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Garden warfare - How Plants Protect Themselves


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This lecture was given in March, 2013 as part of the California native plant gardening series ‘Out of the Wilds and Into Your Garden’

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Garden warfare - How Plants Protect Themselves

  1. 1. 3/11/2013 Out of the Wilds and Into Your GardenGardening with California Native Plants in Western L.A. County Project SOUND – 2013 (our 9th year) © Project SOUND 1
  2. 2. 3/11/2013Warfare in the Gardenhow 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 2
  3. 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 3
  4. 4. 3/11/2013Plants are primary producers Photosynthesis: stored energy, other (biomass)  That means they are ‘food’ to many organisms © Project SOUND 4
  5. 5. 3/11/2013But plants aren’t merely generous benefactors or faithful servants…. © Project SOUND 5
  6. 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 thingsCA Goldenrod - Solidago californica © Project SOUND 6
  7. 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  They often behave more like plant warriors than like shrinking violets © Project SOUND 7
  8. 8. 3/11/2013 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 8
  9. 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:  As defense chemicals2012.html#!/2012/08/medical-news-2012.html  As human plant-based medicines,Phytochemicals are sometimes flavorings and other usescalled secondary metabolites © Project SOUND 9
  10. 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”)  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 thesubject of much current interest & research © Project SOUND 10
  11. 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 © Project SOUND 11
  12. 12. 3/11/2013 Southern CA Walnut – Juglans californica © Project SOUND 12
  13. 13. 3/11/2013 S. CA Walnut: not for every yard  Proper location: consider  Size: moderate for tree  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 © Project SOUND 13
  14. 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 14
  15. 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 © Project SOUND 15
  16. 16. 3/11/2013 Naphthoquinones  Often responsible for colored barks, root barks and heartwoods  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 16
  17. 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 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 17
  18. 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  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 18
  19. 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 plants usable source of a nutrient. © Project SOUND 19
  20. 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  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 20
  21. 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  False Indigo - Amorpha fruticosa  Eucalyptus  Tree of Heaven © Project SOUND 21
  22. 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 22
  23. 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 (vascular system).  Juglone is also effective for protection from leaf, root and stem pests, like insects, diseases, nematodes, and grazing animals. © Project SOUND 23
  24. 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 © Project SOUND 24
  25. 25. 3/11/2013Southern Goldenrod – Solidago spectabilis var. confinis © Project SOUND 25
  26. 26. 3/11/2013 Other good native GoldenrodsSolidago californica Euthamia (Solidago) occidentalis © Project SOUND 26
  27. 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 toCA Goldenrod - Solidago californica lanceolate. Their margins are usually finely to sharply serrated.Goldenrods have been used inBritish gardens for > 200 years © Project SOUND 27
  28. 28. 3/11/2013Southern 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 28
  29. 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 29
  30. 30. 3/11/2013 Outside of their native range, Goldenrods can be invasive. Why? © Project SOUND 30
  31. 31. 3/11/2013Teasing 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 31
  32. 32. 3/11/2013Bioassays often used to test for allelopathy 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 © Project SOUND 32
  33. 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. © Project SOUND 33
  34. 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 experiment.  Suggests that S. canadensis hasBut 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 34
  35. 35. 3/11/2013 Plants have complex relationships with other living things © Project SOUND 35
  36. 36. 3/11/2013Roots and the rhizosphere: life within the soilBeneficial effectof mycorrhyzae © Project SOUND 36
  37. 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 invasive S. canadensis may acquire8081_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 37
  38. 38. 3/11/2013A novel, non-native plant species (like Goldenrod) can have many effects on the environment © Project SOUND 38
  39. 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 to describing the California species alone. Why are they so successful? © Project SOUND 39
  40. 40. 3/11/2013Possible 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 40
  41. 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  Bacterial  Viral © Project SOUND 41
  42. 42. 3/11/2013Young leaves and other tissues are attractive food © Project SOUND 42
