Plant Plant Reproduction Reproduction and Responsesand ResponsesBy: Diana Boyle, Jordan Capelle, Ross Dairiki, Erika By: Diana Boyle, Jordan Capelle, Ross Dairiki, Erika KeerKeer

General Info.General Info.

FertilizationFertilization=Fusion of =Fusion of gametesgametes

2 reproductive 2 reproductive structures: FLOWERS & structures: FLOWERS & FRUITSFRUITS

FlowersFlowers

FlowersFlowers=Reproductive shoots of angiosperm =Reproductive shoots of angiosperm sporophytessporophytes

- - Complete FlowersComplete Flowers have 4 basic floral have 4 basic floral organs (sepals, petals, stamens, organs (sepals, petals, stamens,

carpels)carpels)

- - Incomplete FlowersIncomplete Flowers lack 4 basic organs lack 4 basic organs (Example: Grass Flowers)(Example: Grass Flowers)

- - Some flowers are sterile--lack stamens and Some flowers are sterile--lack stamens and carpelscarpels

- - Others are unisexual--lack either stamens Others are unisexual--lack either stamens or carpelsor carpels

-- Inflorescence Inflorescence=Cluster of flowers =Cluster of flowers

Diagram of a flower (left) and fertilization (right)

GametophytesGametophytes MALEMALE FEMALEFEMALE

Mechanism of Mechanism of FertilizationFertilization

PollinationPollination=Transfer of pollen from an anther to a =Transfer of pollen from an anther to a stigmastigma

- Made possible by wind (random seed dispersal), water, - Made possible by wind (random seed dispersal), water, or animals (insects, birds, bats)or animals (insects, birds, bats)

CoevolutionCoevolution=Joint evolution of two interacting =Joint evolution of two interacting species, each in response to selection imposed by species, each in response to selection imposed by the otherthe other

- - Many species of flowering plants have Many species of flowering plants have coevolved with coevolved with specific specific pollinators pollinators

Double Double FertilizationFertilization

The union of 2 The union of 2 sperm cells with sperm cells with

different nuclei of different nuclei of the female the female

gametophytegametophyte

Seed Structure and Seed Structure and FunctionFunction

Diagram of Seed

Fruit Structure & Fruit Structure & FunctionFunction

FruitFruit=developed =developed from flower ovary from flower ovary Protect enclosed Protect enclosed

seedsseeds Aid in dispersalAid in dispersal

Animals eat fruit and Animals eat fruit and poop out seeds in poop out seeds in new locationnew location

Fertilization triggers Fertilization triggers hormonal changes hormonal changes that begin ovary that begin ovary transformationtransformation

Developmental Origin Developmental Origin of Fruitsof Fruits

Asexual ReproductionAsexual Reproduction

Can be sustained byCan be sustained by meristems meristems=regions of =regions of undifferentiated, dividing cellsundifferentiated, dividing cells

Parenchyma cells throughout plant divide and Parenchyma cells throughout plant divide and differentiate into more specialized types of differentiate into more specialized types of cells (regenerate lost parts)cells (regenerate lost parts) FragmentationFragmentation=separation of parent plant =separation of parent plant

into parts that develop into whole plantsinto parts that develop into whole plants ApomixisApomixis=asexual production of seeds=asexual production of seeds

Benefits of Benefits of Reproductive MethodsReproductive Methods

ASEXUALASEXUAL

No need No need for pollinatorfor pollinator

Allows plant to pass Allows plant to pass exact copyexact copy of genes (good of genes (good if environment is stable)if environment is stable)

Offspring Offspring generally generally stronger stronger than sexually than sexually

produced offspring produced offspring (though germination is still (though germination is still

very precariousvery precarious

SEXUALSEXUAL

Better against Better against unstable unstable environments environments (pathogens, (pathogens, other fluctuation) because other fluctuation) because

it generates variationit generates variation

Dispersal Dispersal of offspring to of offspring to more distant locationsmore distant locations

Seed dormancy puts Seed dormancy puts growth growth on hold on hold until until

environmental conditions environmental conditions become more favorablebecome more favorable

This music video includes some general information about plant reproduction/responses to provide a break from slides!

