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105 terms

Plant Cells, Tissues and Organs

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tissue composed of only a single kind of cell
simple tissue
tissue composed of two or more different kinds of cells
complex tissue
plant tissues that are neither vascular nor dermal, fulfilling a variety of functions, such as storage, photosynthesis, and support
ground tissue system
the primary tissue of higher plants, composed of thin-walled cells and forming the greater part of leaves, roots, the pulp of fruit, and the pith of stems
parenchyma tissue
a relatively unspecialized plant cell type that carries out most of the metabolism, synthesizes and stores organic products, and develops into a more differentiated cell type
parenchyma cell
parenchyma cell specialized for transfer of water soluble material to or from a neighboring cell, usually a phloem sieve tube or a xylem tracheid
transfer cell
in plants, a thin layer of adhesive extracellular material, primarily pectins, found between the primary walls of adjacent young cells
middle lamella
a plant tissue that consists of living usually elongated cells with unevenly thickened walls and acts as support especially in areas of primary growth
collenchyma tissue
a flexible plant cell type that occurs in strands or cylinders that support young parts of the plant without restraining growth
collenchyma cell
a supporting tissue in plants consisting of dead cells with thick lignified walls
sclerenchyma tissue
a short, irregular sclerenchyma cell in nutshells and seed coats; sclereids are scattered throughout the parenchyma of some plants
sclereid
a lignified cell type that reinforces the xylem of angiosperms and functions in mechanical support; a slender, tapered sclerenchyma cell that usually occurs in bundles
fiber
a transport system formed by xylem and phloem throughout a vascular plant; xylem transports water and minerals; phloem transports sugars, the products of photosynthesis
vascular tissue system
vascular plant tissue consisting mainly of tubular dead cells that conduct most of the water and minerals upward from the roots to the rest of the plant
xylem tissue
the principal conductive cells of the xylem that conducts water and minerals from roots to the other parts of the plants
tracheary elements
a long, tapered water-conducting cell found in the xylem of nearly all vascular plants; functioning tracheids are no longer living
tracheid
a cavity in the wall of a plant cell where there is no secondary wall, as in fibers, tracheids, and vessels
pit
a short, wide water-conducting cell found in the xylem of most angiosperms and a few nonflowering vascular plants; dead at maturity, vessel elements are aligned end to end to form micropipes called vessels
vessel element
openings at both ends of the cell wall that connect the individual vessel elements
perforations
in plants, a relatively thin and flexible layer that surrounds the plasma membrane of a young cell
primary cell wall
in plant cells, a strong and durable matrix that is often deposited in several laminated layers around the plasma membrane and provides protection and support
secondary cell wall
vascular plant tissue consisting of living cells arranged into elongated tubes that transport sugar and other organic nutrients throughout the plant
phloem tissue
a type of plant cell occuring within the phloem; sieve elements combine to form a series of tubes (sieve tubes) connecting the leaves, shoots, and roots in a fine network
sieve element
an elongated, food-conducting cell in phloem characteristic of gymnosperms; sieve cells have pore through which nutrients frlow from cell to cell, but they have no sieve plats like the more specialized sieve-tube elements of angiosperms
sieve cell
a portion of a sieve element wall containing small diameter pores through which protoplasts of adjacent cells are connected
lateral sieve area
a living cell that conducts sugars and other organic nutrients in the phloem of angiosperms; also called a sieve-tube member; connected end to end, they form sieve tubes
sieve-tube element
an area in the wall of a sieve-tube element, sieve cell, or parenchyma cell in which are clustered pores through which cytoplasmic connections pass to adjoining cells and which in sieve-tube elemtns are typically most highly developed on the end wall between adjacent elements where they constitute sieve plats
sieve area
an end wall in a sieve-tube element, which facilitates the flow phloem sap in angiosperm sieve tubes
sieve plate
a type of plant cell that is connected to a sieve-tube element by many plasmodesmata and whose nucleus and ribosomes may serve one or more adjacent sieve-tube elements
