!version: $Revision: 1.24 $
!date:                 Mon Apr 19 16:48:38 EDT 2004
!saved-by: Pankaj
!autogenerated-by: DAG-Edit version 1.410
!
!Gene Ontology definitions
!
term: abaxial protoderm
id: pj:0006082
definition: The outermost layer of the shoot apical meristem which gives rise to the leaf epidermis that is present further away from or directed away from the main shoot axis.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: abscission zone
id: GRO: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: accessory transfusion tissue
id: pj:0006086
definition: Teh accessory tissue  extending laterally into the mesophyll rather than remaining associated with the vascular bundles.
definition_reference: ISBN:0080374913

term: adaxial protoderm
id: pj:0006083
definition: The outermost layer of the shoot apical meristem which gives rise to the leaf epidermis that is present further towards the main shoot axis.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: adventitious root apical meristem
id: pj:0006021
definition: Apical or primary, meristem of the adventitious root.
definition_reference: GR:pj

term: adventitious root epidermis
id: pj:0006039
definition: The outer most cell layer of the the adventitious root.
definition_reference: GR:pj

term: aerenchyma
id: GRO:0005702
definition: Parenchyma tissue containing particularly large intercellular spaces of schizogenous, lysigenous, or rhexigenous origin.
definition_reference: ISBN:0080374913
definition_reference: GR:pj
comment: As applied to an intercellular space, originating by a combination of two processes, separation and degradation of cell walls.

term: aleurone layer
id: GRO:0005360
definition: The outermost layer of endosperm tissue of the seeds. The cells are characterized by presence of protein bodies containing seed storage proteins.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: angular collenchyma
id: GRO:0005621
definition: A form of collenchyma in which the primary wall thickening is most prominent in the angles where three or more cells are joined.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: anther epidermis
id: pj:0006059
definition: The epidermal cell layer of the anther.
definition_reference: GR:pj

term: bundle sheath
id: pj:0006023
definition: A layer or layers of cells surrounding the vascular bundles of leaves. It may consist of parenchyma or sclerenchya.
definition_reference: ISBN:0080374913

term: bundle sheath extension
id: pj:0006022
definition: A strip of ground tissue present along the leaf veins and extending from the bundle sheath to the epidermis. It may be present on both sides of the vein or on one side only and may consist of parenchyma or sclerenchyma.
definition_reference: ISBN:0080374913

term: callus
id: GRO:0005052
definition: A tissue formed as a result of wounding or a tissue developing in a tissue culture.
definition_reference: GR:pj

term: cambium
id: GRO:0005597
definition: A lateral meristem the cells of which divide mostly periclinally. 
definition_reference: ISBN:0080374913

term: cambium-like transitional zone
id: pj:0006067
definition: This is a cup-shaped region in shoot apical meristem found between the central mother cell and the rib and peripheral zone. The cells of this zone are derived from the corpus intials, but in some cases they arise also from tunica initials.
definition_reference: ISBN:0080374913
comment: If found, this zone is only a temporary feature in many of the plants. It disappears towards the end of the plastochron.

term: casparian strip
id: GRO:0000257
definition: A band like wall formation within primary walls that contains suberin and lignin; typical of endodermal cells, in which it occurs in radial and transverse anticlinal walls.
definition_reference: ISBN:047124529

term: cellular endosperm
id: GRO:0000199
definition: In this type of endosprem the first karyokinesis event is accompanied with the cytokinesis. The planes of teh subsequent divisions may be parallel to that of the first division. 
definition_reference: ISBN:0080374913
definition_reference: ISBN:0471245194

term: central zone
id: GRO: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: chalazal region
id: GRO:0000201
definition: The part of the endosperm located nearest the chalazal of the ovule.
definition_reference: TAIR:lr
definition_reference: ISBN:047124529

term: chlorenchyma
id: GRO:0005426
definition: A chloroplast-containing parenchyma tissue.
definition_reference: ISBN:0080374913

term: collenchyma
id: GRO:0005423
definition: The collenchyma is the typical supporting tissue of the primary plant body and growing plant parts. Its prosenchymatous cells are living at maturity and are always kept in a primary state, that they are never lignified. 
definition_reference: GR:pj
comment: Collenchyma walls are interspersed with groups of pits that tend to be organized in special areas. The name collenchyma derives from the Greek word "kolla", meaning "glue", which refers to the thick, glistening appearance of the walls in fresh tissues due to pectin deposition.