Enjoy

Mechanisms to Prevent Mechanisms to Prevent Self-FertilizationSelf-Fertilization

Self-fertilization Self-fertilization increases genetic increases genetic variety by ensuring variety by ensuring sperm and egg from sperm and egg from differentdifferent parents parents

Self-incompatibilitySelf-incompatibility= = Ability of a plant to Ability of a plant to rejectreject its own pollen its own pollen and sometimes the and sometimes the pollen of closely related pollen of closely related individualsindividuals

Dioecious Dioecious speciesspecies=Plants can’t =Plants can’t self-fertilize because self-fertilize because different individuals different individuals have eitherhave either staminate staminate flowers (no carpels) orflowers (no carpels) or carpellate carpellate flowers (no flowers (no stamens); other plants stamens); other plants have functional carpel have functional carpel and stamens, but and stamens, but mature at diff. times or mature at diff. times or have unfavorable have unfavorable orientationorientation

Human ManipulationHuman Manipulation

Clones from cuttingClones from cutting: most houseplants, woody : most houseplants, woody ornamentals, and orchard treesornamentals, and orchard trees

GraftingGrafting: makes it possible to combine the best : makes it possible to combine the best qualities of different species or varieties into 1 qualities of different species or varieties into 1 plantplant ““Host” plant=Host” plant=stockstock, grafted part=, grafted part=scionscion

Test-tube cloningTest-tube cloning Protoplast fusionProtoplast fusion with tissue culture methods with tissue culture methods

to invent new plant varieties (hybrids) that can to invent new plant varieties (hybrids) that can be cloned (protoplast=plant cell with wall be cloned (protoplast=plant cell with wall removed by enzyme treatment)removed by enzyme treatment)

Plant Responses to Plant Responses to Internal and External Internal and External

SignalsSignals Plants receive specific signals and respond to them in Plants receive specific signals and respond to them in

ways that enhance survival and reproductionways that enhance survival and reproduction

EtiolationEtiolation: : the morphological adaptation for growing the morphological adaptation for growing in the darkin the dark

De-etiolationDe-etiolation: : the change that plants undergo when the change that plants undergo when shoot reaches lightshoot reaches light Stem elongation slows, leaves expand, roots elongate, & Stem elongation slows, leaves expand, roots elongate, &

shoot produces chlorophyllshoot produces chlorophyll

ReceptionReception

Signals are first detected Signals are first detected by by receptorsreceptors, proteins , proteins that undergo changes & that undergo changes & shape in response to a shape in response to a specific stimulusspecific stimulus

Receptor involved in de-Receptor involved in de-etiolation is a type of etiolation is a type of phytochromephytochrome Located in cytoplasmLocated in cytoplasm

Receptors can be Receptors can be sensitive to weak sensitive to weak environmental or environmental or chemical signalschemical signals

TransductionTransduction

Some de-etiolation responses=triggered by Some de-etiolation responses=triggered by extremely low levels of lifeextremely low levels of life

Second messengersSecond messengers=small molecules & ions =small molecules & ions that amplify signal & transfer it from receptor to that amplify signal & transfer it from receptor to other proteins that carry out responseother proteins that carry out response

Ca2+ & cyclic GMP=second messengers in de-Ca2+ & cyclic GMP=second messengers in de-etiolationetiolation

Changes in Ca2+ levels=important in Changes in Ca2+ levels=important in photochrome signal transduction photochrome signal transduction

Photochrome activationPhotochrome activation opening of Ca2+ opening of Ca2+ channels & a transient 100-fold increase in channels & a transient 100-fold increase in cytosolic Ca2+ levels cytosolic Ca2+ levels

