Stems Flashcards
Main Functions of Stems
Support
– leaves and reproductive structures
Conduct
– water, dissolved minerals, carbohydrates
Produce new living tissues
– at apical meristems
– at lateral meristems (secondary growth)
Contains the apical meristem.
Apical bud:
Located at the conjecture between the peitole, or the leaf and the stem.\
Produces new
leaves or stems.
Axillary bud:
Area where leaves arise.
Nodes
Portion between the nodes.
Internodes
Also present in tropical species, and in mangroves
one of many raised pores in the stem of a woody plant that allows gas exchange between the atmosphere and the internal tissues.
Lenticels
More obvious in temperament species because they have distinct seasons.
scars are the scars remaining after the bud scales fall off.
scar remaining after the leaf falls off.
(two items)
Leaf Scar and Bud Scar.
Tropic seasons don’t have too much
distinction in terms of temperature changes so the scarring isn’t obvious.
true
Papaya tree: Has obvious leaf scars that are considered characteristics of the tree, but is not a woody dicot nor a tree
true
leaf primordia
groups of cells that will form into new leaves. These new leaves form near the top of the shoot and resemble knobby outgrowths or inverted cones.
giving rise to the epidermis.
Protoderm
giving rise to vascular tissues: the water-conducting Xylem and the food-condcuting Phloem (FOR STEMS).
Procambium
giving rise to ground tissues: Pith (center) and the Cortex (between the epidermis and phloem).
Ground meristem
Defined differences between stem tissues having defined functions.
Area of cell maturation
No cuticle
Root cap
Root hairs
Pericycle
Endodermis
Branches form internally from
the pericycle
Photosynthetic
Pith
Cuticle No cap Trichomes
No pericycle Endodermis rare
Branches form externally from lateral buds
Note: Some exceptions to these general differences exist.
Roots and stems difference with nodes
herbacious dicot
ROOTS
No nodes or internodes
STEMS
Nodes and internodes
Roots and stems difference with leaves and buds
herbacious dicot
ROOTS
No leaves or buds
STEMS
Leaves and buds
Roots and stems difference with pith
herbacious dicot
ROOTS
No pith
STEMS
pith
Roots and stems difference with cuticle
herbacious dicot
ROOTS
No cuticle
STEMS
cuticle
Roots and stems difference with pericycle
herbacious dicot
ROOTS
pericycle
STEMS
no pericycle
Roots and stems difference with endodermis
herbacious dicot
ROOTS
endodermis
STEMS
endodermis rare
Vascular bundles in monocots and dicots
Dicots: Larger vascular bundles, more organized. circular
Monocots: Smaller vascular bundles, scattered.
Ground tissue in monocots and dicots
Dicot: Central pith and cortex.
Monocot: Cannot distinguish cortex from the pith.
epidermis is covered by water conserving ___
cuticle
no vascular cambium in monocot stems
true
herbacious dicot does not have an active vascular cambium
true
elongation occurs at the shoot apical meristems and root apical meristems
true
widening occurs at the secondary meristems
true
xylem that grows in the spring, paler and more spongy
spring wood
xylem that grows in the summer, darker and more compact
summer wood
how palm trees / coconut increase their vascular tissues and fiber cells in the stem.
They increase their vascular tissues and fiber cells in the stem.
anomalous secondary growth
secondary growth is produced by _______ which produces secondary xylem (wood) to the inside and secondary phloem (inner bark) to the outside.
vascular cambium
Thin, somewhere between the blue-green and maroon cells.
Pushes the phloem outside the cell.
Secondary xylem tissues are pushing the primary xylem tissues to the center of the stem.
Vascular cambium:
provides structural support but no
longer transports water
xylem
Heartwood
layer transports water to other parts of the tree
Sapwood
A lateral meristem that produces cork parenchyma to the inside and cork cells to the outside.
CORK CAMBIUM
Cork cambium and the tissues it produces make up the outer _____ of a woody
plant.
secondary phloem and periderm
Arises near the stem’s surface.
bark
The secondary xylem nearest the center is the oldest; this layer has a large diameter of xylem vessels.
Spring; has abundant water supply and plants tend
to exhibit rapid growth→ tend to have larger plant vessels.
Earlywood “Springwood”
Summer, water supply is limited and plant growth slows down → produces smaller plant vessel elements.
Latewood “Summerwood”
Autumn and Winter. Almost no plant growth; plants are dormant and stop producing leaves.
We can track the change in season for temperate species.
true
Central part; Older xylem vessels, no longer functional. Most of the secondary products are deposited in the hardwood. Heavily lignified and darker in color.
Stronger and durable. Can survive hollow or without sapwood.
Heartwood:
Functional part of the xylem. Younger xylem vessels that undergo functions to transport water and nutrients.
sapwood
trees won’t survive if there is no sapwood or inner bark (phloem) because won’t be able to conduct metabolic processes.
true
Unsuberized cells beneath the stomata.
Permit gas exchange to continue in older stems.
Produced along with cork cells, by the cork cambium.
Varies in shape.
LENTICELS
LENTICELS are Also found in:
Surfaces of leaves in certain taxa (genus and species)
Surfaces of fruits, e.g. apples, pears, plums.
On potato tubers and sweet potato roots.
Economic Importance of Stem
Food
Medicine
Paper
Resin
Fuel
Lumber
is a woody swelling of the root crown possessed by some plants as a protection against destruction of the plant stem, such as by fire.
Lignotubers
young plant of bananas
Suckers
trichomes can be Multi-seriate/multi-cellular or UNICELLULAR in stems, branching
true
A short, thickened underground stem specialized for food storage and asexual reproduction
vertically oriented
Example: crocus
Corm
The thickened end of a rhizome that is fleshy and enlarged for food storage Example: white potato
Tuber
A rounded, fleshy underground bud that consists of a short stem with fleshy leaves Example: onion
Bulb
An aerial horizontal stem with long internodes; often forms buds that develop into separate plants.
Asexual reproduction; clone of the motherplant.
Stolons:
Stems that twine around, supports, and aid in climbing.
Tendrils
Flattened, photosynthetic stems that resemble leaves.
Extreme conditions → Extreme adaptations with the stem performing the functions of the leaves.
Cladophylls
Fibers from which plant are are extracted from the stem and tured into different textiles.
ramie
High-quality charcoal from mangrove species, but these is already banned because preserving thrmprovide a better benefit for the environment and the ecosystem.
Mangrove charcoals:
Staple food in the Pacific and in some places of Africa.
Colocaisa esculenta (Taro or gabi):
Powder is extracted from the plant of cinnamomum verum. Wasabi: Extracted from the storage stem of the eutrema japonicum.
Cinnamon:
Cork of the plant makes the wine bottle corks.
Quercus suber:
Harvesting cork should be done carefully because cork cambium should not be harvested (the one responsible for making more cork), as well as the inner bark (secondary phloem), otherwise the tree will die.
plant Used to polish the bones. The varnish, not the colors.
Toxicodendron vernicifluum
plant that make laquer
Rubber tree (hevea brasiliensis)
Very previous resin extracted from Agathis philippinensis (endangered) and belongs to the indigenous people.
Manila copal
Another important resin extracted from canarium luzonicum. Relative of the pili nut tree. Also used in cosmetics.
Elemi resin