term: cork cambium
id: GRO:0005599
definition: An instance of a secondary lateral meristem which produces the phellem and the phelloderm.
definition_reference: ISBN:0080374913

term: corpus
id: PO:0009024
definition: Group of cells located beneath anticlinally dividing peripheral layers (tunica) and dividing in many planes. In apical shoot meristem. Such division cause the increase in the volume of shoot.
definition_reference: ISBN:0080374913

term: cortex
id: GRO:0005708
definition: The primary ground tissue region between the vascular system and the epidermis in stem and root. 
definition_reference: GR:pj
comment: Term also used with reference to peripheral region of a cell protoplast.

term: crown root epidermis
id: pj:0006038
definition: The outer most cell layer of the the crown roots.
definition_reference: GR:pj

term: endodermis
id: GRO: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: endodermoid
id: pj:0006064
definition: The layer of cels present in the similar position as that of  endodermis and probably driffering physiologically from adjacent layers but without distinctive wall charateristics.
definition_reference: ISBN:essau

term: endosperm
id: GRO:0005361
definition: It is a storage tissue that provides nutrition for the embryo and young seedlings. It develops from the mitotic division of the endosperm nucleus, which results from teh fusion of one of teh sperm nuclei with teh two polar nuclei or with the secondary nucleus. Thsi division usually precedes that of teh zygote.
definition_reference: GR:pj
definition_reference: web:http //www.ibiblio.org/botnet/glossary/a_xii.html

term: endosperm parenchyma
id: GRO:0005415
definition: Relatively unspecialized ground tissue present in the seed endosperm.  Often the tissue is devoid of intercallular spaces.
definition_reference: ISBN:0080374913

term: epidermis
id: GRO:0005679
definition: An outermost cell layer of primary tissues of the plant. Sometimes it is comprised of more than one layer. 
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: exodermis
id: GRO:0005772
definition: The sub epidermal layers of cells of the root cortex. It is similar in structure and cytochemical characteristics of  the endodermis. It is also the outermost layer or layers of cells in the root cortex.
definition_reference: GR:pj
definition_reference: ISBN:0080374913
comment: The cell walls are thickened and contain suberin. Absent in pteridophytes, fibrous in Phoenix and accompanied by sclerenchyma in Ananas.

term: foliage leaf epidermis
id: pj:0006016
definition: Epidermal layer of a leaf
definition_reference: GR:pj

term: foliage leaf mesophyll
id: GRO:0005645
definition: The chloroplast-containing, photosynthetic parenchymatous tissue situated between the two epidermal layers of the foliage leaf.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: free nuclear endosperm
id: GRO:0000198
definition: A multinucleate endosperm. In thsi type the first karyokinesis is not followed by cytokinesis.
definition_reference: ISBN:0080374913
definition_reference: ISBN:0471245194

term: ground tissue
id: PO:0009016
definition: Tissues other than the vascular tissues, epidermis and the periderm.
definition_reference: GR:pj

term: helobial endosperm
id: pj:0006017
definition: It is an intermediate between the nuclear and the celluar type of endosperms. . In this type of endosperm tissue, the first karyokinesis event is accompanied by the formation of a horizontal wall which divides the central cell into unequal regions. The larger one is the micropylear region and the smaller one is called chalazal region.
definition_reference: ISBN:0080374913

term: hydathode
id: GRO:0005660
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: ISBN:0080374913
definition_reference: GR:pj

term: hypodermis
id: GRO:0005051
definition: A layer or layers of cells beneath the epidermis that is derived from the ground meristem, but distinct in appearance from adjacent ground tissue. It is also the outermost layer or layers of cells in the stem or root cortex.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: intercalary meristem
id: pj:0006073
definition: The meristematic tissue separated from the apical meristem in the primary body by more or less mature tissues.
definition_reference: ISBN:0080374913
definition_reference: ISBN:0122151704

term: lacunar collenchyma
id: GRO:0005632
definition: A collenchyma characterized by intercellular spaces and cell wall thickenings facing the intercellular spaces.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: lamellar collenchyma
id: GRO:0005633
definition: A collenchyma in which cell wall thickenings are deposited mainly on tangential walls.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: lateral root apical meristem
id: pj:0006020
definition: Apical or primary meristem of the lateral root
definition_reference: GR:pj

term: laticifer
id: GRO:0005053
definition: A layer of cells forming a  secretory structure that produces latex
definition_reference: ISBN:0080374913

term: leaf abaxial epidermis
id: pj:0006019
definition: The epidermal layer present on leaf surface that is directed away from the axis or the internode above it.
definition_reference: ISBN:0080374913