Photochrome changes shape, which leads to Photochrome changes shape, which leads to activation of activation of guanylyl cyclaseguanylyl cyclase

cGmp induces cGmp induces partial de-etiolation response partial de-etiolation response

ResponseResponse

Involves increased activity of enzymesInvolves increased activity of enzymes

2 mechanisms that can enhance an enzymatic 2 mechanisms that can enhance an enzymatic step in a biochemical pathway=step in a biochemical pathway=

1)1) post-translational modificationpost-translational modification

2) transcriptional regulation2) transcriptional regulation post-translational modification- activates pre-post-translational modification- activates pre-

existing enzymesexisting enzymes transcriptional regulation- increases/decreases transcriptional regulation- increases/decreases

the synthesis of mRNA encoding a specific the synthesis of mRNA encoding a specific enzymeenzyme

Overview of Reception, Transduction, Response

Plant HormonesPlant Hormones

HormoneHormone=signaling molecule produced in organism’s =signaling molecule produced in organism’s body & transported to other parts, where it binds to body & transported to other parts, where it binds to specific receptor & triggers responses in target cells & specific receptor & triggers responses in target cells & tissuestissues Every aspect of plant growth & development=due to Every aspect of plant growth & development=due to

hormonal control hormonal control

TropismTropism=any growth response that results in plant =any growth response that results in plant organs curving toward/away from stimuliorgans curving toward/away from stimuli

Triple ResponseTriple Response=hormone that enables shoot to =hormone that enables shoot to avoid obstaclesavoid obstacles

SenescenceSenescence=programmed death of certain cells or =programmed death of certain cells or organs on the entire plantorgans on the entire plant

Plant Hormones Plant Hormones (continued)(continued)Hormone Function

Auxin Stimulates cell elongation, regulates branching and organ bending

Cytokinins Stimulate plant cell division; promote later bud growth; slow organ death

Gibberellins Promote stem elongation; helps seeds break dormancy and use stored reserves

Brassinosteriods Chemically similar to sex hormones of animals; induce elongation and division

Abscisic acid Promotes stomatal closure in response to drought; promotes seed dormancy

Strigolactones Regulate apical domiance, seed germination, and mycorrhizal associations

Ethylene Mediates fruit ripening

Responses to LightResponses to Light

Blue-light receptors: control hypocotyl elongation, stomatal opening, & phototropism

Red and Blue light=most important colors in regulation of plant’s photomorphogenesis (effects of light on

plant morphology)

Blue light initiates variety of responses in plants including phototropism, the light-induced opening of

stomata

3 types of pigments detecting blue light= 1) Cryptochromevs 2) Phototropin 3) Zeaxanthin

Phytochromes: help with information about light, help plants keep track of passage of days and seasons

Action spectrum: graph that depicts relative effectiveness of diff wavelengths of radiation in driving a particular process

Responses to light Responses to light ContinuedContinued

Circadian rhythms: physiological cycle of ~24 hrs that persists even in absence of external cues

Photoperiodism: physiological response to

photoperiod, such as flowering

Short-day plants require light period shorter than critical length to flowers

Long-day plants flower late in spring or early

summer, need longer than a certain number of hours

Day-neutral plants (tomatoes, rice,

dandelions)= unaffected by

photoperiod & flower when they reach a

certain stage of maturity

Reponses the light Reponses the light continuedcontinued

Plants detect direction, intensity, & wavelength (color)

Phytochrome conversion also provides info about relative length of day & night (photoperiod) & hence time of year

Photoperiodism regulates time of flowering in many species

Free-running circadian cycles ~24 hours

Florigen: hypothetical signaling molecule for flowering

Plant Response to Plant Response to StimuliStimuli

Gravitropism=response to gravity Occurs as soon as a seed germinates

Statoliths=dense cytoplasmic components that settle under influence of gravity to lower portions of the cell