companion cell
one of the parenchyma cells adjacent to the sieve cells in gymnosperm wood, distinguished by staining deeply with cytoplasmic stains, and apparently associated physiologically with the sieve cells and joined to them by sieve areas
albuminous cell
the outer protective covering of plants
dermal tissue system
the dermal tissue system of nonwoody plants, usually consisting of a single layer of tightly packed cells
epidermis
plant cell on the surface of a leaf or other young plant tissue, where bark is absent
epidermal cell
the two cells that flank the stomatal pore and regulate the opening and closing of the pore
guard cells
a microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange between the environment and the interior of the plant
stoma (-ata)
a minute opening in tissue, as in the skin of an animal, serving as an outlet for perspiration, or in a plant leaf or stem, serving as a means of absorption and transpiration
pore
a hairlike or bristlelike outgrowth, as from the epidermis of a plant
trichome
the protective coat that replaces the epidermis in woody plants during secondary growth, formed of the cork and cork cambium
periderm
an organ in vascular plants that anchors the plant and enables it to absorb water and minerals from the soil
root
a main vertical root that develops from an embryonic root and gives rise to lateral (branch) roots
tap root system
a root system made up of many threadlike members of more or less equal length, as in most grasses
fibrous root system
a cone of cells at the tip of a plant root that protects the apical meristem
root cap
the slimy, viscous substance secrete by the roots of plants, consisting of a hydrated polysaccharide; lubricates the tips of roots as they push their way through the soil during gorwth
mucigel
includes the root apical meristem and its derivatives; in this region, new root cells are produced, including cells of the root cap
region of cell division
where most of the growth occurs as root cells elongate; cell elongation in this zone pushes the tip farther into the soil; the root apical meristem keeps adding cells to the younger end of the zone
region of cell elongation
also called the zone of differentiation; where cells complete their differentiation and become distinct cell types
region of maturation
in plants, ground tissue that is between the vascular tissue and dermal tissue in a root or eudicot system
cortex
in plant roots, the innermost layer of the cortex that surrounds the vascular cylinder
endodermis
also called the Casparian band; band-like structure composed of lignin and suberin found in the anticlinal (radial and transverse) walls of the exodermis and endodermis
Casparian strip
a core of vascular tissue located at the center of the root; contains the xylem and phloem as well as a specialized cell layer called the pericycle
vascular cylinder
the outermost layer in the vascular cylinder, from which lateral roots arise
pericycle
...
endogenous root formation
a vascular plant organ consisting of an alternating system of nodes and internodes that support the leaves and reproductive structures
stem
a dome-shapes mass of dividing cells at the shoot tip
shoot apical meristem
a finger-like projection along the flank of a shoot apical meristem, from which a leaf arises
leaf primordia
a structure that has the potential to form a lateral shoot, or branch; the bud appears in the angle formed between a leaf and a stem
axillary bud
ground tissue that is internal to the vascular tissue in a stem; in many monocot roots, parenchyma cells that form the central core of the vascular cylinder
pith
clusters of xylem and phloem conducting elements that conduct food, water, and minerals throughout the plant
vascular bundles
the main photosynthetic organ of vascular plants
leaf
the stalk of a leaf, which joins the leaf to a node of the stem
petiole
the flattened portion of a typical leaf
blade
one of the usually small, paired parts resembling leaves at the base of a leafstalk in certain plants, such as roses and beans
stipule
leaves having only one blade per petiole
simple
leaves having more than one blade or leaflet per petiole
compound
having the leaflets growing opposite each other in pairs on either side of the stem
pinnate
having three or more veins, leaflets, or lobes radiating from one point
palmate
type of leaf arrangement where the simple leaves are attached in the cotyledonary node and first node
opposite
having a whorl or whorls, radial arrangements of three or more petals, stamens, leaves, etc., around a stem
whorled
type of leaf arrangement where only one leaf is attached in all remaining nodes
alternate
...
