!version: $Revision: 1.7 $ !date: Tue Mar 11 12:03:14 PST 2003 !saved-by: lreiser !autogenerated-by: DAG-Edit version 1.316 ! !Gene Ontology definitions ! term: abscission zone goid: TAIR:0000146 definition: Zone at base of leaf, flower, fruit, or other plant part that contains an abscission (or separation) layer and a protective layer, both involved in the abscission of the plant part. definition_reference: ISBN:047124529 term: adult leaf goid: TAIR:0000118 definition: a leaf with waxes, cell types or other features characteristic of leaves in an adult (reproductive )phase definition_reference: TAIR:lr term: aerenchyma cell goid: TAIR:0000294 definition: Parenchyma tissue containing particularly large intercellular spaces of schizogenous, lysigenous, or rhexigenous origin. definition_reference: ISBN:047124529 term: aleurone layer goid: TAIR:0000308 definition: Outermost layer of endosperm in cereals and many other taxa that contains protein bodies and enzymes concerned with endosperm digestion. definition_reference: ISBN:047124529 term: anther goid: TAIR:0000155 definition: The pollen-bearing part of the stamen. definition_reference: ISBN:047125208 term: antipodal cell goid: TAIR:0000192 definition: cells located at the chalazal end of the mature embryo sac in angiosperms definition_reference: ISBN:047125208 term: aperture goid: TAIR:0000299 definition: A depressed region in the pollen wall in which thick intine is covered by thin exine; the pollen grain emerges through the aperture. definition_reference: ISBN:0471245208 term: apical cell goid: TAIR:0000178 definition: the uppermost cell formed after the first division of the zygote. definition_reference: TAIR:lr term: Arabidopsis anatomy goid: TAIR:0000111 definition: The structure of an organism, specifically Arabidopsis thaliana definition_reference: :http //www.academicpress.com/inscight/11261996/anatomy1.htm term: atrichoblast goid: TAIR:0000263 definition: cell formed after asymmetric division of root epidermal cell that does not give rise to a root hair definition_reference: ISBN:0387987819 term: axillary meristem goid: TAIR:0000232 definition: Meristems formed along the lateral axis of the shoot. definition_reference: TAIR:lr term: axillary shoot goid: TAIR:0000338 definition: shoot formed formed axillary to the primary shoot meristem. definition_reference: TAIR:lr term: basal cell goid: TAIR:0000179 definition: the lowermost cell formed after the first division of the zygote. definition_reference: TAIR:lr term: bundle sheath goid: TAIR:0000023 definition: Layer or layer of cells enclosing the vascular bundle in a leaf; may consist of parenchyma or sclerenchyma. definition_reference: ISBN:0471245208 term: cambial initial goid: TAIR:0000295 definition: Cells so localized in the vascular cambium or phellogen that their periclinal divisions can contribute cells either to the outside or to the inside of the axis; in vascular cambium, classified into fusiform initials (source of axial cells of xylem and phloem) and ray initials (source of the ray cells). definition_reference: ISBN:047124529 term: carpel goid: TAIR:0000126 definition: Leaflike organ in angiosperms producing one or more ovules; a constituent of the gynoecium. definition_reference: ISBN:047124529 term: casparian strip goid: TAIR:0000257 definition: A band like wall formation within primary walls that contains suberin and lignin; typical of endodermal cells in roots, in which it occurs in radial and transverse anticlinal walls. definition_reference: ISBN:047124529 term: central cell goid: TAIR:0000194 definition: cell type containing the two polar nuclei which, after double fertilization, will develop into the endosperm. definition_reference: TAIR:lr term: central root cap goid: TAIR:0000254 definition: The central part of a rootcap in which the cells are arranged in longitudinal files. definition_reference: ISBN:047124529 term: central zone goid: TAIR:0000224 definition: An area of densely cytoplasmic cells that divide infrequently. Functions as a population of stem cells that replenishes the meristem. definition_reference: TAIR:lr