Action potentials resemble nerve impulses in animals, but 1000x slower

Abiotic: nonliving stresses that plants encounter

Biotic: living stresses, such as herbivores and pathogens

Heat-shock proteins: help protect other proteins from heat stress

Environmental Environmental Stresses/ResponsesStresses/Responses

Environmental Stress Response

Drought ABA production, reducing water loss by closing stomata

Flooding Formation of air tubes that help roots survive oxygen deprivation

Salt Avoiding osmotic water loss by producing solutes tolerated at high concentration

Heat Synthesis of heat-shock proteins, which reduce protein denaturation at high temperatures

Cold Adjusting membrane fluidity; avoiding osmotic water loss; producing antifreeze proteins

Plant DefensePlant Defense

Plants respond to attacks by herbivores and pathogens

Physical defenses--thorns & trichromes

Produce chemicals=distasteful & toxic

1st line of defense: epidermis and periderm

2nd line of defense: chemical attack that destroys pathogen and prevents spread of infection

Plant has little specific defense against virulent pathogens

Avirulent pathogens: strains of pathogens that mildly harm but do not kill host plants

herbivorepathogen

Defense responses against an avirulent pathogen

Plants Defense Plants Defense (Continued)(Continued)

Gene-for-gene recognition=form of plant disease resistance in which pathogen-derived molecules (effectors) are recognized by one of the 100s of resistance genes in plant’s genome

Hypersensitive response: defense response that causes cell and tissue death near infection site

Systemic acquired resistance: arises from plant-wide expression of defense genes

Salicylic acid: activates signal transduction pthwy that induces production of pathogenesis-related (PR) proteins & resistance to pathogen attack

BibliographyBibliography Textbook Website in general: Textbook Website in general:

CHAPTER 38- Parts of flower, fertilization, male/female CHAPTER 38- Parts of flower, fertilization, male/female gametophytes, hummingbird, double fertilization, seed structure, gametophytes, hummingbird, double fertilization, seed structure, origin of fruits, and preventing self-fertilization CHAPTER 39- origin of fruits, and preventing self-fertilization CHAPTER 39- Reception and transduction and response, flowering hormone, and Reception and transduction and response, flowering hormone, and avirulent defense responsesavirulent defense responseshttp://view.ebookplus.pearsoncmg.com/ebook/launcheText.do?values=bookID::4487::platform::1004::invokeType::lms::launchState::goToEBook::scenarioid::scenario3::logoutplatform::1004::platform::1004::scenario::3::globalBookID::CM81419602::userID::1911037::pageid::::hsid::5434934bda1919e8fb46a13ad18940ba

(Chloroplast)-(Chloroplast)-http://www.google.com/imgres?imgurl=http://www.biologycorner.com/resources/chloroplast_labeled.jpg&imgrefurl=http://www.biologycorner.com/APbiology/cellular/notes_cells2.html&usg=__jt46BLhGK2kXtfsnXvEk_pehTOI=&h=273&w=240&sz=19&hl=en&start=1&zoom=1&tbnid=0GPQ6DgB0MPpSM:&tbnh=113&tbnw=99&ei=OeGWT8acB6rAiQfc4ZWgCg&prev=/search%3Fq%3Dlabeled%2Bchloroplast%26um%3D1%26hl%3Den%26sa%3DN%26gbv%3D2%26tbm%3Disch&um=1&itbs=1      

Bib Cntd.Bib Cntd.

