Lecture 4 -- Plants Flashcards
what is the cell wall made from
the cell membrane
what are the main polysaccharides holding the fibrils together
pectin, hemicellulose, and microfibril
when is the secondary cell wall made
after the primary cell wall
what is the outermost wall
the primary cell wall
dermal
outermost layer - single layer
vascular
moves fluid around
ground
all of the other stuff
epidermal cells
form single layer on outside of plants – always outermost unless woody.
waterproofs cell – cuticle waxy covering involved in waterproofing
most general type of ground tissue is
parenchyma cells.
parenchyma cells
type of ground tissue, takes care of metabolic processes (photosynthesis, storage), lacks secondary cell wall - mostly. and differentiates at maturity.
examples of parenchyma cells
fruit flesh, endosperm, pith + cortex
collenchyma cells
provide support / stiff, supports especially young and growing organs, unevenly thick primary cell wall, NO secondary wall, ALWAYS JUST BELOW EPIDERMIS, type of ground tissue
examples of collenchyma cells
rib of celery.
Sclerenchyma cells
‘scelere’ means hard. has thick secondary cell wall with lignin, does not continue to divide once mature, supports, protection of tissues no longer elongating, cannot elongate at maturity, 2 forms fibres, and scliereids.
fibres examples
hemp, burap,
scliereids examples
pear – what makes it gritty.
water-conducting cells of XYLEM
tracheids and vessel elements, make up vascular tissue, move water upward from soil to plant, support and supply of water and minerals, dead at maturity (when doing their thing they are dead) secondary wall is lignified, often spiral, and tracheas and vessels differ in shape
tracheids shape
narrow, tapered, pits allow water flow
vessels shape
wider, like soup cans stacked on top of each other.
programmed cell death 3 steps
becomes trashed :
1. cytoplasm moving,
2. secondary cell wall formed,
3. death (vacuole implodes)
lignin
2nd most abundant natural polymer NOT polysaccharide, fills spaces and bonds cellulose, hemicellulose, and pectin, occurs in anything that SEEMS woody, (palm trees, bamboo)
sugar conducing cells of phloem:
sleeve tube elements. type of vascular tissue, transports sugars, hormones, and some minerals, alive at maturity, with companion cell (parenchyma)
plants grow from WHAT
meristems
what are meristems
they remain, and can divide forever, ultimate source of all parts of mature sporophyte, undifferentiated.
locations and types of meristems
Apical meristems (AM) - root and shoot, primary growth.
Lateral meristems – occurs in truly woody plants, vascular cambium, and cork cambium , secondary growth.
what does secondary growth mean for woody plants
growth in diameter and production of the wood.
shoot apical meristem (SAM)
all other cells come from the SAM : lead primordial, young leaf, …
the 3 tissue systems and where they come from
dermal, vascular, ground all come from the same apical meristem
Apical meristem
source of primary growth of both shoot and root. makes three other meristems
what three other meristems are made from apical meristem
protoderm – turns into epidermis (dermal tissue)
procambium – turns into vascular tissue
ground meristem – turns into ground tissue
view of the shoot draw and label
should have a peak where SAM is, next to it a leaf, outer part is labeled protoderm, then from leaf to other “shoot” little dashed lines which are the pro cambium, the a little axillary bud between other “shoot” and SAM, and everything else inside is the ground meristem.
shoot structure and development, draw cross sections of young shoots for eudicot and monocot.
circle for each, vascular bundles in ring in eudicot, and bundles scattered for monocot. epidermis outer layer for both, inside material is ground tissue for both, xylem on inside, phloem on outside of vascular bundle,
root apical meristems make three meristems as well, draw and label root,
upside-down U with cap, cap is called cap, right under cap, little collection of cells, that is the root apical meristem (RAM), then a tube like figure called the vascular cylinder/stele, the outer layer of that is the pro cambium, the very outer layer of whole thing is protoderm, everything else inside is ground meristem, near cap is zone of cell division, in middle is zone of elongation, and at bottom is zone of maturation.
what occurs in zone of maturation
root hairs form
what is the cap
a collection of dead cells
root hairs
single epidermal cells, increase the surface area, they emerge from the part of plant that has stopped moving.`
young root, eudicot and monocot draw and label
EUDICOT: circle – outer layer is the epidermis,, another small circle within– outer layer of that is the endodermis, area between large and small circle – cortex (ground tissue), stuff inside small circle – phloem, right after small circle – pericycle, x shape within small circle is – xylem
MONOCOT:
circle – outermost layer is epidermis, small circle outermost layer – endodermis, area between both circles is – cortex (ground tissue), area within small circle is – pith (ground tissue), scattered vascular bundles within small circle, – pointing inside is xylem and pointing outside is phloem.
what is everything is the endodermis called in the roots
called stele
young roots characteristics
endodermis is innermost layer of cortex, stele or vascular cylinder is. all cells inside endodermis; arise from pro cambium
lateral root
originates in pericycle (outermost layer of vascular cylinder), grows out through context and epidermis
SUMMARY of structure of primary non-woody roots
root cap, root hairs, endodermis, vascular cylinfer
root cap – protects
root hairs – epidermal cells, increase absorption area
endodermis – innermost layer of cortex, surrounds vascular cylinder
vascular cylinder – centre of root; contains vascular tissues xylem and phloem, and some ground issue