definition_reference: ISBN:0521288959 term: chalaza goid: TAIR:0000237 definition: Region in the ovule opposite the micropyle where the integuments and the nucellus merge with the funiculus. definition_reference: ISBN:047125208 term: chalazal endosperm goid: TAIR:0000201 definition: the portion of the endosperm located nearest the chalazal region of the ovule. definition_reference: TAIR:lr definition_reference: ISBN:047124529 term: chlorenchyma goid: TAIR:0000241 definition: Parenchyma containing chloroplasts; a component of leaf mesophyll and other green parenchyma. definition_reference: ISBN:047124529 term: collenchyma goid: TAIR:0000209 definition: Elongated living cells with unevenly thickened nonlignified primary walls. Common in regions of primary growth in stems and leaves. definition_reference: ISBN:047124529 term: cotyledon goid: TAIR:0000138 definition: Leaf or leaf-like organ formed during embryogenesis. Specialization includes accumulation of storage reserves that are mobilized during seed germination. definition_reference: TAIR:lr term: cotyledon abaxial epidermis goid: TAIR:0000211 definition: epidermal layer of the cotyledon facing away from the axis. definition_reference: TAIR:lr term: cotyledon adaxial epidermis goid: TAIR:0000210 definition: epidermal layer located on the side of the cotyledon facing the axis, definition_reference: TAIR:lr term: cotyledon primordium goid: TAIR:0000365 definition: the earliest differentiated state of a cotyledon. definition_reference: TAIR:lr definition_reference: ISBN:047125208 term: cotyledon vascular system goid: TAIR:0000119 definition: vascular system formed in cotyledons definition_reference: TAIR:lr term: degenerate megaspore goid: TAIR:0000245 definition: in monosporic and bisporic megasporogenesis: the megaspore(s) that do not participate in megagametogenesis. definition_reference: TAIR:lr term: egg apparatus goid: TAIR:0000189 definition: The egg cell and two synergids located at the micropylar end of the female gametophyte, or the embryo sac, in angiosperms. definition_reference: ISBN:047125208 term: egg cell goid: TAIR:0000190 definition: the female gamete definition_reference: TAIR:lr term: elongation zone goid: TAIR:0000324 definition: the portion of the root that includes small, densely cytoplasmic cells that are dividing and expanding in size. definition_reference: ISBN:0879694289 term: embryo goid: TAIR:0000172 definition: a product of fertilization that represents the next (sporophytic) generation definition_reference: TAIR:lr term: embryonic axis goid: TAIR:0000387 definition: the stem component of the embryo. definition_reference: TAIR:lr term: embryonic ground tissue goid: TAIR:0000367 definition: ground tissue (parenchymatous) layers found in the embryo. definition_reference: TAIR:lr term: endodermis goid: TAIR:0000003 definition: It is the innermost layer of the cortex in roots and stems of seed plants. definition_reference: ISBN:047124520 term: endosperm goid: TAIR:0000197 definition: The nutritive tissue formed within the embryo sac of angiosperms from the central cell containing the primary endosperm nucleus. definition_reference: ISBN:047125208 term: endothecium goid: TAIR:0000158 definition: A wall layer in the anther, usually with secondary wall thickenings. definition_reference: TAIR:047125208 term: epidermal initial goid: TAIR:0000349 definition: a relatively unspecialized cell that will give rise to specialized cell types of the epidermis definition_reference: TAIR:lr term: epidermis goid: TAIR:0000202 definition: the outer layer of cells in the plant body, primary in origin. definition_reference: ISBN:0471245208 term: fasicular cambium goid: TAIR:0000360 definition: Vascular cambium originating from procambium within a vascular bundle, or fascicle. definition_reference: ISBN:047124529 term: fiber tracheid goid: TAIR:0000355 definition: A fiberlike tracheid in the secondary xylem; commonly thick walled, with pointed ends and bordered pits that have lenticular to slitlike apertures. definition_reference: ISBN:047124529 term: filliform apparatus goid: TAIR:0000193 definition: