Plant Development. Flashcards
What is development?
Growth and differentiation of cells to become specialized in structure and function ( tissues and organs).
What is growth?
Increase in size due to cell division ( mitosis and cytokinesis) and cell expansion.
5 step development process
- Cell proliferation
- Programmed cell death
- Cell movement and expression
- Cell differentiation
- Cell-cell interactions
1-2= common in multicellular organisms
3= immobile, only control direction and orientation
4-5= plants->meristems, animals->stem cells.
Embryogenesis
- Starts w/fertilized egg
- Apical-Basal axis form
- Apical & Basal planes separate
- Radial axis form, depends on direction of cell division
- Cotyledons and meristems form
- Embryo continues to grow.
Primary Growth
Allows plant to grow through apical meristems w/o movement.
What do meristems do?
Allows plant to grow in all directions above the ground.
Differentiation of vegetative parts of the plant to reproductive.
- hours of day/night trigger this by the pigments that absorb light that start the production of the reproductive hormone.
Secondary Growth
- Only happens in woody plants
- Allows shoots and roots widen through lateral meristems
What are the benefits of secondary growth?
- Increase vascular tissue
- Increase support
- Increase protection
Parts of woody plants:
XYLEM- inner wood
PHOELM- outer bark
CORK CAMBIUM- outward growth, expands cortex
Wild type flower
Sepal, petal, stamen, carpel
Mutant 1 flower:
Carpel, stamen, stamen, carpel
Mutant 2 flower:
Sepal, sepal, carpel, carpel
Mutant 3 flower:
Sepal, petal, petal, sepal
Mutation pattern:
- Missing 2 of the 4 results in 3 different gene types.
- each is placed in 2 different whorls, resulting 4 different proteins
- 4 proteins make 4 different floral organs
