Plant Form and Function: Exploring the Intricate Systems of Plant Anatomy and Physiology, Exams of Social Sciences

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root system - Answers-the entire set of plant roots that anchor the plant, absorb and transport minerals and water, and store food shoot system - Answers-the aerial portion of a plant body, consisting of stems, leaves, and (in angiosperms) flowers photosynthate - Answers-a sugar or other product of photosynthesis primary root - Answers-the first root (and organ) that emerges from a germinating seed lateral root - Answers-a root that develops from the pericycle of an established root taproot - Answers-a main vertical root that develops from the primary root (in eudicots) and gives rise to lateral roots; enables the plant to grow taller by preventing toppling node - Answers-a point along the stem of a plant at which leaves are attached internode - Answers-a segment of a plant stem between the points where leaves are attached apical bud - Answers-a bud at the tip of a plant stem; also called a terminal bud axillary bud - Answers-a structure that has the potential to form a lateral shoot or branch; appears in the angle formed between a leaf and a stem rhizome - Answers-a continuously growing horizontal underground stem which puts out lateral shoots and adventitious roots at intervals

USABO PLANT

FORM AND

FUNCTION

stolon - Answers-a creeping horizontal plant stem or runner that takes root at points along its length to form new plants tuber - Answers-an enlarged end of a rhizome or stolon that is specialized for storing food blade - Answers-the thin, flattened section of a plant leaf that collects sunlight petiole - Answers-the stalk of a leaf; joins the leaf to a node of the stem midrib - Answers-a major vein characteristic of eudicots that runs down the center of the blade of a leaf periderm - Answers-the protective coat consisting of the cork cambium and cork that replaces the epidermis in woody plants during secondary growth trichome - Answers-a small hair or other outgrowth from the epidermis of a plant; serves protective functions and prevents transpiration stele - Answers-the central core of the stem and root of a vascular plant, consisting of the vascular tissue and associated supporting tissue vascular cylinder - Answers-the central vascular core of a plant root vascular bundle - Answers-a strand of conducting vessels in the stem or leaves of a plant, typically with sclerenchyma fibers on the outside, phloem in the middle, and xylem on the inside pith - Answers-ground tissue internal to the vascular tissue cortex - Answers-ground tissue external to the vascular tissue parenchyma cell - Answers-(1) has a relatively thin and flexible primary cell wall (2) lacks a secondary cell wall (3) has a large central vacuole (4) produces sugars and stores starch (5) remains meristematic (6) is polyhedral in shape collenchyma cell - Answers-(1) is elongated (2) has an unevenly thickened primary cell wall (3) provides structural support without restraining growth (4) is living and flexible sclerenchyma cell - Answers-(1) has a thick, highly lignified secondary cell wall

(2) is unable to elongate (3) supports plant regions that have stopped growing (4) is dead at functional maturity primary growth - Answers-growth produced by apical meristems, lengthening stems and roots lateral meristem - Answers-a meristem that thickens the roots and shoots of woody plants (e.g. vascular and cork cambium) secondary growth - Answers-growth produced by lateral meristems, thickening the roots and shoots of woody plants vascular cambium - Answers-a cylinder of meristematic tissue in woody plants that adds layers of secondary vascular tissue cork cambium - Answers-a cylinder of meristematic tissue in woody plants that replaces the epidermis with thicker, tougher cork cells primary meristem - Answers-one of the three meristematic derivative of the apical meristem protoderm - Answers-the primary meristem that develops into dermal tissue procambium - Answers-the primary meristem that develops into vascular tissue ground meristem - Answers-the primary meristem that develops into ground tissue root hair - Answers-a tiny extension of a root epidermal cell, growing just behind the root tip and increasing surface area for absorption of water and minerals adventitious root - Answers-a root that grows from an unexpected region of the plant, such as from a stem or leaf; characteristic of a fibrous root system buttress root - Answers-a large, wide aerial root that provides architectural support to a shallowly-rooted tree prop root - Answers-an aerial, adventitious root that supports tall, top-heavy plants (e.g. maize) pneumatophore - Answers-an aerial root produced by mangroves and other swamp plants specialized for gaseous exchange stem - Answers-a vascular plant organ consisting of an alternating system of nodes and internodes that support the leaves and reproductive structures