  43. 43. 3/11/2013Why 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 43
  44. 44. 3/11/2013 The ‘Double-whammy’ of injury 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  Secondary infection  Bacterial  Fungal  Viral © Project SOUND 44
  45. 45. 3/11/2013 Insects are known to be selective in their use of plants in the sunflower family Long-horned Beetle Sunflower Bud MothThis suggests that Asteraceae may selectively deter some pest species © Project SOUND 45
  46. 46. 3/11/2013 Certain plant compounds are effective against insect herbivores 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 46
  47. 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 otherPlants in both the Sunflower insect repellantsand Mint families make a rangeof chemicals to prevent/limitherbivory © Project SOUND 47
  48. 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 48
  49. 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 S0367326X02001703-gr1.gif oils.  Diterpenes display a broad range of activities against insects  Important defense chemicals in Asteraceae, Salvia, many others monoterpenes © Project SOUND 49
  50. 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;  Direct toxicity:  Kill insects outright; or stun themects/images/fae02s00a.jpg significantly so that they are eaten by their predators  Usually function as neurotoxins  Examples:  Other, more subtle methods: © Project SOUND 50
  51. 51. 3/11/2013How 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 51
  52. 52. 3/11/2013 California/Big Gum PlantGrindelia camporum var. bracteosa 52
  53. 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 53
  54. 54. 3/11/2013Asteraceae species do much to protect their young leaves & flowers © Project SOUND 54
  55. 55. 3/11/2013Gumplants 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 55
  56. 56. 3/11/2013 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 56
  57. 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, antiprotozoalFound in many plant  Anti-inflammatory activities and modulation ofparts (above/below- immune cell functions – may induce long-termground) 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 57
  58. 58. 3/11/2013Have you ever noticed how birds know when the fruits are ripe? hungry-birds.html © Project SOUND 58
  59. 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? © Project SOUND 59
  60. 60. 3/11/2013Toyon/California Christmas Berry – Heteromeles arbutifolia 60
  61. 61. 3/11/2013 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 61
  62. 62. 3/11/2013But 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) 62
  63. 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 © Project SOUND 63
  64. 64. 3/11/2013 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 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 64
  65. 65. 3/11/2013 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 65
  66. 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.  The birds read the cues and eat the fruitToyon is the ‘pome’ branch of the  Subsequent seed predation is prevented byRose Family along with quince, pear, the localization of cyanogenic glycosides inapple hawthorn, pyracantha, the seeds. It can be used (as needed) orcotoneaster, pomegranate, and others converted to other Nitrogen compounds. © Project SOUND 66
  67. 67. 3/11/2013 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 toxic effects of cyanide  Most larger animals can detoxify in limited amounts  Heat releases HCN – cooking and dyeing clothing-sunny-savage-designs-natural-dye-toyon-hollywood-bioregional- © Project SOUND slow-fashion-eco.jpg 67
  68. 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 beme 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 68
  69. 69. 3/11/2013Silver Bush Lupine – Lupinus albifrons © Project SOUND 69
  70. 70. 3/11/2013 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 70
  71. 71. 3/11/2013 Silvery Dune Lupine makes a nice mid-size shrub  Nice as a smaller foundation plant  Floral fragrance – plant where 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 © Project SOUND 71
  72. 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 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 72
  73. 73. 3/11/2013Like 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 73
  74. 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 © Project SOUND 74
  75. 75. 3/11/2013 © Project SOUND 75
  76. 76. 3/11/2013Wavy-leaf Soap Plant - Chlorogalum pomeridianum var. pomeridianum 76
  77. 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 77
  78. 78. 3/11/2013 The Lily Family (Liliaceae)  Strap-like leaves with parallel veins (grass-like)  Flowers in ‘3’s  Bulb-forming  Includes many edible native plants (onions, wild hyacinths (brodeas), Mariposa Lilys) 78
  79. 79. 3/11/2013 Soap Plant requirements  Light: full sun to part-shade  Soils: any local (well-drained best)  Water:  tolerates average to low watering  Requires dry period in late summer/fall  Nutrients: benefits from organic mulch 79
  80. 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  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 80
  81. 81. 3/11/2013  High-molecular-weight compounds with a fat-soluble nucleus (either a steroidSaponins: 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 widelySaponins are glucosides (orglycosides): plant compounds distributed in nature, primarily incontaining glucose (or another dicots; steroidal saponins are lesssugar) 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 81