A complex of cell wall invaginations in a synergid cell similar to those in transfer cells. definition_reference: ISBN:0471245208 term: floral organ goid: TAIR:0000122 definition: an organ that is part of the flower: the sexual reproductive structure of Angiosperms. definition_reference: TAIR:lr term: functional megaspore goid: TAIR:0000244 definition: in monosporic and bisporic megasporogenesis: the megaspore(s) that will undergo megagametogenesis. definition_reference: TAIR:lr term: funiculus goid: TAIR:0000239 definition: The stalk of the ovule. definition_reference: ISBN:047124529 term: gametophyte goid: TAIR:0000427 definition: the haploid organism (or phase) which bears (forms)the gametes, definition_reference: TAIR:lr term: generative cell goid: TAIR:0000168 definition: The cell that will give rise to the generative nuclei which will participate in fertilization definition_reference: TAIR:lr term: guard cell goid: TAIR:0000293 definition: one of a pair of cells flanking the stomatal pore and causing the opening and closing of the pore by changes in turgor. definition_reference: ISBN:047124529 term: guard mother cell goid: TAIR:0000351 definition: epidermal cell that that divides to produce the guard cells. definition_reference: ISBN:047124529 term: gynoecium goid: TAIR:0000326 definition: Collective term for the carpels in an angiosperm flower; part of the flower in which female gametogenesis occurs. definition_reference: ISBN:047124529 term: hydathode goid: TAIR:0000323 definition: A structural modification of vascular and ground tissues, usually in a leaf, that permits the release of water through a pore in the epidermis; may be secretory in function. definition_reference: TAIR:lr term: hypocotyl goid: TAIR:0000310 definition: the axial part of the embryo or seedling located between the cotyledon or cotyledons and the radicle. definition_reference: ISBN:0471245208 term: hypophysis goid: TAIR:0000181 definition: The uppermost cell of suspensor from which part of the root and rootcap in the embryo of angiosperms are derived. definition_reference: ISBN:047125208 term: idioblast goid: TAIR:0000283 definition: A cell in a tissue that markedly differs in form, size, or contents from other cells in the same tissue. definition_reference: ISBN:047124529 term: juvenile leaf goid: TAIR:0000216 definition: a leaf with cellular or morphologcial or anatomical characteristics of a juvenile (non-reproductive) plant. definition_reference: TAIR:lr term: lamina goid: TAIR:0000221 definition: Blade, or expanded part of the leaf. definition_reference: ISBN:047124529 term: lateral root meristem goid: TAIR:0000031 definition: The meristem found in lateral roots. definition_reference: TAIR:lr term: lateral root primordium goid: TAIR:0000032 definition: An organized group of cells derived from the root pericycle that will differentiate into a new root, definition_reference: TAIR:lr term: lenticel goid: TAIR:0000292 definition: An isolated region in the penderm distinguished from the phellem in having intercellular spaces; the tissue may or may not be suberized. definition_reference: ISBN:047124529 term: lower tier goid: TAIR:0000321 definition: cells formed by division of the embryonic apical cell that are distal to the apex. definition_reference: ISBN:0879694289 definition_reference: TAIR:lr term: megagametophyte goid: TAIR:0000188 definition: Haploid generation that produces the gametes in higher plants, Female gametophyte in heterosporous plants; embryo sac within the ovule in angiosperms. definition_reference: ISBN:047125208 definition_reference: TAIR:lr term: megaspore goid: TAIR:0000243 definition: A haploid (1n) spore developing into a female gametophyte in heterosporous plants. definition_reference: ISBN:0471245208 term: megasporocyte goid: TAIR:0000431 definition: A diploid (2n) cell that undergoes meiosis and produces four haploid (1n) megaspores; also called megaspore mother cell. definition_reference: ISBN:0471245208 term: metaphloem goid: TAIR:0000279 definition: Part of the primary phloem that differentiates after the protophloem and before the