(Linear electron flow)-(Linear electron flow)-http://www.bio.miami.edu/dana/pix/noncyclic.jpg

(Cyclic electron flow)- (Cyclic electron flow)- http://kvhs.nbed.nb.ca/gallant/biology/cyclic_electron_flow.jpg  

(C3 and C4 plant)- (C3 and C4 plant)- http://www.google.com/imgres?q=c3+and+c4+plants&hl=en&biw=1203&bih=629&gbv=2&tbm=isch&tbnid=HVXznDU79kIssM:&imgrefurl=http://www.nature.com/scitable/content/each-plant-species-utilizes-one-of-several-13311179&docid=ST2PXVLQNsCjcM&imgurl=http://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/13311179/taub_figure2_ksm.jpg&w=500&h=384&ei=sHSdT9fpC8nMiQKx8fBE&zoom=1&iact=hc&vpx=828&vpy=178&dur=661&hovh=197&hovw=256&tx=134&ty=110&sig=112547099696337624223&page=1&tbnh=122&tbnw=159&start=0&ndsp=18&ved=1t:429,r:4,s:0,i:91

Bib Cntd.Bib Cntd. (CAM plant)- (CAM plant)-

http://www.google.com/imgres?q=c3+and+c4+plants&hl=en&biw=1203&bih=629&gbv=2&tbm=isch&tbnid=5Wn-TnII7WaFSM:&imgrefurl=http://ihatecreataccount.blogspot.com/&docid=u6rKD-Gr1qVHqM&imgurl=http://4.bp.blogspot.com/-8mocbeEDyAE/TfzKBj9B4lI/AAAAAAAAABA/-l-B3ghAZ3s/s1600/C4-and-CAM-plants.jpg&w=614&h=602&ei=sHSdT9fpC8nMiQKx8fBE&zoom=1&iact=hc&vpx=937&vpy=73&dur=383&hovh=222&hovw=227&tx=155&ty=169&sig=112547099696337624223&page=1&tbnh=122&tbnw=124&start=0&ndsp=18&ved=1t:429,r:5,s:0,i:93

(Mitochondria)-(Mitochondria)-http://www.google.com/imgres?q=mitochondria&num=10&hl=en&gbv=2&biw=1203&bih=629&tbm=isch&tbnid=7G9QL6X6c6JrGM:&imgrefurl=http://micro.magnet.fsu.edu/cells/mitochondria/mitochondria.html&docid=Fzfn06X-Mo1mlM&imgurl=http://micro.magnet.fsu.edu/cells/mitochondria/images/mitochondriafigure1.jpg&w=296&h=312&ei=93SdT6maF9PbiALUtPRg&zoom=1&iact=rc&dur=403&sig=112547099696337624223&sqi=2&page=1&tbnh=124&tbnw=118&start=0&ndsp=19&ved=1t:429,r:1,s:0,i:109&tx=45&ty=26

Bib Cntd.Bib Cntd.

(Calvin Cycle)-(Calvin Cycle)-http://www.emc.maricopa.edu/faculty/farabee/biobk/alcferm.gif

(Fermentation)-(Fermentation)-http://galvez-808.cghub.com/files/Image/086001-087000/86629/095_stream.jpg

(Sun)-(Sun)-http://www.google.com/imgres?q=the+sun&um=1&hl=en&sa=N&biw=1203&bih=629&tbm=isch&tbnid=eRnRauaHGhZV4M:&imgrefurl=http://www.bobthealien.co.uk/sun.htm&docid=2Zh8xL_2UaBKCM&imgurl=http://www.bobthealien.co.uk/sunmain2.png&w=320&h=320&ei=l4udT72rDqGSiQKrn7x4&zoom=1&iact=rc&dur=205&sig=112547099696337624223&page=1&tbnh=125&tbnw=124&start=0&ndsp=21&ved=1t:429,r:12,s:0,i:160&tx=94&ty=74

Bib Cntd.Bib Cntd.

