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97 Cards in this Set
- Front
- Back
angiosperms |
-most diverse in regards to shape, size habitats, growth habitats, and nutrition modes -freeliving photosythesizers -evolution of flower and fruit (reproductive adaptations) - evolved efficient mechanism of transferring pollen from male to female reproductive parts--Pollinators |
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monocot |
embryo has single seed leaf called cotyledon ex: grasses, palms and orchids - 3 floral parts -leaf veins are parallel -one pore in furrow of pollen grain surface -vascular bundles disturbed throughout ground tissue -branching fibrous root system |
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eudicot |
has two cotyledons ex: angiosperms trees and shrubs -more diverse than monocots - usually 4 or 5 floral parts - leaf veins in netlike array -three pores or furrow in pollen grains -vascular bundles organized in ring around tissues -main taproot with smaller lateral roots |
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basal angiosperms |
-earliest branches of flowering plant lineage |
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Flower |
- a reproductive shoot that contains organs for sexual reproduction -arose as natural selection modified Sporophylls (leaves) 4 organs: Carpel: center where female gamtopyrtes form -includes ovary that shelters ovules -includes stigma at tip of style: that provides landing platform for pollen grains Stamens: where male gametophytes form -consists of stalk like filament -capped by anther -each anther contains four pollen sacs Petals: slowly leaf like structure with distinctive patterns and shape to attract pollinators Sepals: green, enclose all other parts in bud |
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Double fertilization |
-gives rise to embryo and enhanced food supply for it in form of nutritive tissue called endosperm 1. flowering stem of mature sporophyte (2n) 2. meiosis gives rise to 4 megaspores, all but one disintegrate. (haploid) 3. megaspore undergoes mitosis without cytokinesis forming a single large cell with 8 nuclei 4. Cytokinesis produces a female gametophyte that consists of seven cells -one cell becomes egg, while another large cell (2 nuclei_ become endosperm (nutrition) -rest of cells disintegrate (haploid) 5. pollen is released 6. pollination occurs, pollen grain develops pollen tube that grows toward ovary. The tube contains two sperm and is the mature gametophyte 7. pollen tube enters ovule, one sperm fertilizes egg while the other will fertilize the bionucleate endosperm 8. double fertilization produces trinucleate cell that gives rise to triploid endosperm- which nourishes the developing embryo (2n) 9. eventually a seed may germinate and grow into a seedling that in turn grows into a mature sporophyte (2n) |
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fruit |
-ovary develops into fruit, that encloses the angiosperm seed within. -it protects a seed and the embryo -and it helps disperse seed |
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Chapter 33: The plant body |
see below |
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seed plants |
root system: undergound shoot system: above ground |
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organs |
systems consist of organs- structures that contain two or more types of tissues and have definite form and function include: roots, leaves, stems and in angiosperms flowers and fruit |
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tissue |
- a group of cells and intercellular substances that function together in one or more specialized task |
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Plant organs are built off of three tissue systems |
see below |
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1. ground tissue system |
-makes most of primary plant body -imcludes tissues that function in photosynthesis, storage and support |
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2. Vascular tissue system |
- consists of interconnecting cells that form transport channels throughout plant Xylem tissue: transports water Phloem tissue: transports nutrients |
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3. Dermal tissue system |
-serves as skin like protection covering for plant body |
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root system |
- grows below ground - anchors the plant and provides structural support for above ground parts -absorbs water and dissolved minerals from soil -stores carbohydrates |
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shoot system |
- a series of repeating components such as stems, leaves and buds -highly adapted for photosynthesis leaves: organs that increase plants SA stems: position leaves for max light exposure in angiosperms leaves position flowers for max pollination |
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buds |
-embryonic shoots that give rise to leaves, flowers, or both |
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determinate growth |
growth slows or stops once organism reaches certain size. ex: animals -in plants, occur in leaves, flowers and fruit |
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indeterminate growth |
-meristem are basis for indeterminate growth -give plants structural and functional flexibility or plasticity, allowing for responses to changed environments such as light, temp, water, and supply of nutrients |
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meristem |
-clumps of self-perpetuating embryonic tissue -produce more or less tissue continuously as plant is alive -are totipotent: having the genetic capacity to give rise to new tissues and a new plant |
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meristem |
-responsible for both height and girth - |