secondary phloem, if any of the latter is formed in a given taxon. definition_reference: TAIR:047125208 term: metaxylem goid: TAIR:0000372 definition: Part of the primary xylem that differentiates after the protoxylem and before the secondary xylem, if any of the latter is formed in a given taxon. definition_reference: ISBN:047125208 term: micropylar endosperm goid: TAIR:0000200 definition: the region of the endosperm closest to the micropylar region of the ovule. definition_reference: TAIR:lr term: micropyle goid: TAIR:0000238 definition: The opening in the integuments of an ovule through which the pollen tube usually enters the embryo sac. definition_reference: ISBN:047125208 term: microspore goid: TAIR:0000297 definition: A haploid (1n) spore developing into a male gametaphyte in heterosporous plants; the uninucleate pollen grain in seed plants. definition_reference: ISBN:0471245208 term: microsporocyte goid: TAIR:0000160 definition: A diploid (2n) cell that undergoes meiosis and forms four haploid (1n) microspores; also called microspore mother cell and, in seed plants, pollen mother cell. definition_reference: ISBN:0471245208 term: midvein goid: TAIR:0000235 definition: the central or usually most prominent vein in a leaf or leaf-like organ. definition_reference: TAIR:lr term: mucilage cell goid: TAIR:0000373 definition: Cell containing mucilages or gums or similar carbohydrate material characterized by the property of swelling in water. definition_reference: ISBN:047124529 term: myrosin cell goid: TAIR:0000352 definition: Cell containing glucosinolates ("mustard oil glucosides") and myrosinases, enzymes hydrolysing the glucosinolates. Occur in eleven dicotyledon families, the two largest of which are the Brassicaceae and Euphorbiaceae. definition_reference: ISBN:047124529 term: nectary goid: TAIR:0000123 definition: A multicellular glandular structure secreting a liquid containing organic substances including sugar. Occurs in flowers (floral nectary) and on vegetative plant parts (extrafloral nectary). definition_reference: ISBN:047124529 term: nectary epidermis goid: TAIR:0000207 definition: the epidermal layer of the nectary. definition_reference: TAIR:lr term: nectary parenchyma goid: TAIR:0000309 definition: the ground tissue of the nectary. definition_reference: TAIR:lr term: node goid: TAIR:0000344 definition: the part of the stem at which one or more leaves are attached;not sharply delimited anatomically. definition_reference: ISBN:0471245208 term: nucellus goid: TAIR:0000240 definition: Inner part of an ovule in which the embryo sac develops. Commonly considered to be equivalent to the megasporangium. definition_reference: ISBN:047125208 term: ovary goid: TAIR:0000128 definition: Lower part of a carpel (simple pistil) or of a gynoecium composed of united carpels (compound pistil) containing the ovules and differentiating into the fruit. definition_reference: ISBN:047124529 term: ovary ground tissue goid: TAIR:0000163 definition: the ground tissue layer of the ovary. definition_reference: TAIR:lr term: ovary inner epidermis goid: TAIR:0000137 definition: inner epidermal layer of the ovary wall. definition_reference: TAIR:lr term: ovary outer epidermis goid: TAIR:0000139 definition: outer epidermal layer of the ovary wall. definition_reference: TAIR:lr term: ovary parenchyma goid: TAIR:0000242 definition: parenchyma layer of the ovary wall. definition_reference: TAIR:lr term: ovary vascular system goid: TAIR:0000129 definition: vascular system of the ovary definition_reference: TAIR:lr term: ovule goid: TAIR:0000236 definition: A structure in seed plants enclosing the female gametophyte and composed of the nucellus, one or two integuments, and funiculus; differentiates into the seed. definition_reference: ISBN:047124529 term: palisade parenchyma goid: TAIR:0000342 definition: Leaf mesophyll parenchyma characterized by elongated form of cells and their arrangement with their long axes perpendicular to the surface of the leaf. definition_reference: ISBN:047124529 term: passage cell goid: TAIR:0000353 definition: Cell in exodermis or endodermis