Growth of tissues and stems
Concepts
Basic Types of Cells and Tissues
Internal organization
External Organization of Stems
Stem growth and differentiation
Herb
Stem
Root
Leaves
Absorptive"mud"cells
Can not be photosynthesized
sugar must be transported down
survival
Above dies, under lives
Dispersal
Runners, breaks, carried
grow new plants
Harrisella porrecta
consist of green photosyn. roots connected to stem , roots make up almost body, shoots active only when producing
Campylocentrum Pachyrrhizum #
two theories #
- Mutauition enhanced abitilites to absorb CO2 and do photostyn.
- Mutattion cause them to conserve more water
Tillandsia Straminea
Herbaceous vines
lay on top of the soil
absorb moisture
for production of horomones
Angiosperms
Flowering plants
largest division in the plant kingdom
297,000 species
Magnoliophyta
Basal
monocots
Eudicots
waterlilies, magnolias, laurels
roses, asters, maples,
cattails, lilies, palms, philodendrons, bromeliads
Primary plant body
Secondary plant body
Herbaceous body
woody body
collenchyma
Sclerenchyma
Parachyma
Mainly thin walls #
Parachyma tissue
mass of parachyma tissues
most common type of cell ans tissue, all soft parts of flower
sub types
Glandular cells
Transfer cells
chlorenchyma
Involved in photosynthesis
Numerous chloroplasts
Thin walls let light and CO2 pass through
to the chloroplast
Contain a few chloroplast
have elevated dytosomes and Endoplasmic R.
Transport sugar and mineral into themselves transform them and send the out
Secrete nectar, fragrance, mucilage, resins, and oils
mediate distance transport by large plasma membrane
capable of holding numerous molecular pumps
increase surface area, having extensive knobs ridges, ingrowths on the inner surface of walls
function by dying at maturity
conduct nutrients over a long distance
phloem
inexpensive to build
little glucose used to build thin walls
80 to 100 nm thick
just 5 to 10 layers of cellulose micro fibrils
walls thin in some areas, thick in other-(corners)
the ability to deform by pressure, tension, retain new shape
long and flexible shoot root (like grape vines)
can stretch, located as a layer under the epidermis or as bands next to vascular bundles
can be damaged by wind
collenchyma & parachyma work together
like air pressure to a tire #
require more glucose for production
has both a primary wall and a thick secondary that is almost/ always lignified
walls are elastic
can be deformed, return back to original size and shape when pressure is released
develop in parachyma cells in mature organs
after no growth, achieved proper shape
deforming forces
wind
snow
animals
supports the plant by strength alone
mechanical sclernchymal
strong enough to prevent the protoplast from expanding
Conducting sclernchyma
fiber-rich bark resists
fungi
other pests
insects
Scereids
short
strong walls in all 3 dimensions
Sclerenchyma tissues
act brittle and inflexible
masses are hard, impenetrable
flexibility would be a disadvantage example (brain and skull)
Shoot
stem
stem plus any leaves, flowers buds present
is the Axis
Node
Leaves are attached
Inter nodes
The region between nodes
Leaf axil
the stem area just above the point where a leaf attaches
bud scales
Axillary bud
A mini shoot with a dormant apical meristem &several young leaves
either a vegeative bud (branch or floral bud.
small, corky, waxy leaves that protect the organs
terminal bud
the extreme tip of each stem
Phyllotaxy
the arrangement of leaves on the stem
important no shading each other
Opposite
Alternate
Whorled
2 per node
3 or more per node
1 per node
Tendrils
modified leaves or branches capable of twining around small objects
Stolons (Runners)
the capacity to explore is even more advanced
Internodes are long and thin
Leaves dont expand
if older part of the plant dies
vertical shoots become a new plant
Bulbs
are short shoots (thick) fleshy leaves
Corms
vertical (thick) stems that have thin papery leaves
Rhizomes
are fleshy horizontal leaves that allows a plant to spread underground
tubers
Horizontal, grow for short period, mainly means of storing nutrients
Bulky underground plant organ
storage shoots are subterranean
Trunk
Allowing the plant to reach brighter light in the top of the forest canopy
Vascular tissues
Xylem
Epidermis
Cortex
prevents water loss
barrier against
the outermost surface of a herbaceous stem
shields delicate internal cells
a single layer of parachyma cells
fungi
small insects
bacteria
passing animals
leaves and stems that might be to close
dust
protects plants from overheating in bright sunlight
Cutin
a fatty substance that makes the wall impenetrable to water
Cuticle
builds up as more or less pure layers
Guard cells
with a hole
stomatal pore
in between them
work together to make the stoma
open up in the daytime letting CO2 enter the plant
swell by absorbing water
trichomes (hairs)
epidermal cells elongate outward
make it difficult for animals to land, walk chew on leaf
shade underlying tissues by blocking some incoming sunlight
create immobile air next to the leaf surface
Allows water molecules to diffuse out of the stoma to bounce back in rather than be swept away by air currents
occurs in many shapes and sizes
stinging nettle
Interior to the epidermis
cells contain large crystals of calcium oxalate or deposits of silica
Arenchyma
an open tissue with large inter cellular air spaces
Xylem
Phloem
conducts water and minerals
Distributes sugar and minerals
not a circulatory system
water and minerals enter through roots and are conducted upward to leaves and stems
sap travels through dead, hollow cells not through living cells
living cells
once in shoots water evaporates from surface if stem, leaves flowers and is lost
the minerals and a bit of water are used by surrounding cells
pick up sugar from areas where it is abundant
usually leaves during the summer and tubers or rhizomes in spring and transport to where sugar is needed
growing tips of shoots, roots, young leaves and flowers
Summer carries sugar into developing fruits and into the storage organs of perennial plants
because sugar is dissolved to be conducted water is transported simultaneously
two types of conductor cells
Tracheids elements #
Vessel elements #
Annular thickening
Simplest type of element, small amount of secondary wall, organized as a set of rings
Helical thickening
does not provide strength
the 2ndary wall exist as one to three helices interior to the primary wall
Scalariform thickening
provides much more strength because the 2ndary wall underlies most of the inner surface of the primary wall and is fairly extensive
Reticulate thickening
the 2ndary wall is deposited in the shape of a net as the name suggests.
Circular bordered pits
the most derived and strongest tracheary elements
Perforation
Vessels
an entire sack of vessle elements
is digested through a particular site if the primary wall, often removing the entire end wall
Phloem #
Two conducting cells
Plasmodesma
Sieve cells
sieve pores
sieve tube membrane
immature sieve begin to differ, their plasmodesmata enlarge to a diameter of more than 1 *m
occurs in groups ( primary pits fields);
therefore; sieve pores also occur clustered together in groups called
sieve area
sieve elements
remain alive during differentiation
Plasma membrane that lined the plasmodesma continues to line the sieve pore
apical meristems
stems grow longer by tips
subapical stem
under the apical stem
Protophloem
exterior mature vascular bundles
Metaphloem
cells closest to the metaxylem