Ex. 3 Plant Structure and Development Flashcards
what are the 2 main parts of the leaf?
blade
petiole (joins blade to stem at the node)
terminal bud
a bud located at the apex (tip) of the stem. Terminal buds have special tissue, called apical meristem, consisting of cells that can divide indefinitely
axillary bud
an embryonic shoot located in the axil of a leaf
-almost all branches in angiosperms begin as axillary buds
lead primordia
developing leaves
-expand rapidly
trichomes
tiny hairs on leaves
shoot apical meristem
dome shaped mass of cells at the apex of the stem
- dark colored, stain darkly
- dense cytoplasm/small vacuoles
axillary bud primordia
located in the axil of each leaf primordium
-will become apical meristems for new lateral branches
protoderm
tissue that will give rise to the epidermis
-outermost layer of cells
procambium
tissue that will differentiate into the vascular system of the leaves and stem
-darkly stained and run down the middle of the leaf primordia
ground meristem
tissue that will become the pith and cortex of the stem and the mesophyll of the leaves
-any cells that aren’t protoderm or procambium
epidermis
outermost layer of cells
cortex
layer between epidermis and vascular bundles
-composed of parenchyma cells
vascular bundles
found beneath the cortex
include xylem and phloem
xylem
conduct water and minerals
- stain red in prepared slides (presence of lignin)
- found one layer deeper toward pith than phloem
phloem
found right next to xylem closer to epidermis than xylem is
- conduct nutrients
- composed of sieve-tube elements and companion cells
vascular cambium
located between xylem and phloem
-responsible for generating new vascular tissue
pith
core of parenchyma cells in the center of the stem
dermal tissues
- epidermis (guard cells)
2. periderm (parenchyma, sclerenchyma, cork cells)
ground tissues
parenchyma
collenchyma
sclerenchyma
vascular tissues
xylem (tracheids, vessel elements)
phloem (sieve-tube elements, companion cells)
what do roots do?
- anchor the plant
2. absorb water and mineral nutrients from the soil
what do stems do?
- support and elevate leaves
- transport water and nutrients
- provide place for plants to keep flowers and fruits
- keep leaves in the light
root cap
The root cap protects the growing tip in plants. It secretes mucilage to ease the movement of the root through soil, and may also be involved in communication with the soil microbiota
3 zones of growth in the root tip
- zone of cell division (meristematic region, darkly stained)
- zone of elongation (cells get longer)
- zone of maturation (have root hairs)
root hair
extensions of epidermal cells
- help hold the root in place/increase surface area for water absorption
- short lived
endodermis of roots
circular bands of cells in the center of the root
- surround central vascular tissue
- cell walls of endodermis contain “suberin” which stain red
- suberin prevents water and minerals from flowing through the cell walls of the endodermis, forces them to move through cytoplasm
“stele” of roots. what are the 3 main parts?
central tissue which contains vascular tissue
- pericycle (undifferentiated perenchyma cells)
- xylem (star shaped)
- phloem (stained blue, found in between xylem)
what are the 4 layers of leaves?
- upper epidermis
- palisade mesophyll (electrons bouncing, tightly packed)
- spongy mesophyll (gas exchange, much space)
- lower epidermis
* cuticles also enclose the leaf
stomata
found only in lower epidermis
- open and close for gas exchange
- contain guard cells
cork and cork cambium
cork - layer of pink staining cells that cover the stem surface (about 5 cells deep)
cork cambium - directly beneath the cork, single layer of meristematic tissue that produces new cork cells
define cotyldon
an embryonic leaf in seed-bearing plants, one or more of which are the first leaves to appear from a germinating seed
what are the two major subgroups of angiosperms?
monocots
eudicots
