Terms : Hide Images
| 331327696 | axillary bud | a structure that has the potential to form a lateral shoot (branch) ; usually dormant | |
| 331327697 | terminal bud | makes up the shoot apex along with developing leaves and a compact series of nodes and internodes | |
| 331327698 | apical dominance | phenomenon in which the proximity of the terminal buds is partly responsible for inhibiting the growth of axillary buds | |
| 331327699 | epidermis | nonwoody plants; the single layer of tightly packed cells | |
| 331327700 | periderm | protective layer in woody plants that replace the epidermis in older regions of stems and roots | |
| 331327701 | xylem | vascular tissue that conveys water and dissolved minerals upward from roots into the shoots | |
| 331327702 | phloem | vascular tissue that transports organic nutrients such as sugars from where they are made to where they are needed | |
| 331327703 | stele | the collective term for the vascular tissue of a root or stem | |
| 331327704 | vascular cylinder | (in angiosperms) solid cylinder, the stele of the root | |
| 331327705 | vascular bundles | stele of stems and leaves divided into strands consisting of xylem and phloem | |
| 331327706 | pith | ground tissue internal to the vascular tissue | |
| 331327707 | cortex | ground tissue external to the vascular tissue | |
| 331327708 | parenchyma | cells that are relatively thin and flexible; has a large central vacuole; least specialized structurally; perform most of the metabolic functions of the plant, synthesizes and stores various organic products; retain ability to divide and differentiate into other types of plants | |
| 331327709 | collenchyma | cells that support young parts of the plant ; lack secondary walls; allow flexible support without restraining growth | |
| 331327710 | sclerenchyma | cells dead at functional maturity ; rigid walls that provide support and strengthening; have two types of cells (sclereids and fibers) | |
| 331327711 | sclereids | type of sclerenchyma ; shorter than fibers and irregular in shape | |
| 331327712 | fibers | type of sclerenchyma; usually arranged in threads; long, slender, and tapered | |
| 331327713 | tracheids | water-conducting cell of xylem; long, thin cells with tapered ends; water moves from cell to cell mainly through the pits (does not have to cross secondary walls) | |
| 331327714 | vessel elements | water- conducting cell of xylem; wider, shorter , thinner walled; end walls of vessel elements have perforations that enable water to flow freely through the vessels | |
| 331327715 | sieve tube members | chains of sieve cells that transport nutrients; lack nucleus, ribosomes and a distinct vacuole | |
| 331327716 | sieve plates | end walls between sieve tube members; have pores that facilitate the flow of fluid from cell to cell along the sieve tube | |
| 331327717 | companion cell | nucleus and ribosomes serve not only the cell itself but the adjacent sieve tube member; helps load sugars into the sieve tube members | |
| 331327718 | initials | cells that remain as sources of new cells | |
| 331327719 | derivatives | new cells displaced from the meristem | |
| 331327720 | primary plant body | parts of the troot and shoot systems produced by apical meristems during primary growth | |
| 331327721 | endodermis | innermost layer of the cortex; a cylinder one cell thick that forms the boundary with the vascular cylinder | |
| 331327722 | pericycle | outermost cell layer in the vascular cylinder where lateral roots arise from | |
| 331327723 | leaf primordia | finger-like projections along the flanks of the apical meristem | |
| 331327724 | palisade mesophyll | parenchyma; consists of one or more layers of elongated cells on the upper part of the leaf | |
| 331327725 | spongy mesophyll | parenchyma; cells are more loosely arranged which allows CO2 and O2 to pass through easier | |
| 331327726 | leaf traces | connections from vascular bundles in the stem; pass through petioles and into leaves | |
| 331327727 | bundle sheath | protective consisting of one or more layers of parenchymal cells that encloses the vein | |
| 331327728 | secondary plant body | consists of the tissues produced by the vascular cambium and cork cambium | |
| 331327729 | vascular cambium | adds secondary xylem and secondary phloem | |
| 331327730 | cork cambium | produces a tough, thick covering consisting mainly of cork cells | |
| 331327731 | fusiform initials | produce elongated cells such as tracheids, vessel elements and fibers of the xylem | |
| 331327732 | ray initials | produce vascular rays (radial files consisting mainly of parenchymal cells) | |
| 331327733 | heartwood | older layers of secondary xylem that no longer transport water and minerals; closer to the center of a stem or root | |
| 331327734 | sapwood | outer layers that still transport xylem sap | |
