bitter taste to deter predators [similar to
Monarch & Milkweeds].
© Project SOUND
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73. 3/11/2013
Like Toyon, Lupines also protect their
seeds with chemical poisons
 Aklaoids :
 found in a wide variety of plants, animals, and
fungi
 Many have medicinal and toxic properties.
 Quinolizidine alkaloids (QAs) are known as
lupine alkaloids because they mainly occur in
lupinus species. Example: lupinine
 Produced in green tissues; transported via
phloem, stored in all organs of the plant, but
particularly in reproductive organs/ seeds
 Defense against pathogens and predators
© Project SOUND
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74. 3/11/2013
Quinolizidine alkaloids (QAs) protect
lupines throughout life
 Available pre-formed in seeds –
protect seeds from insect herbivory
 Released into the rhizosphere at
germination – protect roots of young
seedlings from fungal and bacterial
pathogens
 Induced by biotic stresses in older
plants – mobilized in times/places
where needed
http://www.unine.ch/bota/lamun/ang/pictures/projects/logoface.jpg © Project SOUND
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© Project SOUND
http://urbanext.illinois.edu/soil/SoilBiology/images/A-3.jpg
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Wavy-leaf Soap Plant - Chlorogalum
pomeridianum var. pomeridianum
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77. 3/11/2013
Wavy-leaf Soap Plant - Chlorogalum
pomeridianum var. pomeridianum
 West coast from S. OR to
N. Baja
 In southern CA commonly
found:
 Grasslands
 Open hillsides
 Sheltered places in coastal
sage scrub, chaparral
 Member of the Lily family
http://www.swsbm.com/Maps/Chlorogalum.gif
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The Lily Family (Liliaceae)
http://www.wcosf.org/php/d1f.php?sci_name=Chlorogalum%20pomeridianuml
 Strap-like leaves with parallel veins
(grass-like)
 Flowers in ‘3’s
 Bulb-forming
 Includes many edible native plants (onions,
http://www.vernalpools.org/Mather/list/pages/chlpom.htm wild hyacinths (brodeas), Mariposa Lilys)
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Soap Plant
requirements
 Light: full sun to
part-shade
 Soils: any local
(well-drained best)
 Water:
 tolerates average
to low watering
http://www.pacificbulbsociety.org/pbswiki/index.php/Chlorogalum
 Requires dry period
in late summer/fall
 Nutrients:
benefits from
organic mulch
http://plants.montara.com/ListPages/FamPages/Lilia2.html
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80. 3/11/2013
The Amole bulb:  For the plant
 Storage organ for plant
useful organ, indeed  Reproductive organ for plant
 Potential food source for animals
 Many uses for humans:
 Edible: must slow bake to remove
bitter saponins
http://plants.montara.com/ListPages/FamPages/Lilia2.html  Makes good shampoo/soap; can
even dry for stored soap
 Medicinal: for cramps and
rheumatism; an antiseptic rub for
treating wounds, infections and sores;
and an internal remedy for treating
stomachache and gas.
 To stun fish
 Hairy covering makes good brush
Saponins are responsible for  Baked ‘juice’ used as glue
some of these uses
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81. 3/11/2013
 High-molecular-weight compounds with
a fat-soluble nucleus (either a steroid
Saponins: a group of or triterpenoid structure) and one or
related chemicals more side chains of water-soluble
sugars
 Despite their fairly large structural
diversity these compounds share some
unique biological properties:
 The ability to lyse cells (erythrocytes)
 To ability foam when agitated in water
 Triterpene saponins are more widely
Saponins are glucosides (or
glycosides): plant compounds
distributed in nature, primarily in
containing glucose (or another dicots; steroidal saponins are less
sugar) combined with other non- common and usually found in monocots,
sugar molecules. particularly among members of such
families as Liliaceae, Dioscoreaceae,
Agavaceae, Alliums
© Project SOUND
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82. 3/11/2013
Saponins: why do they foam?
 The ability of a saponin to foam is
caused by the combination of the non-
polar sapogenin and the water soluble
side chain present on the molecule.
 The foams tend to be stable and have
been used in fire extinguishers as the
http://www.instructables.com/id/A-Homemade-
Organic-Herbal-Shampoo/step6/Blend/
foaming agent.
Yucca root soap  They are also used to produce foam in
beer and are responsible for the natural
foam in root beer.
 They have been used as the foaming
agent in toothpaste and are employed by
local people where the plants occur as a
shampoo and laundry detergent.
http://www.indianweaving.com/wool.html © Project SOUND
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