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apical meristem |
-produces an increase in length -at tips of buds, stems, and roots -primary tissues develop and make up primary plant body, growth from these primary tissues is called primary growth |
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lateral meristems |
-self perpetuating cylinders of tissue -resonsiible for secondary growth of trees and shrubs with woody body -secondary tissues develop, that make up the woody secondary plant body |
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secondary growth |
-increases growth of older roots and stems - produces woody tissue - requires investment of energy and resources corrleting to long life and repeated opportunities for reproduction -Eudicots have secondary growth |
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monocots |
-no secondary growth - herbaceous species: mature and reproduce quickly which small investment of energy and resources divided into annuals, biennial and perennials |
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simple tissues |
only one type of cell |
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complex tissues |
-organized arrays of two or more cell types |
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cellulose rich primary wall |
-developed in all newly forming plant tissues -wall forms around protoplast, a plants cells cytoplasm, organelles, and plasma membrane -in some cells, protoplasts of various types of cells deposit additional cellulose and lignin inside primary wall to form secondary wall that makes up vascular tissue xylem |
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Ground tissues |
- bulk of plant organs -cells are working bees carrying out photosynthesis, storing carbohydrates or water, and provided mechanical support for plant body |
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1. parenchyma |
-soft primary tissues of ground tissue - only thin primary wall with no ligin, so they are more pliable or permeable to water -relatively unspecialized -photosynthesis occurs in parenchyma cells where a large number of chloroplasts develops -somtimes they are specialized for short distance transport of solutes - are alive and capable of dividing, mitotic divisions produced new cells that heal wounds of plant parts |
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2 Collenchyma |
-flexible support -cells are elongated -forms strands of sheath like cylinder within growing shoot regions and the stemlike petiole at base of leaf -are alive at metabolically active as they mature - important adaption in elongation of stems that need structural support -each collenchyma cell develops only a primary wall built of layers of cellulose and pectin and over time it thickens |
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3. Schlerenchyma |
-rigid support and protection -only in mature plant parts -cells of this type develop thick secondary wall that become heavily lignified. once cell is encased in ligin it dies because its protoplast can no longer take up nutrients or exchange base. but it still provides protection and support for life two types schlereids: variety of shapes -give texture and form thick protective coat Fibers: elongated schel. cells that are resistant to stretching |
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Vascular tissues |
-specialized for conducting tissues -composed of complex tissues of specialized conducting cells, parenchyma cells, and fibers two types of tissues that arrose xylem and phloem: tissues organized in bundles of interconnected cells that extend throughout plant |
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Xylem |
-transports water and minerals from root to shoot- Transpiration -key adaption in early land plant evolution because it provided means for distributing water and provided support for upright growth Contains 4 types of cells with these functions: parenchyma, fibers, conducting cells, and tracheas and vessel elements -when conducting cells reach maturity they lay down secondary cell walls thickened with ligin and cellulose, the cell protoplast, dies leaving pipelines for water and minerals |
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Tracheids |
-elongated cells with narrow diameter that overlap -water moves from cell to cell through pits and so water seeps from tracheid to tracheid -in forerunners of modern plant species -still only in ferns, gymnosperms and basal angiosperms |
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vessel elements |
-joined end to end in multicellular columns called vessels -wider diameter Tham tracheids to enhance water flow -as they mature, enzymes break down portions of their end walls producing perforations -perforations suggest process is under genetic control -in angiosperms of today provide adaptive advantage by increasing efficiency with which water and mineral move throughout body |
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Xlyem |
-cotaines parenchyma cells and sclerenchyma fibers parenchyma cells: help transport minerals through vessel elements and tracheids Sclerenchyma fibers: function like steal cables, helping keep xylem tissue rigid |
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Phloem |
-tissue that transports sugars made in photosynthesis and other solutes -main conducting cells are sieve tube elements: which connect end to end forming a sieve tube |
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companion cells |
-specialized parenchyma cells -connected to mature sieve-tube elements by plasmodesmata -assist sieve tube elements both with uptake of sugar and with unload of sugars in tissues that are growing or storing food |
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Dermal tissues |
-protect plant surfaces -epidermis: covers primary plant body |
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cuticle |
