Summary
Summary PLANT HORMONES
- Course
- Life Sciences
- Institution
- 12
PLANT HORMONES summary
[Show more]
Seller
Follow
Content preview
PLANT HORMONES- plants are living organisms; must grow and develop
- growth: increase in size
- development: changes during growth
GROWTH and DEVELOPMENT controlled by:
✴ genes
✴hormones
CHARACTERISTICS OF PLANT HORMONES:
1. organic chemical messengers
2. produced in one part of plant and transported in the phloem to another part
3. hormone affects growth and development of part called target organ
4. hormones work in small amounts
5. reaction to hormones is usually slow
In order to survive plants must grow in response to external stimuli.
Tropisms: growth responses to directional stimuli that are controlled by hormones.
PLANT HORMONES: 3 main groups
- GIBBERELLINS: produced in terminal buds of stem and roots, young leaves and
embryos
Function:
- stimulate stem elongation (plants grow taller)
- promote flowering
- stimulate germination of seeds
- encourage fruit development
- ABSCISSIC ACID: growth inhibiter and counteracts functioning of auxins. Helps
plant cope in stressful situations
Functions:
- slows growth down (causes dormancy of terminal buds and lateral buds in winter)
- causes dormancy of seeds (inhibits germination)
- promotes abscission of leaves and fruit (grow old and fall off)
- AUXINS: produced in apical regions of stems and roots. High concentration of
auxins in stems stimulates growth and high concentration of auxins in roots inhibits
growth.
, Functions:
- stimulate cell elongation
- stimulate development of fruit (seedless)
- control abscission of leaves and fruit
- stimulate development of adventitious roots in stem cuttings
- cause tropisims in stems and roots
- INHIBITS GROWTH OF LATERAL BRANCHES-APICAL DOMINANCE
Auxin produced at tip-high
concentration
Inhibit development
of lateral branches
Auxin concentration low
therefore lateral branches
grow well
APICAL DOMINANCE
THE USE OF PLANT HORMONES IN AGRICULTURE:
✦ root formation in cuttings
✦ production of seedless fruits
✦ ripening of fruits
✦ prevention of premature abscission of fruit
✦ increase size of fruits
✦ WEED CONTROL
The benefits of buying summaries with Stuvia:
Guaranteed quality through customer reviews
Stuvia customers have reviewed more than 700,000 summaries. This how you know that you are buying the best documents.
Quick and easy check-out
You can quickly pay through EFT, credit card or Stuvia-credit for the summaries. There is no membership needed.
Focus on what matters
Your fellow students write the study notes themselves, which is why the documents are always reliable and up-to-date. This ensures you quickly get to the core!
Frequently asked questions
What do I get when I buy this document?
You get a PDF, available immediately after your purchase. The purchased document is accessible anytime, anywhere and indefinitely through your profile.
Satisfaction guarantee: how does it work?
Our satisfaction guarantee ensures that you always find a study document that suits you well. You fill out a form, and our customer service team takes care of the rest.
Who am I buying this summary from?
Stuvia is a marketplace, so you are not buying this document from us, but from seller emmahayes. Stuvia facilitates payment to the seller.
Will I be stuck with a subscription?
No, you only buy this summary for R120,00. You're not tied to anything after your purchase.
Can Stuvia be trusted?
4.6 stars on Google & Trustpilot (+1000 reviews)
56326 documents were sold in the last 30 days
Founded in 2010, the go-to place to buy summaries for 14 years now