that remains thin walled when the associated cells develop thick secondary walls. Has casparian strip in endodermis. definition_reference: ISBN:047124529 term: pavement cell goid: TAIR:0000332 definition: epidermal cells with a characteristic convoluted anticlinal cell walls that give a jigsaw like appearance to the lamina. definition_reference: ISBN:087694289 term: pedicel goid: TAIR:0000220 definition: The stalk of an individual flower. definition_reference: ISBN:047124529 term: pericarp goid: TAIR:0000347 definition: Fruit wall developed from the ovary wall. definition_reference: ISBN:047124529 term: pericycle goid: TAIR:0000260 definition: Part of ground tissue of the stele located between the phloem and the endodermis. In seed plants, regularly present in roots, absent in most stems. definition_reference: ISBN:047124529 term: peripheral zone goid: TAIR:0000225 definition: organogenic region of the meristem. characterized by higher rates of cell division. definition_reference: TAIR:lr definition_reference: ISBN:0521288959 term: petal goid: TAIR:0000124 definition: A unit of the corolla of a flower. definition_reference: ISBN:047124529 term: petal parenchyma goid: TAIR:0000234 definition: the ground tissue of the petal. definition_reference: TAIR:lr term: petiole goid: TAIR:0000121 definition: the stalk of a leaf. definition_reference: ISBN:0471245208 term: phloem goid: TAIR:0000278 definition: The principal food-conducting tissue of the vascular plant composed mainly of sieve elements, various kinds of parenchyma cells, fibers, and sclereids. definition_reference: ISBN:047125208 term: phloem initial goid: TAIR:0000400 definition: A cambial cell on the phloem side of the cambial zone that is the source of one or more cells arising by periclinal divisions and differentiating into phloem elements with or without additional divisions in various planes. Sometimes called phloem mother cell. definition_reference: ISBN:0471245208 term: phloem parenchyma goid: TAIR:0000359 definition: parenchyma tissue found in the phloem. definition_reference: TAIR:lr term: polar nucleus goid: TAIR:0000196 definition: One of two nuclei in the central cell of a mature embryo sac. The two nuclei are derived from groups of nuclei at the two opposite poles of the eight-nucleate embryo sac. definition_reference: ISBN:047125208 term: pollen sac goid: TAIR:0000156 definition: Sporangium in which microspores are formed; anther locule and its walls in angiosperms. definition_reference: ISBN:047125208 term: primary endosperm nucleus goid: TAIR:0000195 definition: Nucleus resulting from the fusion of the male gamete and two polar nuclei in the central cell of the embryo sac. definition_reference: ISBN:0471245208 term: primary phloem goid: TAIR:0000280 definition: Phloem tissue differentiating from procambium during primary growth and differentiation of a vascular plant. Commonly divided into the earlier protophloem and the later metaphloem. Not differentiated into axial and ray systems. definition_reference: ISBN:047125208 term: primary root meristem goid: TAIR:0000030 definition: The region located at the distal end of the root containing actively dividing cells that produce new tissues of the root. The primary root meristem is formed in the embryo (the basal end of the shoot-root axis), in contrast to lateral root meristems. definition_reference: TAIR:lr term: procambium goid: TAIR:0000345 definition: Primary meristem or meristematic tissue which differentiates into the primary vascular tissue. Also called provascular tissue. definition_reference: ISBN:047125208 term: protoderm goid: TAIR:0000182 definition: Primary meristem or meristematic tissue giving rise to the epidermis; also epidermis in meristematic state. May or may not arise from independent initials in the apical meristem. definition_reference: ISBN:047124529 term: protophloem goid: TAIR:0000346 definition: the first-formed elements of the phloem in a plant organ. First part of the primary phloem. definition_reference: ISBN:0471245208 term: protoxylem goid: TAIR:0000272 definition: The first formed elements of the xylem