surface cells of shoot system secret a cuticle -a way coating that fends of water loss and attack microbes |
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Trichomes |
-outgrowths of epidermis -some exude sugars that function to attract pollinators -some produce chemicals designed to deter predators ex: Root hairs:form from outer wall of epidermal cells and absorb much of plants water and minerals from soil |
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Stromata |
- porelike openings present in the epidermis of leaves , young stems, slower parts and some roots -situated in between specialized epidermal cells called guard cells, that open and close -carbon dioxide for photoysnthesis enters plants through open stomata, while water vapor and and oxygen exit -genes control regulation of stomata YODA: where and how many stomata form -plants can also reduce or increase their number of stomata in response to external co2 levels |
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root systems |
- plants must absorb water and dissolved minerals to sustain growth and routine cellular maintenance, which requires a large root surface area -the roots of carrots, sugars and beets store nutrients produced in photosynthesis, some are used by root cells and some are transported later to cells of the shoot. |
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eudicots |
-taproot system: a single main root that is adapted for storage and smaller branching roots called lateral roots ex: carrots and dandelions, conifers and some angiosperm trees |
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monocots |
- first, embryonic root (radicle) dies and its role is assumed by the adventurous roots that arose from stem -adventurous roots eventually form a fibrous root system, in which several main roots branch to form a dense mass of smaller one |
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fibrous root systems |
-monocots -adapted to absorb water and nutrients from upper layers of soil, and tend to spread out laterally from the base of the stem -important ecologically because dense root networks help hold topsoil in place and prevent erosion |
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Adventurous roots |
-in monocots -can also arise from leaves or other shoot parts. ex: prop roots of corn plant, that develop from the shoot node nearest the soil surface -they support the plant and absorb water and nutrients ex: Buttress roots variations on prop root theme |
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pneumatophores |
-aboveground roots -mangroves and other trees that grow in marshy habitats |
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storage root |
- a lateral root that stockpiles nutrients that can sustain new shoot parts during diff growing seasons ex: sweet potato |
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Root structure is specialized for underground growth |
-primary growth of root begins when an embryonic root emerges from a germinating seed and its meristems become active |
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root cap |
-made of meristem, which surrounds and protects meristem as the root elongates through the soil -apical meristem terminates in root cap -cells here respond to gravity, guiding root tip downward -cap also secretes polysaccharide rich substance that lubricates tip and eases the passage through soil -outer root cap cells are continuously abraded off and replaced |
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Primary growth in roots |
-takes place in many stages, beginning at root tip and processing upward |
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quiescent center |
-small clump of apical meristem cells that is inside root cap -cells here divide slowly unless root cap or apical meristem in injured, when they become active to regenerate damage -this center may also include cells that synthesize plant hormones that control root development |
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zone of cell division |
- root apical meristem and the activity dividing cells behind center -here rapidly dividing cells of the root apical meristem segregate into three layers Procambium: cells in the center of the root Ground Meristem:outside procambium Protoderm: outside -this zone emerges into the zone of elongation |
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zone of elongation |
- increase in roots length occurs here as cells become longer and their vacuoles fill with water -this hydraulic elongation pushes the root cap and apical meristem through the soil |
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zone of maturation |
-above zone of elongation where cells no longer increase in length but differentiate further and take on specialized roles ex: epidermal cells give rise to root hairs |
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Tissues of root system |
-primary root growth produces unified system of vascular pipelines extending from root tip to shoot tip. -root pro cambium produces cells that mature into roots xylem and phloem -Ground meristem gives rise to roots cortex, and its ground tissue of starch-storing parenchyma cells that surround the stele |
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Stele |
-xylem and phloem tissue - in eudiocots, stele runs through center of root -in monocots, stele forms ring that divides ground tissue into cortex and pith |
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Monocot stele |
-a ring -cortex: contains air spaces that allow for oxygen to reach all of the living root cells -numerous plasmodesmata connect cytoplasm of adjacent cells of the cortex -in flowering plants, outer root cortex, rives rise to exodermis, a narrow band of cells beneath the epidermis |
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exodermis |
