Intro Horticulture Exam 2

Know the 5 plant hormones (plant regulators)

-two forms: natural compounds and synthetic compounds

• auxins : indole acetic acid (IAA)

  • controls photropism and geotropism

  • prevemnts tillering ‘

  • can be herbicides

    • tumors and twisted growth can occure

• gibberellins control plangt height and how fast they grow taller

  • gibberellins stimulate seed germination

• ethylene

  • responsible for ripening of fruit and death of planst

  • gaseous

• absciscic acid (aba)

  • causes guard cells to close and puts the plant in dromancy

  • reduces transpiration

things to know:

why we pinch plants

the 5 classes of PGRs + where they are produced and their primary functions

define apical dominance + describe itsrole im plant production/;hpw it smanipulatwss

Lec 3/3/25: Plant Propagation

• How:art of the method

  • sbdn

• Why: science behind it

  • reasons for certain propagation procedures and why tgey are possible

• Plant: will dictste method selection

• because sees are derived from gametes, thye are a result od meisosis

  • evry seed is genetically distinct

• vegetative propagation rleies on mitosis

  • mitosis does not lead to rocmbination so offsprng is identical

Lect 3/6

preformed root initials are like root cells and are already differentiated into root tissue

Lecture 3/10 - SEEDS

• what are preformed root initials? - root buds that eriupt into adventuroous roots

• what Plant growth regulator promotes growth? - auxin

• aba promotes seed dormancy

seeds = dromant embryonic plant w a seed coat ans sored insedes

two parts

• embryo = baby

• other nutritional stuff

pollination

fertilization

cotyledons = first leaves that come/grow out of plant but may not be true leaves

what allows unique offspring? - meiosis and sexual reproduction

Requirements for seed germination

1. water

2. oxygen

3. minimum and optimal germination temperatures

4. light (quality, intensity, and duration

   1. phytochrome = a phot reversible plant pigment that exists in active or inactive from

      1. serves as a switvh mechansim whicj controls plant physiologiscsl activites liek germination

   2. red light stimulus = moves phytochrome from inactive to active

5. Lack of chemical dormancy

   1. many seeds contain abscisic acid (ABA) which counteracts GA to maintain seed dormancy

seed stratification vs seed scarification

straticfication = freezing see for later germination

scarification = breaking/removing seed coat

High ABA:GA ration suppress GA’s ability to uinitiate seed germination

• how to artificially induce germination

seed float test => if seed floats = seed coat has been compromised

• viable seeds sink