term: leaf adaxial epidermis
id: pj:0006018
definition: The epidermal layer present on leaf surface that is directed towards the axis or the internode abopve it.
definition_reference: ISBN:0080374913

term: lysigenous aerenchyma
id: GRO:0005706
definition: Aerenchyma originating by dissolution of cells.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: meristem
id: PO:0009013
definition: Regions of a plant in which cells that have retained their embryonic characteristics, or have reverted to them secondarily, and that divide to produce new cells that can undergo differentiation to form mature tissues, i.e. they have a capacity for morphogenesis and growth.
definition_reference: APWeb:Glossary
definition_reference: GR:pj

term: meristem L1
id: PO:0009020
definition: The outermost layer of the shoot apical meristem which gives rise to the epidermis.
definition_reference: PMID:12221985
definition_reference: GR:pj

term: meristem L2
id: PO:0009021
definition: The cell layer beneath the L1 layer in the shoot meristem which gives rise to subepidermal tissue.
definition_reference: PMID:12221985
definition_reference: GR:pj

term: meristem L3
id: PO:0009022
definition: The multicellular layer beneath the L2 layer in the shoot meristem which gives rise to internal tissues of leaf and stem.
definition_reference: PMID:12221985
definition_reference: GR:pj

term: mesophyll
id: pj:0006070
definition: The chloroplast-containing, photosynthetic parenchymatous tissue situated between the two epidermal layers of the leaf or leaf like organs.
definition_reference: GR:pj

term: mesotome sheath
id: pj:0006025
definition: The inner endodermal sheath of a two layered bundle sheath. The cells are smaller in diameter compared to those in outer wall (starch sheath). The cell  walls are thick and contain suberized lamellae. They are analogous to endodermis.
definition_reference: ISBN:0080374913

term: metaphloem
id: pj:0006076
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: ISBN:0471245194

term: metaxylem
id: GRO: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 region
id: GRO:0000200
definition: The region of the endosperm closest to the micropyle of the ovule.
definition_reference: TAIR:lr

term: nectary epidermis
id: GRO:0000207
definition: the epidermal layer of the nectary.
definition_reference: TAIR:lr

term: nectary parenchyma
id: GRO:0000309
definition: Relatively unspecialized ground tissue present in the nectary.
definition_reference: TAIR:lr

term: oil gland
id: GRO:0005669
definition: A gland or a cavity lined with cells that secrete oils.
definition_reference: GR:pj

term: ovary epidermis
id: pj:0006063
definition: The epidermal cell layer of the ovary.
definition_reference: GR:pj

term: palisade parenchyma
id: GRO:0005648
definition: parenchyma characterized by elongated form of cells, that are closely packed and arrangement with their long axes perpendicular to the surface of the leaf.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: parenchyma
id: GRO:0005421
definition: Relatively unspecialized ground tissue composed of polyhedral cells with thin non-lignified cellulose cell walls and living protoplasts.
definition_reference: GR:pj

term: parenchyma sheath
id: pj:0006024
definition: Homologous to the endodermis, the parenchymatous single layered bundle sheath characterized by presence of large quantity of starch.
definition_reference: ISBN:0080374913

term: parenchyma spongy lower
id: GRO:0005836
definition: Present towards the leaf abaxial epidermis
definition_reference: ISBN:0471245194
definition_reference: GR:pj

term: parenchyma spongy upper
id: GRO:0005837
definition: Present below the palisade parenchyma in dorsiventral leaves
definition_reference: GR:pj
definition_reference: ISBN:0471245194

term: periderm
id: GRO:0005046
definition: Secondary protective tissue that replaces the epidermis in stems and root, rarely in other organs. 
definition_reference: ISSN:0669014893

term: peripheral zone
id: GRO:0000225
definition: organogenic region of the meristem. characterized by higher rates of cell division.
definition_reference: TAIR:lr
definition_reference: ISBN:0521288959

term: petal epidermis
id: pj:0006041
definition: The epidermal layer of the petal.
definition_reference: GR:pj

term: petal mesophyll
id: pj:0006071
definition: The chloroplast-containing, photosynthetic parenchymatous tissue situated between the two epidermal layers of the petal.
definition_reference: GR:pj

term: petal parenchyma
id: pj:0006069
definition: Relatively unspecialized ground tissue present in the petals.
definition_reference: GR:pj

term: petiole parenchyma
id: pj:0006066
definition: Relatively unspecialized ground tissue present in the leaf petiole.
definition_reference: GR:pj

