Lab Ex 32 Vegetative Structure of Vascular Plants Flashcards
Secondary roots
primary root produces numerous these and forms a root system that absorbs water and minerals, anchors the plant, and stores food
Radicle
young primary root that emerges from the seed and grows down
Taproot system
has a large main root and smaller secondary roots branching from it (ex. carrot)
fibrous root system
primary and secondary roots are similar in size (ex. roots of many grasses)
Primary growth
apical meristems of roots and all primary tissues contributes to this
Apical meristems
primary growth of roots and all primary tissues formed by these
Secondary growth
refers to growth in girth resulting from nonapical meristems
Parts of a root
root cap, root apical meristem, zone of elongation, zone of maturation
Root hairs
in the zone of maturation; outgrowths of epidermal cells; short-lived; increase the surface area of the root
Epidermis
outer layer of root cells
Cortex
layer just inside the epidermis; cells contain numerous amyloplasts
Amyloplasts
starch-containing plastids
Endodermis
inner layer of the cortex; regulates water flow to the vascular tissue in the center of the root
Pericycle
immediately inside the endoderm; can become meristematic and produce secondary roots
Vascular Cylinder
Fluid-conducting cylinder composed of xylem and phloem
Xylem
transports water and minerals
Phloem
transports most organic compounds in the plant
Tracheids & vessels
water-conducting cells in the xylem of angiosperms; dead; hollow at maturity; long, spindle-shaped cells with thin areas called pits where the cell walls of adjacent cells overlap
Vessels
water-conducting cells in the xylem of angiosperms; stacks of cylindrical cells with thin or completely open end-walls; water moves through these in straight open tubes
Sieve cells & sieve tube members
conducting cells in phloem; alive at maturity; small, thin-walled, arranged in bundles that alternate with the poles of xylem
Lignin
stained by phloroglucinol; a molecule that strengthens xylary cell walls
Shoot apical meristem
dome-shaped, not covered by a cap; produces young leaves (leaf primordia) that attach to the stem at a node
Leaf primordia
young leaves that attach to the stem at a node; produced by the shoot apical meristem
Node
shoot apical meristem produces young leaves that attach to the stem at this point
Axillary bud
between the young leaf and the stem; forms a branch or flower
Terminal bud
at the stem tip; contains the apical meristem; surrounded by bud scales
Bud scales
surrounds the terminal bud at the stem tip
Leaf scars
from shed leaves; occur at regularly spaced nodes along the length of the stem
Internodes
portions of stems between the nodes
Vascular bundle scars
may be visible within the leaf scars
Bud scale scars
distance between clusters of these or from a cluster to the terminal bud indicates the length of terminal growth
Epidermis
covers the stem; coated with a waxy, waterproof substance (cutin)
Cutin
waxy, waterproof substance that coats the epidermis
Cortex (stem)
below the epidermis; stores food
Pith
in the center of the stem; stores food
Collenchyma
smaller, rectangular cells with unevenly thickened cell walls; support elongating regions of the plant
Sclerenchyma fibers
thick-walled cells just outside the phloem; function in support; in some plants, these are used to make linen, rope, and burlap
Dicots
flowering plants with 2 cotyledons (seed leaves)
Monocot
flowering plants with only 1 cotyledon
Vascular cambium
secondary meristem that produces secondary growth (growth in girth); cylindrical, produces secondary xylem to its inside and secondary phloem to its outside
Periderm
ruptured epidermis is replaced by this tissue; functions to minimize water loss; consists of cork cells produced by another secondary meristem (cork cambium)
Cork cambium
produces cork cells to the outside and cork parenchyma to the inside; stain red because of the presence of suberin (water-impermeable lipid)
Lenticels
gas exchange through peridermal tissues occurs through these structures
Leaf parts
blade and petiole
Petiole
attaches the leaf blade to the stem
Simple leaves
have 1 blade connected to the petiole
Compound leaves
have several leaflets sharing one petiole
Palmate leaflets
compound leaf with leaflets that arise from a central area
Pinnate leaflets
compound leaf with leaflets that arise in rows along a central midline
Venation
arrangement of veins
Parallel veins
veins that extend the entire length of the leaf with little or no cross-linking
Pinnately veined leaves
leaves with one major vein (midrib) from which other veins branch
Palmately veined leaves
leaves with several veins each having branches
Phyllotaxis
arrangement of leaves on a stem
Opposite phyllotaxis
refers to 2 leaves per node located on opposite sides of the stem
Whorled phyllotaxis
refers to more than 2 leaves per node
Alternate phyllotaxis
refers to 1 leaf per node, with leaves appearing first on one side of the stem and then on another
Palisade mesophyll
just below the upper epidermis; closely packed cells; contain about 50 chloroplasts per cell
Stomata
epidermis contains these pores, each surrounded by 2 guard cells
Spongy mesophyll
cells with numerous intercellular spaces; below the palisade layers
