Chapter 7: Leaves Flashcards
a flattened, usually photosynthetic structure arranged in various ways on a stem
leaf
an organ or structure at its earliest stage of development
-Origin of leaves
primordial
the stalk of a leaf
petiole
the conspicuous flattened part of a leaf or seaweed
blade
without petiole or pedicel; attached directly by the base
sessile
when a plant is shedding its leaves annually
deciduous
a leaf with the blade undivided into leaflets
simple leaf
a leaf whose blade is divided into distinct leaflets
compound leaf
having leaflets or veins on both sides of a common axis to which they are attached
pinnately compound
the axis of pinnately compound leaf or frond extending between the lowermost leaflets or pinnae and the terminal leaflet or pinna (corresponds with the midrib of a simple leaf)
rachis
heaving leaflets or principal veins radiating out from a common point
palmately compound
a minute pore or opening in the epidermis of leaves, herbaceous stems, and the sporophytes of hornworts; it is flanked by two guard cells that regulate its opening and closing and thus regulate gas exchange and transpiration
stoma (pl. stomata)
What are some functions of leaves?
respiration, transpiration, and photosynthesis
loss of water in vapor form; most takes place through the stomata
transpiration
the exudation from leaves of water in liquid form due to root pressure
guttation
region of a stem where one or more leaves are attached
node
a stem region between nodes
internode
placed at different heights or distance from one another, as leaves can be arranged on a stem
alternate
placed at same heights or distance from one another, as leaves can be arranged on a stem
opposite
having three or more leaves or other structures at a node, as leaves can be arranged on a stem
whorled
of vein arrangements, having leaflets or veins on both sides of a common axis to which they are attached
pinnately veined
primary region of vascular tissue, usually spanning the center of a leaf
midvein
the central (main) vein of a pinnately veined leaf or leaflet
midrib
of vein arrangements, having leaflets or principal veins radiating out from a common point
palmately veined
a small body of variable shape and size that may secrete certain substances but that also may be functionless
-Occur in the form of depressions, protuberances, or appendages either directly on the leaf surface or on the ends of hairs
gland
one of a pair of specialized cells surrounding a stoma
-Regulate gas exchange between the interior of the leaf and the atmosphere, and regulate evaporation of the water entering the plant at the roots
guard cell
parenchyma tissue between the upper and lower epidermis of a leaf
mesophyll
consists of compactly stacked, barrel-shaped, or post-shaped parenchyma cells that are commonly in two rows; may contain more than 80% of the leaf’s chloroplasts
palisade mesophyll
consists of loosely arranged parenchyma cells with abundant air spaces between them; also has numerous chloroplasts
spongy mesophyll
a term applied to any of the vascular bundles that form a branching network within leaves
vein
the parenchyma and/or sclerenchyma cells surrounding a vascular bundle
bundle sheath
a layer of cells immediately beneath the epidermis and distinct from the parenchyma cells of the cortex in certain plants
hypodermis
a slender structure that coils on contact with a support of suitable diameter; it usually is modified leaf or leaflet and aids the plant in climbing
tendril
a relatively strong, sharp-pointed, woody structure usually located on a stem; it is usually a modified leaf or stipule
spine
a pointed specialized stem
thorn
a pointed outgrowth from an epidermis or cortex beneath the epidermis
prickle
a structure that is usually leaflike and modified in size, shape, or color
bract
the separation of leaves, flowers, and fruits from plants after the formation of an abscission zone at the base of their petioles, peduncles, and pedicels
abscission
What do humans use leaves for?
shade, food, spices and flavorings, dyes, fuel, oil, drugs, beverages, insecticides, and waxes
What leaf margin is this an example of?
plant: pothos
entire leaf margin
What leaf margin is this an example of?
plant: mulberry
serrate leaf margin
What leaf margin is this an example of?
doubly serrate leaf margin
What leaf margin is this an example of?
pinnately lobed leaf margin
What leaf margin is this an example of?
palmately lobed leaf margin
What type of cotyledon is this leaf?
dicot leaf
What type of cotyledon is this leaf?
monocot leaf