root cap - Answers-a cone of cells at the tip of a plant root that protects the apical meristem; secretes mucilage, an extracellular polysaccharide that lubricates the soil around the tip of the root endodermis - Answers-in plant roots, the innermost layer of the cortex that surrounds the vascular cylinder pericycle - Answers-the outermost layer in the vascular cylinder, from which lateral roots arise apical dominance - Answers-the tendency for primary plant growth to be concentrated at the tip of the shoot, a property stemming from the inhibitory activity of the apical bud on axillary bud growth leaf primordium - Answers-a finger-like projection along the flank of a shoot apical meristem, from which a leaf arises mesophyll - Answers-leaf cells specialized for photosynthesis; in C3 and CAM plants, they are located between the upper and lower epidermis while in C4 plants, they are located between the bundle-sheath cells and the epidermis vascular ray - Answers-a radial file of mostly parenchyma cells that connects the secondary xylem and phloem; serves as a shuttle for water and nutrients heartwood - Answers-the dense inner part of a woody plant, consisting of older layers of secondary xylem sapwood - Answers-the soft outer layers of recently formed wood between the heartwood and the bark, consisting of functional secondary xylem bark - Answers-all tissues external to the vascular cambium, consisting of the secondary phloem and layers of periderm lenticel - Answers-a small raised area in the bark of woody stems and roots that enables gas exchange between the internal tissues and external environment meristem identity gene - Answers-a plant gene that promotes the switch from vegetative growth to flowering organ identity gene - Answers-a plant homeotic gene that uses positional information to determine which emerging leaves develop into which types of floral organs ABC hypothesis - Answers-a model of flower formation identifying three classes of organ identity genes that direct formation of the four types of floral organs; accounts for the phenotypes of mutants lacking A, B, or C gene activity, with one addition: where A gene activity is present, it inhibits C, and vice versa

calyx - Answers-the outermost whorl of sepals corolla - Answers-the second outermost whorl of petals androecium - Answers-the second innermost whorl of stamens gynoecium - Answers-the innermost whorl of carpels phyllotaxy - Answers-the arrangement of leaves on a stem specific to each species apoplast - Answers-in plants, everything external to the plasma membrane of a plant cell symplast - Answers-in plants, the continuum of cytoplasm connected by plasmodesmata between cells. water potential - Answers-the potential energy of water per unit volume relative to pure water in reference conditions; predicts the direction in which water will flow solute potential - Answers-a component of water potential that is inversely proportional to the molarity of the solution pressure potential - Answers-a component of water potential that quantifies the physical pressure on a solution; can be positive, zero, or negative Casparian strip - Answers-a water-impermeable ring of suberin (wax) in the endodermal cells of plants that blocks the passive flow of water and solutes into the stele by way of cell walls root pressure - Answers- guttation - Answers- cohesion-tension hypothesis - Answers- etiolation - Answers- auxin (IAA) - Answers-(1) promotes stem elongation via a proton-pump-mediated acid- growth mechanism (2) promotes fruit growth from developing seeds (3) indirectly enhances apical dominance (4) regulates vascular differentiation, spatial organization, and phyllotaxy (5) induces lateral/adventitious root formation in cuttings (6)serves as an herbicide at high concentrations by stimulating the production of ethylene

cytokinin - Answers-(1) stimulates cell division in developing tissues (2) represses apical dominance by promoting lateral bud growth (3) delays senescence by inhibiting protein degradation, stimulating RNA/protein synthesis, and mobilizing nutrients from surrounding tissues gibberellin (GA) - Answers-(1) promotes stem elongation, can induce "bolting" (2) stimulates fruit growth and seed germination (in response to imbibition) abscisic acid (ABA) - Answers-(1) inhibits growth (2) promotes seed dormancy and desiccation tolerance (3) reduces transpiration by inducing stomatal closure ethylene - Answers-(1) instigates the "triple response" in response to mechanical stress (2) enhances the rate of senescence and promotes leaf abscission (3) promotes ripening brassinosteroid - Answers-(1) promotes cell expansion and division in shoots (2) promotes root growth at low concentrations but inhibits root growth at higher concentrations (3) promotes xylem differentiation while repressing phloem differentiation (4) promotes seed germination and pollen tube elongation jasmonate - Answers-(1) regulate a wide variety of functions, such as fruit ripening, floral development, pollen production, tendril coiling, root growth, seed germination, and nectar secretion (2) plays important defensive roles in response to herbivory and infection strigolactones - Answers-(1) stimulate seed germination (2) suppress adventitious root formation (3) facilitate the establishment of mycorrhizal associations (4) repress lateral bud growth in response to auxin cryptochrome - Answers-a blue-light sensitive flavoprotein responsible for the light- induced inhibition of stem elongation in seedlings phototropin - Answers-a blue-light sensitive flavoprotein/kinase responsible for mediating stomatal opening, phototropism, and chloroplast movements phytochrome - Answers-a photoreceptor that responds to red and far-red light by stimulating and repressing seed germination respectively Pr - Answers-inhibits seed germination and stimulates vertical growth Pfr - Answers-stimulates seed germination and lateral branching and inhibits vertical growth

short-day plant - Answers-flowers when night exceeds a critical dark period; a flash of light interrupting the dark period prevents flowering long-day plant - Answers-flowers only if the night is shorter than a critical night period; a brief flash of light interrupting the dark period induces flowering