term: phellem
id: GRO:0005049
definition: A protective tissue composed of nonliving cells with suberized walls and produced centrifugally by the phellogen
definition_reference: ISBN:0080374913

term: phelloderm
id: GRO:0005050
definition: A tissue resembling cortical parenchyma produced centripetally by the phellogen
definition_reference: ISBN:0080374913

term: phloem
id: GRO:0005417
definition: Food-conducting tissue that is found in vascular plants, composed mainly of sieve elements, parenchyma cells, fibers, and sclereids.
definition_reference: GR:pj

term: pith
id: GRO:0006109
definition: Ground tissue in the center of stem or root
definition_reference: ISBN:0080280307

term: plant structure
id: PO:0009011
definition: Any morphological or anatomical features of a plant.
definition_reference: Poc:curators

term: primary meristem
id: PO:0020144
definition: Meristem produced by the activity of the apical meristem.
definition_reference: APWeb:Glossary

term: primary phloem
id: pj:0006075
definition: The phloem of the primary plant body. In stem or root it is differentiated below or behind the apical meristem.
definition_reference: ISBN:0122151704

term: primary root apical meristem
id: pj:0006081
definition: Apical meristem of the primary root.
definition_reference: GR:pj

term: primary thickening meristem
id: GRO:0005039
definition: A meristem derived from the apical meristem and responsible for the primary increase in thickness of the shoot axis.
definition_reference: ISSN:0669014893
comment: May appear as a distinct mantle like zone. Often found in monocotyledons

term: primary vascular tissue
id: pj:0006078
definition: The vascular tissue of the primary plant body at the embryonic stage. 
definition_reference: GR:pj

term: primary xylem
id: GRO:0005849
definition: The xylem of the primary plant body or the primary meristem of the embryonic stage. In stem or root it is differentiated below or behind the apical meristem.
definition_reference: ISBN:0471245194
definition_reference: GR:pj
definition_reference: ISBN:0122151704

term: procambium
id: pj:0006074
definition: A primary cambium which undergoes differentiation to form the primary vascular tissue.
definition_reference: ISBN:0080374913

term: proliferation tissue
id: pj:0006087
definition: A tissue which develops from phloem parenchymain the outer portion of teh inner bark accomodating teh expansion in .
definition_reference: ISBN:0080374913

term: promeristem
id: GRO:0005752
definition: Meristematic tissue consisting of apical initials, together with cells derived from them and which are still close to the initial.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: protophloem
id: pj:0006077
definition: The first-formed elements of the phloem in a plant organ. First part of the primary phloem.
definition_reference: ISBN:0471245194

term: protoxylem
id: GRO: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
id: PO:0020149
definition: Hemispherically shaped aggregation of mitotically and metabolically inactive cells positioned behind the root cap.
definition_reference: ISBN:0-12-215170-4

term: resin canal
id: GRO:0005665
definition: A duct of schizogenous origin lined with resin-secreting cells (epithelial cells) and containing resin
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: rhexigenous aerenchyma
id: GRO:0005704
definition: Aerenchyma originating by rupture of cells.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: rhizodermis
id: pj:0006037
definition: The outermost cell layer of the primary root.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: rib zone
id: GRO: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 apical meristem
id: PO:0020147
definition: Apical, primary, meristem of the root
definition_reference: UMSL:fz

term: root cortex
id: GRO:0000258
definition: The primary tissue located between the vascular system and the epidermis.
definition_reference: ISBN:047125208
definition_reference: GR:pj
comment: In dicots and gymnosperms, the cortex consists of mainly parenchyma cells. In monocots sclerenchyma develops in addition to parenchyma.

term: root epidermis
id: pj:0006036
definition: The outer most cell layer of the the roots.
definition_reference: ISBN:0080374913
comment: The root epidermis is different from the shoot epidermis in its origin, function and structure.

term: root pith
id: GRO:0005040
definition: Ground tissue in the center of root
definition_reference: ISBN:0080280307

term: salt gland
id: GRO:0005661
definition: A specialized tissue or a storage site for the  excess salt absorbed in water from  the soil; help plants adapt to life in  saline environments
definition_reference: GR:pj
comment: A crust of salt forms on leaves  which tastes bad and the white  surfaces act to reflect light. Example, as is Mangrove vegetation

term: schizo-lysigenous aerenchyma
id: GRO:0005349
definition: Aerenchyma, originating by a combination of two processes, separation and degradation of cell walls.
definition_reference: ISBN:0080374913
definition_reference: GR:pj

