Lab Terms Flashcards
anatomy
the study of the internal structure of an organism
morphology
the study of the external form of an organism
axillary (lateral) bud
a bud (a short stem with a shoot apical meristem and small leaves) produced by an axillary meristem in the axil of a leaf; can grow into a branch
axillary meristem
a mass of undifferentiated cells capable of undergoing mitosis; found on a stem in the axil of the leaf where it attaches to the stem
cotyledon
part of a plant embryo within a seed; a seed leaf, swollen with food absorbed from the endosperm to provide nutrition to the embryo during germination ; may be pulled by the germinated seedling above the soil and become photosynthetic
internode
the region of a plant stem between two adjacent nodes
leaf blade (lamina)
the thin, flat part of a leaf
midrib
the large, central vein of a leafnode\
node
the region of a plant stem where leaves attach
petiole
part of a leaf; the stalk which attaches the leaf blade to the stem at a node
shoot apex (terminal bud)
the bud at the top of a stem; consists of the shoot apical meristem and small primordial leaves around the tip of the stem where the internodes are not yet elongated
shoot apical meristem (SAM)
a small mass of undifferentiated cells capable of rapid cell division to produce new cells for the primary growth of the stem; found at the tip of each shoot
trichome
a unicellular or multicellular outgrowth of the epidermis on the aerial parts of the plant, (stems, leaves, or flowers); can be unbranched or branched, and have a variety of shapes; can have many functions, often involved with protection of the plant - discourage herbivores, prevent frost from getting at the epidermis, reduce wind flow to reduce transpirational water loss, shade the plant in very hot dry climates, etc. Some secrete chemicals for a variety of functions
primary root
the root which develops from the radicle of the embryo within the seed
root apical meristem (RAM)
a small mass of undifferentiated cells capable of rapid cell division to produce new cells for the primary growth of the root; found at the tip of each root just above the protective root cap
root cap
a sheath of parenchyma cells produced by the root apical meristem to protect the RAM from abrasion as the root grows through the soil; the oldest cells are continually sloughed off and replaced by new cells from the RAM
secondary (lateral) root
root that branches from the primary root or other secondary roots; produced from lateral root primordia at the pericycle layer of the root’s stele
tap root system
the roots of a plant where there is a persistent, well developed primary root; typical of eudicot plants
trichoblast (root hair)
lateral extension of and an epidermal cell on a root; it increases surface area for the absorption of water and nutrients
cladode
flattened, photosynthetic stems, such as those of some cacti; in cacti, these stems also function in water storage
corm
a short underground stem specialized for food storage (starch), which is enclosed by papery leaves
rhizome
- a horizontal stem which is underground
- has axillary buds at nodes and often produces adventitious roots along its length
- functions in asexual reproduction
- helps the plant survive extreme heat, cold, or dryness when the aerial portions of the plant die
runner (stolon)
an aboveground, horizontal stem that functions in asexual reproduction
tendril
a stem modified to twine around other plants or objects to help support the plant
thorn
a short, sharp stem for protection from herbivores
tuber
the tip of a rhizome, swollen with carbohydrates that functions in food storage and asexual reproduction
cell wall
a thick, rigid coat formed outside of the plasma membrane of a plant cell that is composed mainly of cellulose and provides support to the cell and the plant
central vacuole
a large organelle within a mature plant cell that consists of cell sap within the tonoplast
tonoplast
the membrane that forms the outer boundary of the central vacuole of a plant cell
chloroplast
an organelle (plastid) within a plant cell which contains pigments such as chlorophyll and is responsible for photosynthesis
dermal tissue system
a layer of protective tissue which covers the entire surface of the plant ; consists of the epidermis, trichomes, and trichoblasts and is produced by the protoderm. Functions to protect from water loss via a secreted cuticle. Epidermal cells can also be specialized to facilitate gas exchange, for chemical signaling, or water absorption
epidermis
the outermost cell layer of a plant; composed of pavement epidermal cells and guard cells in leaves and stem, typically one cell thick and functions mainly in prevention of water loss
trichome
a unicellular or multicellular outgrowth of the epidermis on stems, leaves, or flowers; can function in the protection of the plant by discouraging herbivores, protecting the plant from extreme temps, secreting materials to the plant surface, etc
vascular tissue system
the cells and tissues associated with transport within the plant body; consists of xylem and phloem tissue and is produced by the procambium
bundle sheath
a layer or layers of cells enclosing a vascular bundle, consisting of parenchyma cells or sclerenchyma fibers or layers of both
vascular bundle
a strand of primary phloem and primary xylem often enclosed by a bundle sheath
xylem
tissue consisting of vessel elements and/or tracheids, xylem parenchyma, and xylem fibres; when mature and functional, the tracheary elements are dead with thick, lignified secondary walls and function in the transport of water and dissolved minerals within the plant body
protoxylem
the first primary xylem cells produced in plant tissue; often matured before the plant rapidly elongates and are sometimes damaged as a result
protoxylem lacuna (cavity)
a cavity formed in the area of the protoxylem, where the cells have been stretched and damaged by the elongation of the plant, leaving a cavity protoxylem cells used to be
metaxylem
the primary xylem cells that are produced after the protoxylem when that part of the plant is no longer elongating
tracheid
a long, slender, tapered xylem cell with a thick, lignified secondary wall; smaller diameter than vessel elements and often more angular; water is transported through the lumen of the dead cell
vessel element
