Biotic stress (mujahid hussain 127)
-
Upload
mujahid-hussaini -
Category
Science
-
view
855 -
download
6
Transcript of Biotic stress (mujahid hussain 127)
![Page 1: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/1.jpg)
Biotic stress
![Page 2: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/2.jpg)
Stress
Difficulty that cause worry Or an Environmental damage to plants
Biotic abioticResistance : The adaptability of plants to adverse environment
◇Stress avoidance ◇ Stress tolerance
![Page 3: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/3.jpg)
Plants are sessile and must deal with stresses in placePlants cannot avoid stress after
germinationHow plants deal with stress has
implications in Ecology: Stress responses help explain
geographic distribution of speciesCrop science: Stress affects productivityPhysiology and biochemistry: Stress affects
the metabolism of plants and results in changes in gene expression
![Page 4: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/4.jpg)
Plants are sessile and must deal with stresses in place• From engineering, stresses cause
strains (responses of stressed objects) = changes in gene expression and metabolism in plants
• Biological stress difficult to define/quantify:
![Page 5: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/5.jpg)
Types of stress
![Page 6: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/6.jpg)
Types of resistance
![Page 7: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/7.jpg)
Biotic Stress and Plant Defense Responses Pathogen Strategies1. Necrotrophic – plant tissue killed and then
colonized; broad host rangee.g., rotting bacteria (Erwinia)
2. Biotrophic – plant cells remain alive, narrow host range (1 plant species)
e.g., viruses, nematodes, fungal mildews
![Page 8: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/8.jpg)
What causes a plant to be stressed? As with humans, stresses can originate from the surrounding environment (called abiotic, or nonliving stresses); or, they can come from living organisms that can cause disease or damage (caused biotic stresses).
![Page 9: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/9.jpg)
Biotic stressBiotic Stress is stress that occurs as
a result of damage done to plants by other living organisms, such as bacteria, viruses (although they are not considered to be living organisms, also cause biotic stress to plants), fungi, parasites, beneficial and harmful insects, weeds, and cultivated or native plants.
![Page 10: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/10.jpg)
Biotic stressThe damage caused by these various living and nonliving agents can appear very similar.[2] Even with close observation, accurate diagnosis can be difficult.
![Page 11: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/11.jpg)
Biotic stressFor example, browning of leaves on an oak treecaused by drought stress may appear similar to leaf browning caused by oak wilt, a serious vascular disease, or the browning cause by anthracnose, a fairly minor leaf disease.
![Page 12: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/12.jpg)
Agriculture
It is a major focus of agricultural research, due to the vast economic losses caused by biotic stress to cash crops.
![Page 13: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/13.jpg)
Agriculture The relationship between biotic stress and plant yield affects economic decisions as well as practical development.
![Page 14: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/14.jpg)
Agriculture Plants are exposed to many stress
factors, such as drought, high salinity or pathogens, which reduce the yield of the cultivated plants or affect the quality of the harvested products. Arabidopsis thaliana is often used as a model plant to study the responses of plants to different sources of stress.[5]
![Page 15: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/15.jpg)
Biotic stressesFungi cause more diseases in plants than any other biotic stress factor.
Over 8,000 fungal species are known to cause plant disease.
On the other hand, only about 14 bacterial genera cause economically important diseases in plants,
![Page 16: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/16.jpg)
Biotic stresses According to an Ohio State University Extension publication.
Not many plant pathogenic viruses exist, but they are serious enough to cause nearly as much crop damage worldwide as fungi,
![Page 17: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/17.jpg)
Microorganisms can cause plant wilt,
leaf spots, root rot, or seed damage.
. Insects can cause severe physical damage to plants, including to the leaves, stem, bark, and flowers. Insects can also act as a vector of viruses and bacteria from infected plants to healthy plants.
![Page 18: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/18.jpg)
Biotic stressesThe method by which weeds, considered as
unwanted and unprofitable plants, inhibit the growth of desirable plants such as crops or flowers is not by direct damage, but by competing with the desirable plants for space and nutrients.
Because weeds grow quickly and produce an abundance of viable seed, they are often able to dominate environments more quickly than some desirable plants.
![Page 19: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/19.jpg)
Plant defenses1) Physical barriers: cuticle, thorns, cell walls2) Constitutively produced chemicals (e.g.,
phytoalexins) and proteins (e.g., Ricin) 3) Induced responses (a.k.a., the Plant Defense
Response)
![Page 20: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/20.jpg)
Plant defense
![Page 21: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/21.jpg)
Ephemeral plants
Ephemeral plants avoid stress in US desert Only bloom after wet winterDie before summer returns
![Page 22: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/22.jpg)
Alfalfa & CAM plants Avoidance also possible by
morphological adaptationsDeep tap roots in alfalfa allow growth in
arid conditions– Desert CAM plants store H2O in fleshy
photosynthetic stems. Adaptation: heritable modifications to increase fitness
• CAM plants’ morphological and physiological adaptations to low H2O environment
![Page 23: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/23.jpg)
FernsStress resistant plants can tolerate a particular stress
Resurrection plants (ferns) can tolerate dessication of protoplasm to <7% H2O can rehydrate dried leaves
Plants may become stress tolerant through
![Page 24: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/24.jpg)
Cold hardy plants–Acclimation: non heritable physiological and biochemical gene expression• Cold hardening induced by gradual exposure to chilling temps, cold-hardy plants
![Page 25: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/25.jpg)
Pathogen invasion
![Page 26: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/26.jpg)
Pathogen invasionApoptosis : Cell suiside mechanism.
at invasion site to physically cut off rest of plant
![Page 27: Biotic stress (mujahid hussain 127)](https://reader034.fdocuments.net/reader034/viewer/2022051101/5873c8cd1a28ab9d168b4863/html5/thumbnails/27.jpg)
Assignment of : physiology Submitted to : Dr. ameer Submitted by : Mujahid hussain Roll No. : 127 Class : Bs botany 6th (S.S)
UNIVERSITY OF SARGODHA THANK YOU