| 331327735 | lenticels | raised areas dotting the periderm that enable living cells within a woody stem or root to exchange gases with the outside air | |
| 331327736 | bark | all tissues external to the vascular cambium | |
| 331327737 | membrane potential | voltage; separation of opposite charges across a membrane; charge separation is a form of potential energy that can be harnessed to perform cellular work | |
| 331327738 | cotransport | mechanism in which a transport protein couples the downhill passage of one solute to the uphill passage to another | |
| 331327739 | chemiosmosis | transmembrane protein gradient ; links energy releasing processes to energy-consuming processes | |
| 331327740 | water potential | combined effects of solute concentration and physical pressure; moves from regions of higher to regions of lower | |
| 331327741 | solute potential | also called osmotic potential because solutes affect the direction of osmosis | |
| 331327742 | vacuolar membrane | also called a tonoplast; regulates molecular traffic between the cytosol and the vacuolar contents | |
| 331327743 | symplast | cytoplasmic continuum | |
| 331327744 | apoplast | continuum of cell walls plus the extracellular spaces | |
| 331327745 | bulk flow | movement of a fluid driven by pressure | |
| 331327746 | Casaparian strip | belt made of suberin (waxy material impervious to water and dissolved minerals) | |
| 331327747 | endodermis | innermost layer of cells in the root cortex; surrounds the vascular cylinder and functions as a last checkpoint for the selective passage of minerals from the cortex into the vascular tissue | |
| 331327748 | transpiration | the loss of water vapor from leaves and other aerial parts of the plant | |
| 331327749 | guttation | the exudation of water droplets when root pressure sometimes causes more water to enter the leaves than is transpired | |
| 331327750 | root pressure | an upward push of xylem sap | |
| 331327751 | sugar source | plant organ that is a net producer of sugar | |
| 331327752 | transfer cells | modified companion cells that enhance transfer of solutes between apoplast and symplast | |
| 331327753 | microspores | haploids formed when microsporocytes undergo meiosis; eventually give rise to haploid male gametophyte | |
| 331327754 | megaspores | haploid produced when megasporocyte undergoes meiosis | |
| 331327755 | double fertilization | ensures that the endosperm will develop only in ovules where the egg has been fertilized (prevents from squandering nutrients) | |
| 331327756 | endosperm | food-storing tissue of the seed from the triploid nucleus | |
| 331327757 | hypocotyl | embryonic axis | |
| 331327758 | epicotyl | portion of the embryonic axis where the cotyledons are attached | |
| 331327759 | coleoptile | sheath that covers the young shoot | |
| 331327760 | coleorhiza | sheath that covers the young root | |
| 331327761 | scutellum | specialized type of cotyledon that has a large surface area which absorbs nutrients during germination | |
| 331327762 | vegetative reproduction | asexual reproduction; mature fragments from the plant | |
| 331327763 | fragmentation | separation of a parent plant into parts that develop into whole parts that develop into whole plants | |
| 331327764 | apomixis | asexual production of seeds; no joining of sperm and egg; diploid cell in ovule gives rise to the embryo | |
| 331327765 | callus | mass of dividing, undifferentiated cells as a result of cutting | |
| 331327766 | etiolation | morphological adaptation for growing in the dark | |
| 331327767 | second messengers | small internally produced chemicals that transfer and amplify the signal from the receptor to other proteins that cause the response | |
| 331327768 | auxin | found in the embryo of seeds, meristems of apical buds, and young leaves; stimulates stem elongation, root growth, cell differentiation, branching; regulates development of fruit; enhances apical dominance; retards leaf abscission | |
| 331327769 | Cytokinins | synthesized in roots and transported to other organs; affect root growth and differentiation; stimulate cell division and growth; stimulate germination; delay senescence | |
| 331327770 | Gibberellins | meristems of apical buds and roots, young leaves, embryo; promote seed and bud germination, stem elongation, and leaf growth; stimulate flowering and development of fruit; affect root growth and differentiation | |
| 331327771 | brassinosteroids | seeds, fruit shoots, leaves, and floral buds; inhibit root growth; retard leaf abscission; promotes xylem differentiation | |
| 331327772 | abscisic acid | leaves, stems , roots , green fruit; inhibits growth, closes stomata, promotes seed dormancy | |
| 331327773 | ethylene | tissues of ripening fruit, nodes of stems, aging leaves and flowers; promotes fruit ripening, opposes some auxin effects; promotes or inhibits growth and development of roots, leaves and flowers |