-in flowering plants, a narrow band of cells beneath epidermis - may limit water loses from roots and help regulation absorption of ions. |
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endodermis |
- innermost layer of root cortex - a thin selectively permeable barrier that helps control the movement of water and dissolved minerals into the stele |
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pericycle |
-between stele and endodermis -consisting of more layers of parenchyma cells that can still function as meristem -gives rise to lateral roots -in response to chemical growth regulators, rudimentary roots or root primordial, arise at specific sites in the pericycle -gradually lateral roots energy and grow out through cortex and epidermis, aided by enzymes released by root primordium |
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trichomes |
-root hairs - outer surface of developing root epidermis -increase plants absorptive surface -each is slender tube with thin walls made of sticky coating of pectin, which soil particles tend to adhere to |
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Primary shoot systems |
-consiste of main stem and leaves |
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stems |
- incorporate evolution adaptions that serve 4 functions 1. stems provide mechanical support, along vertical axis, for body parts like leaves and flowers 2. stems house the vascular tissues xylem and phloem, which transport water, dissolved minerals, hormones, and products of photosynthesis 3. stems often have modifications for storing water and food 4. buds and specific stem regions contain meristem tissue that gives rise to new cells of the shoot - a set of modules |
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stem modules |
- node- where one or more leaves attach to a stem -internode: area between two nodes axil: upper angle between stem and attached lead |
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buds |
-where new primary growth occurs -terminal bud: at apex of each stem -Lateral bud: in leaf axils that produce new branches or shoots that give rise to flowers |
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stem growth |
-occurs in apical meristem as internode cells divide and elongate. -most active at apex Monocots: upper cells of internode stop dividing as it elongates, and division is limited to meristamtic region at the base of the internode ex: grasses |
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Terminal buds |
- at tip of shoot -release hormone that inhibits growth of nearby lateral buds, called apical dominance |
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shoot primorda |
- made by shoot apical meristem - primordial are bulges that are the first developmental stages of leaves, additional shoots, and reproductive structures |
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shoot apical meristem |
- a dome shaped mass of cells -when it divides, one of the daughter cells becomes an initial, that remains part of the meristem. -the other daughter cell becomes a derivative, which is the source for specialized cells. -in this way, division replenishes initials of meristem and provides derivative that result in plant growth |
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Derivatives |
- give rise to three primary meristems, which each occupies a different place in the shoot tip - these meristems are unspecialized and produce cells that give rise to specialized cells and tissues. 1. protoderm- outermost, produces stems epidermis cells including guard cells and trichomes 2. Ground meristem- gives rise to ground tissue, mostly parenchyma 3. Procambium- produces primary vascular tissues that exist in threadlike strands of cells within ground meristem -inner probambium cells give rise to xylem -outter pro cambium cells give rise to phloem |
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plants with secondary growth |
- a thin region of the pro cambium between primary xylem and phloem remains undifferentiated, which will give rise to lateral meristem |
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vascular bundles |
- multistranded cords of primary xylem and phloem, wrapped or capped in sclerencym -the bundles thread lengthwise through parenchyma, forming stele. -the stele, runs vertically and the ground tissue outside of it forms the cortex, while the inside is the pith |
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Cortex and pith |
-are mainly parenchyma, and in some plants the pith stores starch -in Monocots, vascular bundles are dispersed through ground tissue so separate cortex and pith sections do not form. |
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stem modifications |
-stem tubers:stem regions enlarged by the presence of starch storing parenchyma cells ex: white potato -rhizome: starchy root of ginger - corms: fleshy underground stems -all tubers, rhizomes and corms have meristematic tissue at nodes from which plants can be propagated -stolons: slender stems that allows strawberries to reporoduce asexually too thorns: stems modified to deter predication caci: help sustain plant during dry periods |
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Leafs |
- main sites of photosynthesis - permit plant gas exchange and limit the loss of water by evaporation angiosperm leaf structure blade: provides large surface area for absorbing sunlight and carbon dioxide -in eudicot leaves, bad narrows to form petiole -monocot leaves have no petiole and blade is long and narrow -conifers: leaves are scalelike or needlelike and have sunken stromata and thicken cuticle adaptions for arid environments |
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leafs |
simple leaves: have single blade compound: divided into smaller leaflets |
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leaf primordium |