(Tomato)-http://www.google.com/imgres?q=tomatoes&um=1&hl=en&sa=N&biw=1203&bih=629&tbm=isch&tbnid=-DcjM3eIeLrVNM:&imgrefurl=http://www.bewellbuzz.com/general/what-you-didnt-know-about-tomatoes/&docid=rci-XKvrxbp8xM&imgurl=http://cdn.bewellbuzz.com/wpcontent/uploads/2009/06/tomatoes=293x300.jpg&w=293&h=300&ei=Bo2dT6PfLsjhiAKH3OmkAQ&zoom=1&iact=hc&vpx=672&vpy=168&dur=233&hovh=227&hovw=222&tx=128&ty=73&sig=112547099696337624223&page=1&tbnh=132&tbnw=129&start=0&ndsp=20&ved=1t:429,r:4,s:0,i:143

(Reception, transduction, response)- (Reception, transduction, response)- http://view.ebookplus.pearsoncmg.com/ebook/launcheText.do?values=bookID::4487::platform::1004::invokeType::lms::launchState::goToEBook::scenarioid::scenario3::logoutplatform::1004::platform::1004::scenario::3::globalBookID::CM81419602::userID::1911037::pageid::::hsid::5434934bda1919e8fb46a13ad18940ba

Bib Cntd.Bib Cntd.

(Gravitropism leaf)-(Gravitropism leaf)-http://www.google.com/imgres?q=gravitropism&hl=en&gbv=2&biw=1203&bih=651&tbm=isch&tbnid=DyjaGkCPk7oHBM:&imgrefurl=http://herbarium.desu.edu/pfk/page8/page9/page9.html&docid=zfQ1M6RevvnjYM&imgurl=http://herbarium.desu.edu/pfk/page8/page9/files/page9_1.jpg&w=301&h=265&ei=QS6eT-4G5JqIAuyF-Hg&zoom=1&iact=rc&dur=488&sig=112547099696337624223&page=1&tbnh=145&tbnw=165&start=0&ndsp=19&ved=1t:429,r:3,s:0,i:76&tx=104&ty=67

(Herbivore)-(Herbivore)-http://www.google.com/imgres?http://www.google.com/imgres?q=herbivores&um=1&hl=en&sa=N&biw=1203&bih=629&tbm=ischq=herbivores&um=1&hl=en&sa=N&biw=1203&bih=629&tbm=isch&tbnid=NcMGzieuixaetM:&imgrefurl=http://&tbnid=NcMGzieuixaetM:&imgrefurl=http://www.qrg.northwestern.edu/projects/marssim/simhtml/info/whats-a-www.qrg.northwestern.edu/projects/marssim/simhtml/info/whats-a-herbivore.html&docid=4j8edxN7tTtbCM&imgurl=http://herbivore.html&docid=4j8edxN7tTtbCM&imgurl=http://www.qrg.northwestern.edu/projects/marssim/simhtml/pics-for-sim/www.qrg.northwestern.edu/projects/marssim/simhtml/pics-for-sim/pronghorn.jpg&w=215&h=198&ei=FC-eT8-pronghorn.jpg&w=215&h=198&ei=FC-eT8-DKeSpiALYyeCcAQ&zoom=1&iact=rc&dur=291&sig=112547099696DKeSpiALYyeCcAQ&zoom=1&iact=rc&dur=291&sig=112547099696337624223&page=1&tbnh=125&tbnw=123&start=0&ndsp=20&ve337624223&page=1&tbnh=125&tbnw=123&start=0&ndsp=20&ved=1t:429,r:0,s:0,i:135&tx=86&ty=40d=1t:429,r:0,s:0,i:135&tx=86&ty=40

Bib Cntd.Bib Cntd.

