Ch23: Cells And Tissues Of The Plant Body

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-morph, morph

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[Gk. morph, form] Suffix or prefix meaning "form." morphogenesis The development of form

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albuminous cells

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Certain ray and axial parenchyma cells in gymnosperm phloem that are spatially and functionally associated with the sieve cells. Also called Strasburger cells

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callose

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A complex polysaccharide, ß 1,3-glucan, synthesized in the plasma membrane and deposited between the plasma membrane and the cell wall; a common wall constituent in the sieve areas of sieve elements; also develops rapidly in reaction to injury in sieve elements and parenchyma cells

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collenchyma cell

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Elongated living cell with unevenly thickened, nonlignified primary cell wall

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companion cell

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A specialized parenchyma cell associated with a sieve-tube element in angiosperm phloem and arising from the same mother cell as the sieve-tube element

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complex tissue

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A tissue consisting of two or more cell types; epidermis, periderm, xylem, and phloem are complex tissues

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cork

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A secondary tissue produced by a cork cambium; made up of polygonal cells, nonliving at maturity, with suberized cell walls that are resistant to the passage of gases and water vapor; the outer part of the periderm. Also called phellem

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cork cambium

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The lateral meristem that forms the periderm, producing cork (phellem) toward the surface (outside) of the plant and phelloderm toward the inside; common in stems and roots of gymnosperms and woody angiosperms. Also called phellogen

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dermal tissue system

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The outer covering tissue of the plant; the epidermis or the periderm

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differentiation

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A developmental process by which a relatively unspecialized cell undergoes a progressive change to a more specialized cell; the specialization of cells and tissues for particular functions during development

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epidermis

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The outermost layer of cells of the leaf and young stems and roots; primary in origin

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fiber

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An elongated, tapering, generally thick-walled sclerenchyma cell of vascular plants; its walls may or may not be lignified; it may or may not have a living protoplast at maturity

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ground tissue

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Tissue other than the vascular tissues, the epidermis, and the periderm. Also called fundamental tissue

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guard cells

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Pairs of specialized epidermal cells surrounding a pore, or stoma; changes in the turgor of a pair of guard cells cause opening and closing of the pore

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meristem

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[Gk. merizein, to divide] Embryonic tissue regions, primarily concerned with formation of new cells

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P-protein

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Phloem protein; a proteinaceous substance found in cells of angiosperm phloem, especially in sieve-tube elements. Once called slime

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parenchyma cell

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Living, generally thin-walled plant cell of variable size and form; the most abundant kind of cell in plants

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perforation plate

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Part of the wall of a vessel element that is perforated

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periderm

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[Gk. peri, around, + derma, skin] Outer protective tissue that replaces epidermis when it is destroyed during secondary growth; includes cork, cork cambium, and phelloderm

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phelloderm

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[Gk. phellos, cork, + derma, skin] A tissue formed inwardly by the cork cambium, opposite the cork; inner part of the periderm

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phloem

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[Gk. phloos, bark] The food-conducting tissue of vascular plants; composed of sieve elements, various kinds of parenchyma cells, fibers, and sclereids

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primary growth

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In plants, growth originating in the apical meristems of shoots and roots, in contrast to secondary growth

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primary plant body

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The part of the plant body arising from the apical meristems and their derivative meristematic tissues; composed entirely of primary tissues

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programmed cell death

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The genetically controlled, or programmed, series of changes in a living cell or organism that lead to its death

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root

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The usually descending axis of a plant, normally below ground, which serves to anchor the plant and to absorb and conduct water and minerals into it

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sclereid

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[Gk. skleros, hard]A sclerenchyma cell with a thick, lignified secondary wall having many pits. Sclereids are variable in form but typically not very long; they may or may not be living at maturity

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sclerenchyma cells

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Cells of variable form and size with more or less thick, often lignified, secondary walls; may or may not be living at maturity; include fibers and sclereids

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sieve area

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A portion of the sieve-element wall containing clusters of pores through which the protoplasts of adjacent sieve elements are interconnected

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sieve cell

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A long, slender sieve element with relatively unspecialized sieve areas and with tapering end walls that lack sieve plates; found in the phloem of gymnosperms

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sieve element

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The cell of the phloem that is involved in the long-distance transport of food substances; sieve elements are further classified into sieve cells and sieve-tube elements

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sieve plate

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The part of the wall of sieve-tube elements that bears one or more highly differentiated sieve areas

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sieve tube

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A series of sieve-tube elements arranged end to end and interconnected by sieve plates

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sieve-tube element

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One of the component cells of a sieve tube; found only in flowering plants and typically associated with a companion cell. Also called sieve-tube member

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simple tissue

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A tissue composed of a single cell type; parenchyma, collenchyma, and sclerenchyma are simple tissues

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stoma

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pl. stomata [Gk. stoma, mouth] A minute opening, bordered by guard cells, in the epidermis of leaves and stems through which gases pass; also used to refer to the entire stomatal apparatus the guard cells plus their included pore

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subsidiary cell

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An epidermal cell morphologically distinct from other epidermal cells and associated with a pair of guard cells. Also called an accessory cell

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tissue

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A group of cells organized into a structural and functional unit

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tissue system

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In plants, a tissue or group of tissues organized into a structural and functional unit in the plant or plant organ. There are three tissue systems dermal, vascular, and ground, or fundamental

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totipotent

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For a plant cell, having the potential to develop into an entire plant

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tracheary element

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The general term for a water-conducting cell in vascular plants; tracheids and vessel elements

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tracheid

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An elongated, thick-walled conducting and supporting cell of xylem, with tapering ends and pitted walls without perforations, in contrast to a vessel element; found in nearly all vascular plants

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transfer cell

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A specialized parenchyma cell with wall ingrowths that increase the surface area of the plasma membrane; apparently functions in the short-distance transfer of solutes

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trichome

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[Gk. trichos, hair] An outgrowth of the epidermis, such as a hair, scale, or water vesicle

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vessel

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[L. vasculum, small vessel] A tubelike structure of the xylem composed of elongated cells (vessel elements) placed end to end and connected by perforations. Its function is to conduct water and minerals through the plant body; found in nearly all angiosperms and a few other vascular plants (for example, gnetophytes)

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vessel element

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One of the cells composing a vessel. Also called vessel member

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xylem

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[Gk. xylon, wood] A complex vascular tissue through which most of the water and minerals of a plant are conducted; characterized by the presence of tracheary elements