term: sclerenchyma
id: GRO:0005427
definition: A supporting tissue composed of fibers or sclereids
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: scutellum epidermis
id: pj:0006049
definition: The epidermal layer of the scutellum.
definition_reference: GR:pj

term: secondary meristem
id: PO:0020145
definition: Cells that dedifferentiate and become meristematic.
definition_reference: APWeb:Glossary

term: secondary phloem
id: GRO:0005043
definition: The phloem tissue formed by the activity of the vascular cambium; part of the bark.
definition_reference: ISBN:0122151704

term: secondary vascular tissue
id: pj:0006080
definition: The vascular tissue derived from the vascular cambium because of the secondary growth.
definition_reference: GR:pj

term: secondary xylem
id: GRO:0005848
definition: The xylem tissue formed by the activity of the vascular cambium.
definition_reference: GR:pj
definition_reference: ISBN:0471245194
comment: It is absent in small dicot annuals and most monocots.

term: seed coat epidermis
id: pj:0006048
definition: The epidermal layer of the seed coat.
definition_reference: GR:pj

term: sepal epidermis
id: pj:0006040
definition: The outermost cell layer of the sepal.
definition_reference: GR:pj

term: sepal mesophyll
id: pj:0006072
definition: The chloroplast-containing, photosynthetic parenchymatous tissue situated between the two epidermal layers of the sepal.
definition_reference: GR:pj

term: sepal parenchyma
id: pj:0006068
definition: Relatively unspecialized ground tissue present in the sepals.
definition_reference: GR:pj

term: shoot apical meristem
id: PO:0020148
definition: Apical or the primary meristem of the shoot.
definition_reference: UMSL:fz

term: shoot epidermis
id: pj:0006035
definition: An outer layer of most of the shoot organs, often interrupted by stomata and other cell types.
definition_reference: ISBN:essau
definition_reference: GR:pj
comment: The shoot epidermis is different from the root epidermis in its origin, function and structure.

term: spongy parenchyma
id: GRO:0005647
definition: Leaf mesophyll parenchyma characterized by little elongated shape of cells, that are not closely packed and have conspicuous intercellular spaces.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: stamen filament epidermis
id: pj:0006060
definition: The epidermal cell layer of the stamen filament.
definition_reference: GR:pj

term: stem epidermis
id: GRO:0000112
definition: epidermal layer of the stem
definition_reference: TAIR:lr

term: stem hypodermis
id: GRO:0005057
definition: A layer or layers of cells beneath the stem epidermis that is derived from the ground meristem, but distinct in appearance from adjacent ground tissue. It is also the outermost layer or layers of cells in the stem cortex.
definition_reference: GR:pj
definition_reference: ISBN:0080374913

term: stem pith
id: GRO:0005041
definition: Ground tissue in the center of stem.
definition_reference: ISBN:0080280307

term: stigma epidermis
id: pj:0006061
definition: The epidermal cell layer of the stigma.
definition_reference: GR:pj

term: style epidermis
id: pj:0006062
definition: The epidermal cell layer of the style.
definition_reference: GR:pj

term: tissue
id: PO:0009007
definition: Group of cells organized into a structural and functional unit. Component cells may be alike (simple tissue) or varied (complex tissue).
definition_reference: TAIR:lr

term: transfusion tissue
id: pj:0006084
definition: A tissue consisting of tracheids and parenchyma cell, associated with the vascular bundle. Found generally in the gymnosperm leaves.
definition_reference: ISBN:0080374913

term: tunica
id: PO:0009023
definition: The outermost layer or layers in the shoot apical meristem of the Angiosperms in which the plane of division is almost anticlinal. This layer contrbutes to surface growth.
definition_reference: ISBN:0080374913
definition_reference: ISBN:0471245194

term: vascular cambium
id: GRO:0005598
definition: A secondary meristem, the cells of which give rise to secondary xylem and phloem, leading to an increase in stem girth
definition_reference: GR:pj

term: vascular tissue
id: PO:0009015
definition: Specialised conducting tissues made up of xylem and phloem. In the stem it is often found as a stele, surrounded by the cortex and inside which is the pith.
definition_reference: APWeb:Glossary

term: velamen
id: pj:0006042
definition: It is a multiseriate epidermis found in aerial roots of Araceae and Orchidaceae. Most of its cells are dead and store water like a sponge.
definition_reference: ISBN:0080374913

term: xylem
id: GRO:0005352
definition: vascular tissue whose principal function is the upward translocation of water and solutes; see also primary xylem or secondary xylem
definition_reference: GR:pj