in a plant organ. First part of the primary xylem. definition_reference: ISBN:047125208 term: quiescent center goid: TAIR:0000259 definition: The initial region in the apical meristem that has reached a state of relative inactivity; common in roots. definition_reference: ISBN:047124529 term: radicle goid: TAIR:0000268 definition: the embryonic root. Forms the basal continuation of the hypocotyl in an embryo. definition_reference: ISBN:047124529 term: raphe goid: TAIR:0000364 definition: A ridge along the body of the seed formed by the part of the funiculus that is adnate to the ovule (in an anatropous ovule). definition_reference: ISBN:047124529 term: replum goid: TAIR:0000135 definition: in an ovary or fruit, a false septum formed bu ingrowth from the placenta rather than from the carpel walls. definition_reference: ISBN:0140514031 term: rib zone goid: TAIR:0000226 definition: region of the meristem that lies below the central zone and within the peripheral zone definition_reference: ISBN:0521288959 definition_reference: TAIR:lr term: root cap goid: TAIR:0000253 definition: A thimblelike mass of cells covering the apical meristem of the root. definition_reference: ISBN:047125208 term: root cell culture goid: TAIR:0000040 definition: Cell culture derived from roots. definition_reference: TAIR:mg:sm term: root cortex goid: TAIR:0000258 definition: the primary tissue located between the vascular system and the epidermis. definition_reference: ISBN:047125208 term: root endodermis goid: TAIR:0000252 definition: The layer of ground tissue forming a sheath around the vascular region and having the casparian strip in its anticlinal walls; may have secondary walls later. It is the innermost layer of the cortex in roots and stems of seed plants. definition_reference: ISBN:047124529 term: root epidermis goid: TAIR:0000361 definition: epidermal layer of the root definition_reference: ISBN:047124529 term: root hair goid: TAIR:0000256 definition: A type of trichome on root epidermis that is a simple extension of an epidermal cell and is concerned with absorption of soil solution. definition_reference: ISBN:0471245208 term: sclerenchyma goid: TAIR:0000300 definition: Cell variable in form and size, being more or less thick, often lignified, secondary walls. Belongs to the category of subcells and may or may not be devoid of protoplast at maturity. definition_reference: ISBN:047124529 term: seed coat epidermis goid: TAIR:0000371 definition: the epidermal layer found on the outer surface of an organ definition_reference: TAIR:lr term: sepal goid: TAIR:0000125 definition: A unit of the calyx. definition_reference: ISBN:047124529 term: sepal epidermis goid: TAIR:0000176 definition: the epidermal layer of the sepal. definition_reference: TAIR:lr term: septum goid: TAIR:0000131 definition: any partition, whether within a cell, as in a septate fibre, or in an organ such as a fruit. definition_reference: ISBN:0140514031 term: sieve cell goid: TAIR:0000285 definition: A type of sieve element that has relatively undifferentiated sieve areas (with narrow pores), rather uniform in structure on all walls; that is, there are no sieve plates. Typical of gymnosperms and lower vascular plants. definition_reference: ISBN:047124529 term: sieve element goid: TAIR:0000286 definition: The cell in the phloem tissue concerned with mainly longitudinal conduction of food materials. Classified into sieve cell and sieve tube member. definition_reference: ISBN:0471245208 term: sieve plate goid: TAIR:0000287 definition: The part of the wall of a sieve element bearing one or more highly differentiated sieve areas. Typical of angiosperms. definition_reference: ISBN:0471245208 term: sieve tube member goid: TAIR:0000289 definition: One of the series of cellular components of a sieve tube. It shows a more or less pronounced differentiation between sieve plates (wide pores) and lateral sieve areas (narrow pores). Also sieve tube element and the obsolete sieve tube segment. definition_reference: ISBN:047124529 term: silique goid: TAIR:0000208 definition: a dry dehiscent fruit common in