Lab 4 Flashcards
cotyledon
seed leaf found within the embryo of a seed; stores nutrients and is the first to appear during germination, providing nourishment to the developing seedling
leaf
principal organ of photosynthesis and transpiration in vascular plants, typically flattened and thin, and attached to a stem by a petiole
leaf blade/leaf lamina
expanded and flat - to maximize light capture - portion of the leaf where photosynthesis occurs
petiole
stalk that attaches the leaf blade to the stem; provides support and allows the leaf blade to orient itself optimally for photosynthesis
leaf base
part of the leaf where the petiole attaches to the stem; has various shapes and structures, including stipules
stipule
small, often leaf-like appendages found at the base of the petiole in some plants; can be membranous or leaf-like and serve various functions, including protection and water conservation
simple leaf
consists of a single, undivided blade attached to the petiole; ex. oak and maple leaves
leaf sheath
tubular structure that partially or wholly surrounds the stem where a leaf attaches; common in grasses and some monocots, providing additional support and protection
leaf adaxial side
upper surface, facing towards the stem or main axis of the plant; receives more direct sunlight and is typically more photosynthetically active than the abaxial side
leaf abaxial side
lower surface, facing away from the stem or main axis of the plant; less exposed to direct sunlight and may have specialized features like stomata and trichomes
compound leaf
consists of multiple leaflets attached to a common petiole or rachis; each leaflet may resemble a simple leaf, but they are not directly attached to the stem
rachis
central axis or main vein of a compound leaf, to which leaflets are attached; provides support and structure to the leaflet arrangement
leaflet
one of the individual segments of a compound leaf; may be attached to the rachis or petiole, depending on the leaf’s overall structure
node
point on a stem where leaves, buds, or branching structures originate; swollen area of the stem with actively dividing cells
internode
portion of a stem between two adjacent nodes; may vary in length and thickness depending on the plant species and growth conditions
parallel venation
type of leaf venation where the veins run roughly parallel to each other from the base to the tip of the leaf; monocotyledonous plants, such as grasses and lilies
pinnate venation
type of leaf venation where one main vein extends from the base to the tip of the leaf, with smaller veins branching off it; dicotyledonous plants
palmate venation
venation in leaves where several main veins originate from a single point at the base of the leaf, resembling the structure of a hand with outstretched fingers
phyllotaxis
arrangement of leaves on a stem, including alternate, opposite, and whorled arrangements
heterophylly
phenomenon in plants where leaves of different shapes or forms are produced on the same plant or under different environmental conditions
main vein
primary vein or midrib running through the center of a leaf
epidermis
outermost layer of cells covering the surfaces of leaves, stems, and roots in plants, providing protection and regulating gas exchange
glandular hair
hair-like structures found on the surface of leaves or other plant parts, often containing glands that secrete substances such as oils or resins
simple hair
hair-like outgrowths of epidermal cells on the surface of plant organs, providing protection against herbivores and reducing water loss
stomatal complex
structure consisting of a stomate and surrounding guard cells, regulating gas exchange and transpiration in plants
stoma/pore
microscopic opening in the epidermis of leaves and stems, surrounded by two guard cells, through which gas exchange and water vapor transpiration occur
guard cell
specialized cells surrounding the stomatal pore, which regulate its opening and closing in response to environmental stimuli
substomatal cavity
space beneath a stomatal pore, facilitating gas exchange between the leaf interior and the external environment
bulliform cells
large, specialized cells found in the epidermis of monocots, involved in leaf rolling and folding in response to water stress
hypostomatic leaf
leaf with stomata present only on the abaxial surface
mesophyll
internal tissue of a leaf, located between the upper and lower epidermis, where photosynthesis occurs
pallisade parenchyma
layer of elongated parenchyma cells found beneath the upper epidermis in many plant leaves, involved in photosynthesis
spongy parenchyma
layer of loosely arranged parenchyma cells found beneath the palisade parenchyma in many plant leaves, involved in gas exchange and storage
idioblast
specialized plant cells that differ from surrounding cells in structure and function, often involved in storage or secretion
druse
type of crystal aggregate found in the cells of some plants, often composed of calcium oxalate
bundle sheath
layer of cells surrounding the vascular bundles in the leaves of C4 plants, involved in photosynthesis and carbon fixation
bundle sheath extension
extension of the bundle sheath cells into the mesophyll, found in certain types of C4 plants, facilitating the uptake of CO2 for photosynthesis
transfer cell
specialized plant cell with an increased surface area, involved in the transfer of nutrients and other molecules between cells or tissues
phloem
vascular tissue responsible for transporting organic nutrients, primarily sugars, from photosynthetic tissues to other parts of the plant
xylem
vascular tissue responsible for transporting water and minerals from the roots to the rest of the plant; provides structural support
fascicular cambium
lateral meristem found within vascular bundles in plants, responsible for producing secondary xylem and phloem during secondary growth; differentiates from procambium located between the primary xylem and the primary phloem of individual vascular bundles
lacunar collenchyma
type of collenchyma tissue with intercellular spaces, providing support and flexibility to stems and other plant parts
