| A | B |
|---|
| vacuole | membrane bound vesicle used for storage or transport |
| parenchyma cell | spherical, thin-walled cell found throughout most plants that can function in photosynthesis, gas exchange, protection, storage, and tissue repair and replacement |
| collenchyma cell | often elongated plant cell that provides flexibility for the plant, support for surrounding tissues, and functions in tissue repair and replacement |
| sclerenchyma cell | plant cell that lacks cytoplasm and other living components when mature, leaving thick, rigid cell walls that provide support and function in transport of materials |
| meristem | region of rapid cell division in plants; produces cells that can develop into many different types of plant cells |
| vascular cambium | thin cylinder of meristematic tissue that produces new transport cells |
| cork cambium | meristematic tissue that produces cells with tough cell walls that form the protective outside layer on stems and roots |
| epidermis | dermal tissue that makes up a plant’s outer covering |
| guard cell | one of a pair of cells that function in the opening and closing of a plant’s stomata by changes in their shape |
| xylem | vascular plant tissue that transports water and dissolved minerals away from the roots throughout the plant and is comprised of vessel elements and tracheids |
| vessel element | elongated, tubular plant cell that forms xylem strands (vessels) and conducts water and dissolved substances |
| tracheid | long, cylindrical plant cell in which water passes from cell to cell through pitted ends |
| phloem | vascular plant tissue composed of sieve tube members and companion cells that conducts dissolved sugars and other organic compounds from the leaves and stems to the roots and from the roots to the leaves and stems |
| sieve tube member | nonnucleated, cytoplasmic cell of the pholem |
| companion cell | nucleated cell that helps mature sieve tube member function in transporting dissolved substance in the phloem of vascular plants |
| ground tissue | plant tissue consisting of parenchyma, collenchyma, and sclerenchyma |
| trichome | growth of hair |
| apical meristem | tissue at the tips of roots and stems that produces cells, which results in an increase in length |
| root cap | layer of parenchyma cells that covers the root tip and helps protect root tissues during growth |
| cortex | layer composed of ground tissues between the epidermis and a vascular tissue of a root |
| endodermis | cell layer at the inner boundary of the cortex; regulates the material that enters the plant’s vascular tissue |
| pericycle | plant tissue that produces lateral roots |
| petiole | stalk that connects a plant’s blade to the stem |
| palisade mesophyll | leaf tissue layer that contains many chloroplasts and is the site where most photosynthesis occurs |
| spongy mesophyll | loosely packed, irregularly shaped cells with spaces around them located below the palisade mesophyll |
| transpiration | process in which water evaporates from the inside of leaves to the outside through stomata |
| active transport | energy requiring process by which substances move across the plasma membrane against a concentration gradient |
| auxin | plant hormone that moves in only one direction away from the site where it was produced and can stimulate the elongation of cells |
| gibberellins | group of plant hormones that are transported in vascular tissue and that can affect seed growth, stimulate cell division, and cause cell elongation |
| ethylene | gaseous plant hormone that affects the ripening of fruits |
| cytokinin | plant hormone that promotes cell division by stimulating production of proteins required for mitosis and cytokinesis |
| nastic response | reversible, responsive movement of a plant that occurs independent of the direction of the stimulus |
| tropism | response to an external stimulus in a specific direction |
| mesophyll | middle leaf |
| spine | thin, pointed |