- leaves develop on sides of shoot apical meristem - initially meristematic cells near the apex divide and their derivative elongate, the resulting bulge develops into a leaf primordium -as plant grows and internodes elongate, leaves that form leaf primordium become spaced at intervals along stem |
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leaf tissues |
-have seven layers epidermis: uppermost, with cuticle covering surface mesophyll: just below, a ground tissue composed of loosely packed parenchyma cells that contain chloroplasts eudicots: contain two layers of mesophyll. palisade mesophyll cells: contain more chloroplasts and arrange in compact columns with air spaces and spongy mesophyll- located on the underside of the leaf, which consists of irregularly arrange cells with air spaces that give spongy appearance air spaces in mesophyll- enhance uptake of CO2 epidermal layer: below mesophyll, -cuticle covered except in grasses and other plants, this layer contains most of the stomata, through which water vapor exits the leaf and cO2 enters |
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veins |
-formed by networks of vascular bundles Eudicot: branching vein pattern monocots: veins run in parallel arrays |
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juvenile phase |
-plants that live many years, may spend part of their lives in juvenile phase -juvenile phase and adult phase are reflected in the arrangement of leaves on the stem, or the change in vegetative growth to a reproductive stage. -phase changes provide example of plasticity and are associated with changes in the expression of genes that control development of the stem nodes, leaf and flower buds and other basic developments |
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Secondary growth |
- tissues we know as wood and bark add girth to the roots and stems over two more more growing seasons -mitosis is reactivated in two types of lateral meristems, their activity makes older stems and roots more massive 1. vascular cambium: produces secondary xylem and phloem 2 cork cambium: a secondary epidermis that produces cork a major ingredient of bark cork walls contain waxy substance Suberin,that makes them waterproof |
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secondary growth |
- as woody plant completes primary growth, each vascular bundle contains a layer of undifferentiated cells between the primary xylem and phloem -this cells give rise to a cylinder of vascular cambium that encircles the xylem and pith of stem |
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vascular cambium |
- two types of initials -secondary growth takes place mainly as these cells divide in a plane parallel to vascular cambium, adding girth to the stem -one type of initials, give rise to secondary xylem and phloem, that conduct fluid vertically through stem. -secondary xylem, forms inner face of vascular cambium and secondary phloem forms on the outer face. -other initials produce rays, horizontal columns of parenchyma cells arranged like spokes of a wheel. |
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ray parenchyma |
- stores carbohydrates or helps move solutes horhzatonally across the stem |
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secondary xylem |
- with time a great deal of secondary xylem forms inside ring of vascular cambium. -this is wood -the primary phloem cells, with thin walls are destroyed as they are pushed out by secondary growth. So each year some secondary phloem is added each year. |
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cork |
- as stems diameter increases, the enlarging mass of new tissue ruptures the cortex causing parts to slit away and carry epidermis with them - cork cambium replaces the lost epidermis with cork |
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Bark |
-consists of tissues sandwiched between vascular cambium and the stem surface. -the bark includes the secondary phloem, and the periderm( cork, cork cambium, and secondary cortex) |
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Tubular openings (lenticels) |
-develop in periderm -they permit exchanges of cO2 between living tissues and outside air. |
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heartwood |
-center of older stems and roots -dry tissue that no longer transports water and solutes -storage depot for defensive compounds -in time these compounds, resins, oils, gums and tannins, clog and fill the oldest xylem pipeline darkening it and making aromatic and resistant to decay |
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sapwood |
-located between heartwood and vascular cambium - it is wet and functions in water transport and is not as strong |
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Secondary growth in roots |
-not in monocots - the continuous ring of vascular cambium develops differently than it does in stems -when primary growth is done, roots have layer of residual pro cambium between xylem and phloem of stele. - vascular cambium arises from this residual cambium and in part of the pericycle -formed vascular cambium gives rise to secondary xylem (inside) and phloem (outside) cork cambium, also forms in roots, where it is produced by pericycle and later by initials in secondary phloem |
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periderm |
in woody eudicots, and gymnosperms, most of the root epidermis and cortex fall away and the surface consists of periderm |
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primary and secondary growth |
-development of new tissues and organs maintains a balance between shoot system and root system (with hormones) Leaves: and other photosynthetic parts of shoot supply root cells with enough sugars to support their metabolism Roots: must provide shoot structure with water and minerals |