| A | B |
|---|
| ABC model | identifying three classes of organ identity genes that direct formation of the four types of floral organs |
| adventitious | plant organ that grows in an atypical location |
| annual | plant that completes its entire life cycle in a single year or growing season |
| apical meristem | tissue in the tips of roots and shoots that supplies cells for the plant to grow in length |
| axillary bud | structure that has the potential to form a lateral shoot |
| bark | tissues external to the vascular cambium |
| biennial | plant that requires two years to complete its life cycle |
| blade | flattened portion of a typical leaf |
| bundle sheath | protective covering around a leaf vein |
| collenchyma cell | occurs in strands or cylinders that support young parts of the plant without restraining growth |
| companion cell | attached to a sieve-tube member by plasmodesmata |
| cork cambium | meristematic tissue in woody plants that replaces the epidermis with thicker |
| cortex | tissue that is between the vascular tissue and dermal tissue in a root or dicot stem |
| cuticle | waxy covering on the surface of stems and leaves that prevents desiccation |
| derivatives | cells that are displaced from an apical meristem and continue to divide until the cells they produce become specialized |
| dermal tissue system | outer protective covering of plants |
| determinate growth | growth stops after a certain size is reached |
| endodermis | cylinder one cell thick that forms the boundary between the cortex and the vascular cylinder |
| epidermis | dermal tissue system of nonwoody plants |
| fiber | lignified cell type that reinforces the xylem |
| fibrous root system | mat of thin roots spreading out below the soil surface in monocots |
| fusiform initials | cells within the vascular cambrium that produce elongated cells such as trocheids |
| ground tissue system | tissues that are neither vascular nor dermal (storage |
| guard cells | flank the stomatal pore and regulate the opening and closing of the pore |
| heartwood | inner older layers of secondary xylem that no longer transport xylem sap |
| herbaceous | nonwoody plants |
| indeterminate growth | continues to grow as long as it lives |
| initials | cells that remain within an apical meristem as sources of new cells |
| internode | segment of a plant stem between the points where leaves are attached |
| lateral meristem | thickens the roots and shoots of woody plants |
| lateral root | arises from the outermost layer of the pericycle of an established root |
| leaf | photosynthetic organ of vascular plants |
| leaf primordia | projections along the flanks of a shoot apical meristem |
| leaf trace | vascular bundle that extends from the vascular tissue of the stem through the petiole and into a leaf |
| lenticels | raised areas in the bark of stems and roots that enable gas exchange |
| meristem | tissue that remains embryonic as long as the plant lives |
| meristem identity gene | gene that promotes the switch from vegetative growth to flowering |
| mesophyll | tissue of a leaf |
| morphogenesis | development of body shape and organization |
| node | point along the stem of a plant at which leaves are attached |
| organ | specialized center of body function composed of several different types of tissues |
| organ identity genes | homeotic genes that use position to determine which leaves develop into floral organs |
| palisade mesophyll | One or more layers of elongated photosynthetic cells on the upper part of a leaf |
| parenchyma cell | unspecialized plant cell that carries out most of the metabolism |
| pattern formation | ordering of cells into specific three-dimensional structures |
| perennial | flowering plant that lives for many years |
| pericycle | outermost layer of the vascular cylinder of a root |
| periderm | protective coat that replaces the epidermis in plants during secondary growth |
| petiole | stalk of a leaf |
| phase change | shift from one developmental phase to another |
| phloem | living cells arranged into elongated tubes that transport sugar and other organic nutrients |
| pit | thinner region in the walls of tracheids and vessels where only primary wall is present |
| plasticity | parenchyma cells that form the central core of the vascular cylinder in monocot roots |
| polarity | differences in opposite ends of an organism or structure |
| positional information | signals indicating a cell’s location relative to other cells in an embryonic structure |
| preprophase band | microtubules in the cortex (outer cytoplasm) of a cell that are concentrated into a ring |
| primary growth | produced by apical meristems |
| primary plant body | tissues produced by apical meristems |
| protoplast | contents of a plant cell exclusive of the cell wall |
| ray initials | produce xylem and phloem rays |
| root | anchors the plant and enables it to absorb water and nutrients from the soil |
| root cap | cone of cells at the tip of a plant root that protects the apical meristem |
| root hair | tiny extension of a root epidermal cell increases surface area for absorption |
| root system | all of a plant’s roots that anchor it in the soil |
| sapwood | outer layers of secondary xylem that still transport xylem sap |
| sclereid | short irregular sclerenchyma cell in nutshells and seed coats |
| sclerenchyma cell | rigid supportive cell lacking protoplasts possessing thick secondary walls strengthened by lignin |
| secondary growth | produced by lateral meristems |
| secondary plant body | tissues produced by the vascular cambium and cork cambium |
| shoot system | aerial portion of a plant body |
| sieve plate | end wall in a sieve-tube member |
| sieve-tube member | living cell that conducts sugars and other organic nutrients in the phloem |
| spongy mesophyll | loosely arranged photosynthetic cells located below the palisade mesophyll cells in a leaf |
| stele | vascular tissue of a stem or root |
| stem | plant organ consisting of nodes and internodes that support the leaves and reproductive structures |
| stoma | microscopic pore surrounded by guard cells in the epidermis of leaves and stems that allows gas exchange |
| systems biology | approach to studying biology that aims to model the dynamic behavior |
| taproot system | system common to eudicots consisting of one large |
| terminal bud | tissue at the tip of a shoot |
| tissue | group of cells with a common function |
| tissue system | tissues organized into a functional unit connecting the organs of a plant |
| tracheid | cell that is dead at maturity and is found in the xylem of all vascular plants |
| vascular bundle | strand of vascular tissues (both xylem and phloem) in a stem or leaf |
| vascular cambium | cylinder of meristematic tissue in woody plants that adds layers of secondary vascular tissue |
| vascular cylinder | central cylinder of vascular tissue in a root |
| vascular tissue system | xylem and phloem ina vascular plant |
| vein | vascular bundle in a leaf. |
| vessel element | short wide, water-conducting cell found in the xylem |
| vessels | continuous water-conducting micropipes |
| xylem | dead cells that conduct most of the water and minerals upward from roots |
| zone of cell division | the root apical meristem and its derivatives. New root cells are produced in this region |
| zone of elongation | new cells elongate sometimes up to ten times their original length |
| zone of maturation | complete their differentiation and become functionally mature |