Brassicas. definition_reference: ISBN:0140514031 term: specialization zone goid: TAIR:0000348 definition: the portion of the root located behind the elongation zone containing cells that are differentiating into their final form and function. definition_reference: ISBN:0879694289 term: spongy parenchyma goid: TAIR:0000143 definition: Leaf mesophyll parenchyma with conspicuous intercellular spaces. definition_reference: ISBN:047124529 term: stamen goid: TAIR:0000152 definition: Floral organ producing the pollen and usually composed of anther and filament. The stamens together constitute the androecium. definition_reference: ISBN:047124529 term: starch sheath goid: TAIR:0000002 definition: applied to the innermost regions (one or more cell layers)of the cortex when this region is characterized by conspicuous and rather stable accumulation of starch. definition_reference: ISBN:047124520 term: starch sheath cell goid: TAIR:0000020 definition: Cells characterized by conspicuous and rather stable accumulation of starch. definition_reference: ISBN:044174520 term: stele goid: TAIR:0000314 definition: a morphologic unit of the plant body comprising the vascular system and associated ground tissue (e.g. pericycle, interfasicular regions and pith). definition_reference: ISBN:0471245208 term: stem epidermis goid: TAIR:0000112 definition: epidermal layer of the stem definition_reference: TAIR:lr term: stigma goid: TAIR:0000132 definition: The region of the carpel, in many taxa at the apex of the style, that serves as a surface upon which the pollen germinates. definition_reference: ISBN:047124529 term: stigma epidermis goid: TAIR:0000164 definition: epidermal layer of the stigma. definition_reference: TAIR:lr term: stigmatic papillae goid: TAIR:0000141 definition: ). A soft protuberance on an epidermal cell of the stigma. definition_reference: ISBN:047124529 term: stipule goid: TAIR:0000215 definition: small appendages formed at the base of a leaf. definition_reference: ISBN:0716719460 term: stomatal complex goid: TAIR:0000281 definition: An opening in the epidermis of leaves and stems bordered by two guard cells and serving in gas exchange. definition_reference: ISBN:047124529 term: stomium goid: TAIR:0000157 definition: A fissure or pore in the anther lobe through which the pollen is released. Its formation is a type of dehiscence. definition_reference: ISBN:0471245208 term: style goid: TAIR:0000133 definition: Extension of the top of the ovary, usually columnar, through which the pollen tube grows. definition_reference: ISBN:047124529 term: style epidermis goid: TAIR:0000165 definition: epidermal layer of the style. definition_reference: TAIR:lr term: style parenchyma goid: TAIR:0000307 definition: parenchyma tissues of the style. definition_reference: TAIR:lr term: subsidiary cell goid: TAIR:0000284 definition: an epidermal cell associated with a stoma and at least morphologically distinguishable from the epidermal cells composing the groundmass of the tissue. definition_reference: ISBN:047124520 term: suspensor goid: TAIR:0000175 definition: An extension at the base of the embryo that anchors the embryo in the embryo sac and pushes it into the endosperm. definition_reference: ISBN:047124529 term: synergid goid: TAIR:0000191 definition: cells in the micropylar end of the embryo sac associated with the egg in the egg apparatus of angiosperms. Play a vital role in fertilization. definition_reference: ISBN:047125208 term: tapetum goid: TAIR:0000159 definition: In anther, a layer of cells lining the locule and absorbed as the pollen grains mature. definition_reference: ISBN:047125208 term: tissues and tissue systems goid: TAIR:0000140 definition: Tussues are a group of cells organized into a structural and functional unit. Component cells may be alike (simple tissue) or varied (complex tissue). Tissue systems are tissue or tissues in a plant or plant organ structurally and functionally organized into a unit. Commonly three tissue systems are recognized, dermal, vascular, and fundamental (ground tissue system). definition_reference: ISBN:0471245208 term: tracheary element goid: