LEAF STRUCTURE AND FUNCTION Flashcards
the thin, transparent layer of wax called ____ that covers the leaf surface is a compromise between the needs to optimize photosynthesis and to minimize water loss
CUTICLE
many plants can be identified by their _____ alone
leaves
leaves may be ______ (single blade) or ________ (having a blade divided into two or more leaflets)
SIMPLE; COMPOUND
leaves grow from ___________
LEAF PRIMORDIUM
leaves are arranged on a stem in one of three ways:
ALTERNATE,
OPPOSITE, or
WHORLED
leaf blades may have these two kinds of venation patterns
PARALLEL VENATION or
NETTED VENATION
in leaves, most cells in upper and lower epidermis lack _________ and are relatively ___________ that allows light to reach the mesophyll cells
chloroplasts; transparent
these cells secrete a waxy cuticle that reduces water loss from exterior walls
EPIDERMAL CELLS
many leaves are covered with these that help reduce water loss, secrete stinging irritants to deter herbivores, or excrete excess salts
TRICHROMES
leaf epidermis contains ________ for gas exchange
STOMATA
each stoma is flanked by two _______, which open and close the stoma
guard cells
guard cells are associated with these cells that provide a reservoir of water and ions
(special) SUBSIDIARY CELLS
photosynthetic ground tissue of the leaf sandwiched between the upper and lower epidermis
LEAF MESOPHYLL
these are parenchyma cells with chloroplasts, loosely arranged, with many air spaced between them that facilitate gas exchange
MESOPHYLL CELLS
TWO SUBLAYERS OF MESOPHYLL
PALISADE MESOPHYLL
SPONGY MESOPHYLL
differentiate palisade from spongy mesophyll
palisade mesophyll are columnar cells in the UPPER layer and are specialized for light capture (also can be organized into one, two, three or more layers)
spongy mesophyll are irregularly arranged cells in the LOWER layer and loosely packed, allowing diffusion of gases within the leaf, particularly CO2
_____________ of a leaf extend through the mesophyll – branching is extensive; no mesophyll cell is more than two or three cells away from one of these
veins (vascular bundles)
each vein of a leaf contains these two
xylem and phloem
conducts water and dissolved minerals, usually in the _____ part of a vein
XYLEM; upper
conducts dissolved sugars, usually in the ____ part of a vein
PHLOEM; lower
one or more layers of nonvascular cells surround the larger veins and make up the _________
BUNDLE SHEATH
bundle sheaths may have _____________ that extend through the mesophyll from the upper to lower epidermis
BUNDLE SHEATH EXTENSIONS
bundle sheath extensions may be composed of which types of simple tissue cells?
parenchyma, collenchyma, or sclerenchyma cells
broad, flattened blade with a petiole
eudicot or monocot leaf?
EUDICOT LEAF
netted venation
eudicot or monocot leaf?
EUDICOT LEAF
the guard cells are shaped like kidney beans
eudicot or monocot leaf?
EUDICOT LEAF
narrow blade; base of the leaf wraps around the stem
eudicot or monocot leaf?
MONOCOT LEAF
parallel venation
eudicot or monocot leaf?
MONOCOT LEAF
some of the guard cells are shaped like dumbbells
eudicot or monocot leaf?
MONOCOT LEAF
guard cells are associated with epidermal cells called what
SUBSIDIARY CELLS
guard cells of eudicots and many monocots are _____-SHAPED
BEAN-SHAPED
some _______ guard cells are narrow in the center and thicker at each end
monocot
these supply photosynthetic tissue with water and minerals (from roots, through xylem) and carry (in phloem) dissolved sugar produced during photosynthesis to all parts of the plant
VEINS
a stalk that attaches a leaf to the plant stem
PETIOLE
leaves of water lilies have _____ and ______ in the mesophyll for buoyancy – submerged parts have an internal system of _______ for O2
long petioles and large air spaces;
air ducts
leaves of most conifers are _______-shaped with a _________ cuticle and ______ stomata that permit gas exchange while minimizing water loss to help them survive ________-
needle; thick, waxy; sunken; dry winters