(Grafting)-(Grafting)-http://www.google.com/imgres?http://www.google.com/imgres?q=grafting+of+plants&num=10&um=1&hl=en&biw=1203&bih=651q=grafting+of+plants&num=10&um=1&hl=en&biw=1203&bih=651&tbm=isch&tbnid=oSjdfEPHjhuwiM:&imgrefurl=http://anpsa.org.au/&tbm=isch&tbnid=oSjdfEPHjhuwiM:&imgrefurl=http://anpsa.org.au/grafting.html&docid=O4TojW7M8_dPMM&imgurl=http://grafting.html&docid=O4TojW7M8_dPMM&imgurl=http://anpsa.org.au/gif/grafta.gif&w=261&h=341&ei=ryKeT4KNJ4-anpsa.org.au/gif/grafta.gif&w=261&h=341&ei=ryKeT4KNJ4-NigLBqMWZAQ&zoom=1&iact=rc&dur=382&sig=112547099696337NigLBqMWZAQ&zoom=1&iact=rc&dur=382&sig=112547099696337624223&sqi=2&page=1&tbnh=133&tbnw=102&start=0&ndsp=21&624223&sqi=2&page=1&tbnh=133&tbnw=102&start=0&ndsp=21&ved=1t:429,r:8,s:0,i:84&tx=63&ty=44ved=1t:429,r:8,s:0,i:84&tx=63&ty=44

(Pathogen)-(Pathogen)-http://www.google.com/imgres?http://www.google.com/imgres?q=pathogen&um=1&hl=en&sa=N&biw=1203&bih=629&tbm=ischq=pathogen&um=1&hl=en&sa=N&biw=1203&bih=629&tbm=isch&tbnid=v2OabBWgeetIRM:&imgrefurl=http://www.beltina.org/&tbnid=v2OabBWgeetIRM:&imgrefurl=http://www.beltina.org/health-dictionary/pathogen-definition-what-health-dictionary/pathogen-definition-what-is.html&docid=LpmLvh6jzfJ3dM&imgurl=http://www.beltina.org/is.html&docid=LpmLvh6jzfJ3dM&imgurl=http://www.beltina.org/pics/pathogen.jpg&w=291&h=284&ei=YC-pics/pathogen.jpg&w=291&h=284&ei=YC-eT7v9D8muiAL9wtCiAQ&zoom=1&iact=hc&vpx=112&vpy=167&dueT7v9D8muiAL9wtCiAQ&zoom=1&iact=hc&vpx=112&vpy=167&dur=740&hovh=222&hovw=227&tx=140&ty=135&sig=11254709969r=740&hovh=222&hovw=227&tx=140&ty=135&sig=112547099696337624223&page=1&tbnh=126&tbnw=130&start=0&ndsp=21&v6337624223&page=1&tbnh=126&tbnw=130&start=0&ndsp=21&ved=1t:429,r:0,s:0,i:135ed=1t:429,r:0,s:0,i:135

Bib Cntd.Bib Cntd.

(Hypersensitive response (Hypersensitive response leaf)-leaf)-http://www.google.com/imgres?http://www.google.com/imgres?q=hypersensitive+response&um=1&hl=en&sa=N&biw=1002&bih=q=hypersensitive+response&um=1&hl=en&sa=N&biw=1002&bih=524&tbm=isch&tbnid=6osVRRAmmlx0tM:&imgrefurl=http://524&tbm=isch&tbnid=6osVRRAmmlx0tM:&imgrefurl=http://www.sidthomas.net/SenEssence/Development/www.sidthomas.net/SenEssence/Development/devexamples.htm&docid=0hSHRJW6boWvbM&imgurl=http://devexamples.htm&docid=0hSHRJW6boWvbM&imgurl=http://www.sidthomas.net/images/www.sidthomas.net/images/hypersensitive.jpg&w=400&h=300&ei=3DOeT8PmGYSXiALWtKCeAQhypersensitive.jpg&w=400&h=300&ei=3DOeT8PmGYSXiALWtKCeAQ&zoom=1&iact=rc&dur=483&sig=112547099696337624223&page&zoom=1&iact=rc&dur=483&sig=112547099696337624223&page=1&tbnh=159&tbnw=218&start=0&ndsp=8&ved=1t:429,r:1,s:0,i:7=1&tbnh=159&tbnw=218&start=0&ndsp=8&ved=1t:429,r:1,s:0,i:71&tx=126&ty=591&tx=126&ty=59