a long, round xylem cell with a thick, lignified secondary wall and usually a fairly large diameter; joined end to end to form a vessel; water is transported through the lumen of the dead cell
xylem fiber
sclerenchyma fibers associated with the tracheary elements of xylem and are part of the vascular tissue system
xylem parenchyma
parenchyma cells associated with the tracheary elements of xylem and are part of the vascular tissue system
primary cell wall
a thick, rigid coat (mainly cellulose) formed outside of the plasma membrane of a plant cell; provides support to the cell and the plant
secondary cell wall
a cell wall laid down to the inside of the primary cell wall; often very thick and impregnated with lignin; functions in support
lignin
a complex, non-carbohydrate polymer which impregnates the cellulose of the secondary well; forms an impermeable layer
phloem
tissue consisting of sieve tube elements and companion cells; the cells are alive and thin-walled; function in transport of sugars and hormones
sieve tube element
an elongated, living phloem cell with no nucleus, ribosomes, or vacuoles at maturity, thus dependent on adjacent companion cells for proper functioning; multiple sieve tube elements are joined together, end to end, by sieve plates to form a sieve tube; transports sugar and hormones
companion cell
a specialized, elongate, nucleated phloem cell that is associated with (adjacent to) a sieve tube element; helps control the functioning of the sieve tube element
phloem fiber
sclerenchyma fibers associated with the specialized cell types of phloem and are part of the vascular tissue system
phloem parenchyma
parenchyma cells associated with the specialized cell types (sieve tube elements, companion cells) of phloem, and are part of the vascular tissue system
vascular cambium
a lateral meristem; a cylinder of meristematic cells around a stem or root between the primary phloem and primary xylem which will produce secondary vascular tissue (secondary phloem to the outside and secondary xylem to the inside)
ground tissue system
all tissues of the primary plant body that are not part of the dermal or vascular tissue systems; produced by the ground meristem and functions in photosynthesis, support, and storage for the plant
parenchyma
tissue consisting of relatively unspecialized living cells with thin walls, often loosely packed with intercellular spaces; function in storage and support
intercellular spaces
spaces between cells, most often found within photosynthetic tissue to facilitate gas exchange for the uptake of CO2 for photosynthesis
collenchyma
tissue composed of living cells with unevenly thickened primary cell walls; function in support where flexibility is important
sclerenchyma
tissue composed of cells with thick secondary walls impregnated with lignin, usually dead at maturity; function in support (can be part of the GTS or the VTS)
sclerenchyma fiber
an elongated, tapered sclerenchyma cell, usually with a thick secondary cell wall and dead at maturity; function is supportive or protective
sclereid
a thick-walled sclerenchyma cell with many pits; variable in form, often branched, but usually not elongated; they make up seed coats, nut shells, and the stones of fruit
cortex
the region of primary ground tissue of a stem or root located interior to the epidermis and external to the vascular tissue; can be parenchyma or layers of collenchyma, sclerenchyma, or parenchyma in any combination
pith
the region of primary ground tissue in the centre of a root or stem within the vascular cylinder; usually parenchyma, but can be sclerenchyma
cuticle
a thin, non-cellular layer secreted by the epidermis to prevent water loss from the plant body; composed of cutin, a waxy, water-repellant substance
pavement epidermal cell
an unspecialized cell of the dermal tissue system which closely interlocks with other epidermal cells to form a protective sheet of cells - the epidermis; secretes the cuticle to form a waxy, water-impervious protective layer on the outside
stoma (plural: stomata)
an opening in the epidermis, usually for a leaf, between two guard cells; allows CO2 to be absorbed for photosynthesis and transpiration to occur
guard cell
a cell of the dermal tissue system which works with a second guard cell to surround and control the opening and closing of a stoma to facilitate CO2 uptake and limit water loss
stomatal complex
refers to the pair of guard cells and the stoma they surround
non-secretory trichome
a unicellular or multicellular outgrowth of the epidermis on stems, leaves, or flowers; does not secrete chemicals but can protect the plant by discouraging herbivores, shading the plant and reducing water loss
secretory trichome
usually a multicellular outgrowth of the epidermis on leaves, stems, or flowers; secretes chemicals for a number of functions
dermal tissue system of coleus
epidermis, non-secretory trichomes, secretory trichomes
ground tissue system of coleus
cortex: consists of an outer layer of collenchyma (thicker in the corners of the stem) and an inner layer of parenchyma, both of which lie external to the vascular cambium
pith: consists entirely of parenchyma and lies internal to the vascular cambium
vascular tissue system of coleus
four large vascular bundles (one in each corner of the square stem) with some smaller vascular bundles along the sides; each bundle consists of primary phloem to the outside and primary xylem to the inside; the vascular bundles are joined by a thin layer, the vascular cambium
dermal tissue system of zea
epidermis, few or no trichomes
ground tissue system of zea
a thin layer of schlerenchyma next to the epidermis and a large area of parenchyma interspersed with vascular bundles (no cortex nor pith)
vascular tissue system of zea
vascular bundles scattered throughout the ground tissue of the stem; each “face” vascular bundle consists of primary phloem and primary xylem (with distinct areas of protoxylem and metaxylem) enclosed by a bundle sheath of schlerenchyma fibres; both tracheids and vessel elements present
angiosperm
flowering plants; a group of plants whose seeds are borne within a fruit (mature ripened ovary)
eudicotyledons
a subgroup of angiosperms where the plants have two cotyledons within their seeds; about 200 000 species
monocotyledons
a subgroup of angiosperms where the plants have one cotyledon within their seeds; about 60 000 species
