Grade 10 Exam  >  Grade 10 Notes  >  Biology for Grade 10  >  Plant Defence Responses

Plant Defence Responses | Biology for Grade 10 PDF Download

Plant Defences


Just like animals, plants are constantly defending themselves from attack from pathogens. Again like us, plants have physical and chemical defences which stop pathogens from infecting them and causing disease.

Physical Defences


Many plants are covered with a thick bark. This is an external layer of dead cells which forms a physical barrier against infection. In this way it is very much like our skin. Beyond bark, each plant cell has a cellulose cell wall which acts as another barrier against infection. Leaves are covered with a waxy cuticle which also stops their cells from becoming infected.

Chemical Defences

  • Some plants such as mint and witch hazel produce antibacterial chemicals. These limit the spread of bacteria that were not stopped by physical defences. These chemical defences are now used in antiseptics for humans.
  • Other plants, like stinging nettles, have developed poisons to stop themselves being eaten by herbivores. These do not defend plants from infection by pathogens.

Other Defences


Farmers can now genetically engineer crop plants to be resistant to infections.

Mechanical Plant Defences


Plants have also evolved other defences from attack. These defences are often to avoid being eaten by herbivores.

Thorns and Hairs


Plants like roses have evolved large thorns to avoid being eaten, while plants like cacti have evolved thin spines. These adaptations protect plants from damage and keeps their vital water stores safe.

Drooping leaves


The Mimosa pudica plant is very special. It has evolved to close its leaves and then point its stems towards the ground when touched by an insect as it lands on it, making it difficult for the insect to feed on the leaves.

Mimicry


Some plants have evolved the ability to mimic what is around them. The passion flower vine has evolved small yellow spots on its leaves. These look like the eggs left behind by butterflies. Female butterflies are unable to tell the difference between these and real eggs, so they lay eggs on other leaves to avoid competition when they 'might' turn into caterpillars. Therefore, the passion flower vine suffers less damage to its leaves from feeding caterpillars.

The document Plant Defence Responses | Biology for Grade 10 is a part of the Grade 10 Course Biology for Grade 10.
All you need of Grade 10 at this link: Grade 10
110 videos|93 docs|9 tests
110 videos|93 docs|9 tests
Download as PDF
Explore Courses for Grade 10 exam
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev
Related Searches

past year papers

,

Exam

,

Previous Year Questions with Solutions

,

Plant Defence Responses | Biology for Grade 10

,

shortcuts and tricks

,

pdf

,

MCQs

,

Plant Defence Responses | Biology for Grade 10

,

video lectures

,

mock tests for examination

,

study material

,

Viva Questions

,

Extra Questions

,

Summary

,

Objective type Questions

,

Free

,

Semester Notes

,

practice quizzes

,

Plant Defence Responses | Biology for Grade 10

,

Important questions

,

Sample Paper

,

ppt

;