Plant Response Flashcards
Adaptations
Changes in a living organism in order to survive
What is plant growth regulated by?
Plant growth is regulated by external and internal factors
Name external factors that can affect a plant
Light
Gravity
Temperature
Water
What are internal factors that can affect plant growth
Growth regulators
Stimulus
Change in environment that caused an reaction in an organism
Response
Reaction of an organism to a stimulus
Tropism
Growth response of a plant to a stimulus
Positive tropism
Growth of plant towards stimulus
Negative tropism
Growth of plant away from stimulus
Adverse environment
Harsh conditions that can harm a plant
Name the 5 types of tropism
Phototropism
Geotropism
Hydrotropism
Thigmotropism
Chemotropism
What is phototropism
Growth response of a plant to light
What is geotropism
Growth response of a plant to gravity
What is chemotropism
Growth response of a plant to chemicals
What is hydrotropism
Growth response of a plant to water
What is thigmotropism
Growth response of a plant to touch
Describe phototropism
Shoot is positively phototropic
Root is negative phototrophic
Advantages of phototropism
Shoot absorbs more light- more photosynthesis
Roots anchor the plant into soil
Describe geotropism
Shoot negatively geotropic
Root positively geotrophic
Describe the advantages of geotropism
Plants anchored in the ground
Allows roots to absorb water and minerals
Describe hydrotropism
Root positively hydrotropic
Shoot negatively hydrotropic
Describe chemotropism and give an example not involving roots
Roots negatively chemotropism towards acid
Roots positively chemotropic towards minerals
Eg. Pollen tube grows towards chemicals released by ovule
Describe thigmotropism
Climbing plants have tendrils - wrap around objects for support (positively thigmotropic)
Roots grow away from stones in soil (negatively thigmotropic)
Describe the mechanism of phototropism
IAA is produced in the meristem of the stem tip. When light shines on one side of the plant. IAA diffuses down shady side.Causes cells to grow and elongate on shady side. The plant structure bends over towards light due to the growth differences
What is a growth regulator
chemical that controls the growth of a plant
Where are plant regulators transported
Vascular tissue
List the similarities between animal hormones and plant growth regulators
Produced in small amounts at one site and act in another site
Both transported in vascular tissue
Slow response time
Long lasting effect
What are growth promoters
Encourage the growth of plants
What are growth inhibitors
Stops/ prevents the growth of plants
Name a growth promoter and a growth inhibitor
Growth promoter- Auxins /IAA
Growth inhibitor-ethene
In the case of a growth inhibitor, name, state where it is produced and its affects
Ethene
Produced by stem nodes, ripe fruits and decaying leaves
It causes fruit ripen and leaves to fall and decay during autumn
Where is IAA/auxins produced
Meristem tissue in the roots and shoot tip
Name and briefly explain the affect of auxins
Fruit formation+flower formation
Apical dominance ( apical bud is cut so material buds can develop)
Cell division - weakens cell wall causing water to be absorbed, promotes growth
Root and shoot growth
Describe the effect of IAA on root and shoot growth
High concentrations of IAA inhibit root growth and encourage shoot growth
Low concentrations of IAA inhibit shoot growth and stimulate root growth
Name commercial use of growth regulators
Rooting power
Ethene ripens fruit
Seedless fruits
Weed killers (inhibits root growth)
Name ways that plants protect themselves against adverse external environment
Spines,thorns, stinging hair to stop being eaten by animals
Guard cells shrivel and close stomata: stop excess water loss
Stress proteins production: attack by microorganisms
Describe the procedure to investigate the effect of different concentrations IAA growth regulator on plant tissue
A serial dilation produced different concentrations of IAA. to ensure it is a fair test, each dish , expect the control, has 9ml of IAA solution diluted to different concentrations. Control dish has only water.
Place gridded acetate paper in the Petri dishes and place radish seeds evenly spaced on to the same line.secure using petroleum jelly.
Add filter paper and Cotten wool on top
Seal and stand on side to ensure the root grows down and shoot grows up.
Incubate @ 25C for 3-5 days
In investigate the effect of different concentrations IAA growth regulator on plant tissue, what was the plant tissue?
Radish seeds
In investigate the effect of different concentrations IAA growth regulator on plant tissue, what is the purpose of the acetate grid paper?
Count length of roots and shoots
In investigate the effect of different concentrations IAA growth regulator on plant tissue, what is the purpose of filter paper
Ensure root and shoot do not get tangled in cotton wool
In investigate the effect of different concentrations IAA growth regulator on plant tissue, what is the purpose of the cotton wool
soaked up IAA solution
Explain the Results In investigate the effect of different concentrations IAA growth regulator on plant tissue
Lengths of roots and shoot measured
The results are compared to the control results
High conc of IAA stimulated shoot growth ( long shoot). Inhibited root growth
Low conc of IAA- stimulate root growth( long root)
Inhibited shoot growth ( short shoot)
Control- root and shoot grew equal amounts