helical
any plant adapted to grow wholly or partly submerged in water or wet habitats; an aquatic plant; a wetland plant
hydrophyte
any plant that grows in an environment having a moderate supply of water
mesophyte
any plant adapted to living in a dry arid habitat; a desert plant
xerophyte
leaf cells specialized for photosynthesis; sandwiched between the upper and lower epidermal layers
mesophyll
palisade parenchyma; consists of one or more layers of elongated parenchyma cells on the upper part of the leaf
palisade mesophyll
spongy parenchyma; located below the palisade mesophyll; parenchyma cells that are more loosely arranged, with a labyrinth of air spaces through which carbon dioxide and oxygen circulate around the cells and up to the palisade region
spongy mesophyll
in plants, a vascular bundle in a leaf
vein
arrangement of veins in which the main veins are parallel with each other; common in leaves of monocotyledonous species
parrallel venation
arrangement of veins in leaves resembling a net; most common in dicotyledonous species; also called reticulate venation
netted venation
the separation of leaves, branches, flowers, and bark from plants by the formation of an abscission layer
abscission
growth produced by apical meristems, lengthening stems and roots
primary growth
growth produced by lateral meristems, thickening the roots and shoots of woody plants
secondary growth
embryonic plant tissue in the tips of roots and buds of shoots; the dividing cells of an apical meristem enable the plant to grow in length
apical meristem
cells that remain as sources of new cells
initials
new cells displaced from the meristem
derivatives
the primary meristem in vascular plants that gives rise to the nonvascular tissues, such as cortex, pericycle, and pith; within the seeds of angiosperms, it surrounds the procambium
ground meristem
undifferentiated plant tissue, just behind the growing tip in stems and roots, that develops into conducting tissues
procambium
a cylinder of meristematic tissue in woody plants that adds layers of secondary vascular tissue called secondary xylem (wood) and secondary phloem
vascular cambium
a cylinder of meristematic tissue in woody plants that replaces the epidermis with thicker, tougher cork cells
cork cambium
vascular cambium that is initiated in parenchyma between adjacent vascular bundles in stems
interfascicular cambium
cambium that develops within the vascular bundles in the stem of a plant
fascicular cambium
division of a cell in which the new wall formed is parallel to the surface of the organ
periclinal division
division of a cell in which the new wall formed is at the right angle to the length of an existing cell
anticlinal division
a growth layer of wood formed in secondary xylem during a single period of growth
growth ring
the central core of dark hard wood in tree trunks, consisting of nonfunctioning xylem tissue that has become blocked with resins, tannins, and oils
heartwood
the soft wood, just beneath the bark in tree trunks, that consists of living tissue
sapwood
protective tissue (cork) formed by the phellogen; mature cells are dead with suberin and wax in their walls
phellem
tissue resembling cortex formed by the phellogen
phelloderm
all tissue external to the vascular cambium, consisting mainly of the secondary phloem and layers of periderm
bark
plant tissue that remains embryonic as long as the plant lives, allowing for indeterminate growth
meristem
the primary meristem in vascular plants that gives rise to epidermis
protoderm
those vascular cambial cells that produce the axial system; responsible for forming all the conducting and strengthening cells in the xylem and phloem areas of the stem and root
fusiform initials
those vascular cambial cells that produce the radial system
ray initials
the vascular transport system in a stem that runs vertically; carries water and raw minerals up the stem in the xylem and it carries glucose in the phloem up and down the stem; composed of fibers for strength, sieve-tube members and companion cells in the phloem and fibers, vessels and tracheids in the xylem
axial system
the vascular transport system in a stem that runs horizontally from the center of the setm; carries mostly food out to the margin of the stem; in both the xylem and phloem, the raidal system is made up of parenchyma cells
radial system