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Cells produced by stem meristem become what?
shoot sytems with branches and leaves
Woody twigs consists of what?
An axis with attached leaves
Area of stem where leaves are attached
Nodes can be
- *alternate or spiral
- *opposite= attached in pairs
- *whorled= in groups of 3 or more
Stem region between nodes
angle between petiole and stem
where are the axillary buds located?
in the axil
Axillary buds will become what?
branches or flowers in flowering plants
What do bud scales do?
protect the buds
Where are the terminal buds located?
at twig tip
What makes the twig longer?
What determines the age of an twig?
bud scale scars
paird, often leaflike appendages at base of a leaf
What type of tress lose all of their leaves annually?
- deciduous treees and shrubs
- --after leaves fall, they have axillary buds with leaf scars below
What are bundle scars?
they mark food and water conducting tissue within leaf scars
Where is the apical meristem located?
at the stem tip
Whats does the apical meristem do?
- *Contributes to increase in stem lenght
- *Dormant before growing seasons begin
- *Are protected by bud scales and by leaf primordia
What is leaf primordia?
tiny embryonic leaves that develop into mature leaves
Apical meristems cells form what 3 primary meristems?
- Ground Meristem
What is protoderm?
gives rise to the epidermis
What is procambium?
produces the xylem and pholem
What is ground meristem?
produces the pith and cortex, both composed of parenchyma cells
Leaf primordia and bud pimordia develop into what?
mature leaves and buds
What are traces?
- *strand of xylem and pholem
- *traces branch offf from cylinder of xylem and pholem, and enter leaf or bud
Each traces leaves what?
leaves a gap filled with parenchyma in the cylinder of vascualr tissue, forming leaf gap or bud gap
Narrow band of cells between the primary xylem and primary pholem may become what?
Cells produced by the vascular cambium become what?
components of secondary xylem towards center and secondary pholem towards surface
In plants the cork cambim produces what type of cells?
- corks cells with suberin and phelloderm cells
- *whose function is to reduce the watter loss and protect stem against injury
What are lenticels?
parenchyma cells in cork for exchange of gases
What is stele?
central cylinder of primary xylem, primary pholem and pith (if present)
What is prostele?
- solid core, pholem surrounds xylem
- *in primitive seed plants, whisk ferns, club mosses and ferns
What is sipphonosteles?
- tubular with pith in center
- *common in ferns
What is eusteles?
- discrete vascular bundles
- *in flowering plants and conifers
seed leaves attached to embryonic stems
flowering plants that develop from seeds having two cotyledons
flowering plants that develop from seeds with a single cotyledon
What are annuals?
- plants that die after going from seed to maturity within one growing season
- *usually green, herbaceous plants
- *most monocots are annuals, but many dicots are to
- *tissues largely primary
Herbaceous discots have discrete vascular bundles arrange how?
in a cylinder
Where does the vascular cambium arise?
between the primary xylem and primary pholem
Wood has what type of xylem?
Some difference in wood are?
*vascular cambium and cork cambium are active all year
What is an annual ring?
one years growth of xylem
Vascular rays consist of what?
- parenchyma cells that function in lateral conduction of nutrients and
What are xylem rays?
part of ray within xylem
What are pholem rays?
part of ray through pholem
What are tyloses?
- protrusions of adjacent parenchyma cells into conducting cells of xylem
- *they prevent conduction of water
- *resins, gums, and tannins accumulate, and darken wood, forming heartwood
What is heartwood?
older, darker wood in cneter
What is sapwood?
lighter, still functioning xylem closet to cambium
What is softwood?
- wood of conifers
- *no fibers or vessel elements
What is hard wood?
wood of dicot trees
What are resin canals?
- tubelike canals scattered throughout xylem and other tissues
- *they are lined with specialized cells that secrete resin
- *common in conifers
- *in some tropical flowering plants
What is bark?
- tissues outside of the vascular cambium
- *mature bark may consist of alternating layers of crushed pholem and cork
What are laticifers?
- Ducts found mostly in phloem that have latex secreting cells
- *example: rubber, chicle (chewing gum), and ,morphine
Monocots stems have neither of what?
vasuclar cambium nor a cork cambium
In monocot stems where are the primary xylem and phloem found?
in discrete vascular bundles scattered throughout the stem
In monocots vascular bundles are typically what?
- *2 large vessels with several small vessels
- *first formed xylem cells stretch and collapse, which leaves irregualarly shaped air spaces
- *pholem consists of sieve tubes and companion cells
- *vascular bundles surrounded by sheath and sclerenchyma cells
What is rhizomes?
- a specialized horizontal stems that grow below ground and have long to short internodes
- *some grasses and ferns
What are runners?
- a specialized horizontal stem that grows above ground and have long inrernodes
What are stolons?
- a specialized stem the is produced beneath the surface of the ground and tend to grow in differnt directions
What are tubers?
- sowllen, fleshy underground specialized stems
- * they store food
What are the eyes on a potato called?
What are bulbs?
- large buds surrounded by numerous fleshy leaves, with a small stem at lower end
- *they store food
- *ex: onions, lilies, hyacinths, tulips
What are corms?
- they resemble bulbs, but composed almost entirely of stem of stem tissue, with papery leaves
- *they store food
- *crocus and gladiolus
What are cladophylls/
- flattened leaf like stems
- *ex: greenbriars, some orchids, prickly pear cactus
In living trees where does half of the wood weight come from?
50% of the wood weight come from water content
What is the dry part of the wood composed of?
about 60-75% cellulose and about 15-25% ligin
What is density?
weight per unit volume
What is durablility/
- ability to withstand decay
- *ex: tannins and oils repel decay organisms
What is radially cut (quarter sawed)?
boards show annual rings in side view
What is tangentially cut (plain sawed or slab cut)?
- boards are cut perpendicular to rays
- *shows annual rings as irregular band of light and dark streaks
What are knots?
bases of lost braches covered by new annual rings produced by the cambium
What is veneer?
thin sheet of desirable wood glued to cheaper lumber
What is pulp?
- the second most widespread use of wood
- *ex: paper, synthetic fibers, plastics, and linoleum