TAIR:0000290 definition: general term for a water conducting cell, tracheid or vessel member. definition_reference: ISBN:047124529 term: tracheid goid: TAIR:0000301 definition: A tracheary element of the xlyem that has no perforations, as contrasted with a vessel member. May occur in primary and in secondary xylem. May have any kind of secondary wall thickening found in tracheary elements. definition_reference: ISBN:047124529 term: transmitting tract goid: TAIR:0000134 definition: The tissue in the style of a flower through which the pollen tube grows between the stigma and the ovarian cavity. Also called pollen conducting tissue. definition_reference: ISBN:047124529 term: trichoblast goid: TAIR:0000262 definition: Commonly used for a cell in root epidermis that gives rise to a root hair. The daughter cell produced by the asymmetric division of a root epidermal cell that gives rise to a root hair. definition_reference: ISBN:047124529 term: trichome goid: TAIR:0000282 definition: An outgrowth from the epidermis. Trichomes vary in size and complexity and include hairs, scales, and other structures and may be glandular. definition_reference: ISBN:047124529 term: upper tier goid: TAIR:0000354 definition: In an eight celled embryo, the upper four cells formed by mitotic division of the apical cell. These cells will give rise to the apical meristem and cotyledons. definition_reference: ISBN:089694269 term: vascular bundle goid: TAIR:0000362 definition: A strandlike part of the vascular system composed of xylem and phloem. definition_reference: ISBN:047124529 term: vascular cambium goid: TAIR:0000356 definition: Lateral meristem that forms the secondary vascular tissues, secondary phloem and secondary xylem, in stem and root. I located between those two tissues and, by periclinal divisions, gives off cells toward both tissues. definition_reference: ISBN:047125208 term: vascular system goid: TAIR:0000270 definition: The total of the vascular tissues in their specific arrangement in a plant or plant organ. definition_reference: ISBN:047125208 term: vascular tissue goid: TAIR:0000327 definition: A general term referring to either or both vascular tissues, xylem and phloem. definition_reference: ISBN:047125208 term: vegetative cell goid: TAIR:0000169 definition: Cell type formed after the first mitotic division of the microgametophye, The nucleus of this cell migrates to the tip of the pollen tube after germination and desintigrates when the pollen tube penetrates the nucellus. definition_reference: TAIR:lr definition_reference: ISBN:0140514031 term: vegetative meristem goid: TAIR:0000033 definition: A shoot meristem that gives rise to only non-reproductive organs and tissues. definition_reference: TAIR:lr term: xylem goid: TAIR:0000271 definition: The principal water-conducting tissue in vascular plants characterized by the presence of tracheary elements. The xylem may also serve as a supporting tissue, especially the secondary xylem (wood). definition_reference: ISBN:047125208 term: xylem element goid: TAIR:0000273 definition: Cells composing the xylem definition_reference: ISBN:047124529 term: xylem fiber cell goid: TAIR:0000274 definition: A fiber of the xylem tissue, Two types are recognized, int he secondary xylem,fiber tracheids and libriform fibers. definition_reference: ISBN:047124529 term: xylem initial goid: TAIR:0000275 definition: A cambial cell on the xylem side of the cambial zone that is the source of one or more cells arising by periclinal divisions and differentiating into xylem elements either with or without additional divisions in various planes. Sometimes called xylem mother cell. definition_reference: ISBN:047125208 term: xylem intitial goid: TAIR:0000357 definition: A cambial cell on the xylem side of the cambial zone that is the source of one or more cells arising by periclinal divisions and differentiating into xylem elements either with or without additional divisions in various planes. definition_reference: ISBN:047124529 term: xylem parenchyma goid: TAIR:0000358 definition: parenchyma tissue of the xylem definition_reference: TAIR:lr