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Cells produced by stem meristem become what?
shoot sytems with branches and leaves
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Woody twigs consists of what?
An axis with attached leaves
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Define node?
Area of stem where leaves are attached
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Nodes can be
- *alternate or spiral
- *opposite= attached in pairs
- *whorled= in groups of 3 or more
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Define Internode?
Stem region between nodes
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Define Axil?
angle between petiole and stem
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where are the axillary buds located?
in the axil
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Axillary buds will become what?
branches or flowers in flowering plants
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What do bud scales do?
protect the buds
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Where are the terminal buds located?
at twig tip
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What makes the twig longer?
growth
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What determines the age of an twig?
bud scale scars
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Define stipules?
paird, often leaflike appendages at base of a leaf
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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
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What are bundle scars?
they mark food and water conducting tissue within leaf scars
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Where is the apical meristem located?
at the stem tip
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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
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What is leaf primordia?
tiny embryonic leaves that develop into mature leaves
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Apical meristems cells form what 3 primary meristems?
- Protoderm
- Procambium
- Ground Meristem
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What is protoderm?
gives rise to the epidermis
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What is procambium?
produces the xylem and pholem
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What is ground meristem?
produces the pith and cortex, both composed of parenchyma cells
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Leaf primordia and bud pimordia develop into what?
mature leaves and buds
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What are traces?
- *strand of xylem and pholem
- *traces branch offf from cylinder of xylem and pholem, and enter leaf or bud
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Each traces leaves what?
leaves a gap filled with parenchyma in the cylinder of vascualr tissue, forming leaf gap or bud gap
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Narrow band of cells between the primary xylem and primary pholem may become what?
vasuclar cambium
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Cells produced by the vascular cambium become what?
components of secondary xylem towards center and secondary pholem towards surface
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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
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What are lenticels?
parenchyma cells in cork for exchange of gases
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What is stele?
central cylinder of primary xylem, primary pholem and pith (if present)
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What is prostele?
- solid core, pholem surrounds xylem
- *in primitive seed plants, whisk ferns, club mosses and ferns
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What is sipphonosteles?
- tubular with pith in center
- *common in ferns
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What is eusteles?
- discrete vascular bundles
- *in flowering plants and conifers
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Define cotyledons?
seed leaves attached to embryonic stems
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Define dicotyledons?
flowering plants that develop from seeds having two cotyledons
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Define Monoctyledons?
flowering plants that develop from seeds with a single cotyledon
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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
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Herbaceous discots have discrete vascular bundles arrange how?
in a cylinder
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Where does the vascular cambium arise?
between the primary xylem and primary pholem
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Wood has what type of xylem?
secondary xylem
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Some difference in wood are?
*vascular cambium and cork cambium are active all year
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What is an annual ring?
one years growth of xylem
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Vascular rays consist of what?
- parenchyma cells that function in lateral conduction of nutrients and
- water
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What are xylem rays?
part of ray within xylem
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What are pholem rays?
part of ray through pholem
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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
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What is heartwood?
older, darker wood in cneter
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What is sapwood?
lighter, still functioning xylem closet to cambium
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What is softwood?
- wood of conifers
- *no fibers or vessel elements
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What is hard wood?
wood of dicot trees
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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
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What is bark?
- tissues outside of the vascular cambium
- *mature bark may consist of alternating layers of crushed pholem and cork
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What are laticifers?
- Ducts found mostly in phloem that have latex secreting cells
- *example: rubber, chicle (chewing gum), and ,morphine
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Monocots stems have neither of what?
vasuclar cambium nor a cork cambium
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In monocot stems where are the primary xylem and phloem found?
in discrete vascular bundles scattered throughout the stem
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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
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What is rhizomes?
- a specialized horizontal stems that grow below ground and have long to short internodes
- *some grasses and ferns
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What are runners?
- a specialized horizontal stem that grows above ground and have long inrernodes
- *strawberries
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What are stolons?
- a specialized stem the is produced beneath the surface of the ground and tend to grow in differnt directions
- *potato
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What are tubers?
- sowllen, fleshy underground specialized stems
- * they store food
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What are the eyes on a potato called?
nodes
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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
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What are corms?
- they resemble bulbs, but composed almost entirely of stem of stem tissue, with papery leaves
- *they store food
- *crocus and gladiolus
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What are cladophylls/
- flattened leaf like stems
- *ex: greenbriars, some orchids, prickly pear cactus
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In living trees where does half of the wood weight come from?
50% of the wood weight come from water content
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What is the dry part of the wood composed of?
about 60-75% cellulose and about 15-25% ligin
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What is density?
weight per unit volume
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What is durablility/
- ability to withstand decay
- *ex: tannins and oils repel decay organisms
-
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What is radially cut (quarter sawed)?
boards show annual rings in side view
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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
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What are knots?
bases of lost braches covered by new annual rings produced by the cambium
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What is veneer?
thin sheet of desirable wood glued to cheaper lumber
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What is pulp?
- the second most widespread use of wood
- *ex: paper, synthetic fibers, plastics, and linoleum
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