| A | B |
|---|
| meristematic tissue | plant tissue found only in the tips of shoots and roots; responsible for plant growth |
| apical meristem | group of undifferentiated cells that divide to produce increased length of stems and roots |
| epidermal cell | cell that makes up the dermal tissue which is the outer covering of a plant |
| cuticle | in plants, a thick, waxy layer on exposed outer surfaces of cells that protects them against water loss and injury |
| trichome | tiny cellular projection on the surfaces of some leaves that helps protect the leaf and also gives it a fuzzy appearance |
| vessel element | in angiosperms; xylem cell that forms part of a continuous tube through which water can move |
| sieve tube element | phloem cell that is joined end-to-end to similar cells to form a continuous sieve tube |
| companion cell | phloem cell that surrounds sieve tube elements |
| parenchyma | type of ground-tissue cell with a thin cell wall and large central vacuole |
| collenchyma | type of ground tissue cell with a strong, flexible cell wall; helps support larger plants |
| sclerenchyma | type of ground-tissue cell with an extremely thick, rigid cell wall that makes ground tissue tough and strong |
| taproot | primary root found in some plants that grows longer and thicker than other roots |
| fibrous root | part of a root system in which roots branch to such an extent that no single root grows larger than the rest |
| root hair | tiny projection from the outer surface, or epidermis, of a root |
| cortex | spongy layer of ground tissue just inside the epidermis of a root |
| endodermis | layer of cells that completely encloses vascular tissue |
| vascular cylinder | central region of a root that includes the vascular tissue - xylem and phloem |
| root cap | tough structure that protects a root as it forces its way through the soil |
| Casparian strip | waterproof strip that surround plant endodermis cells |
| node | point on a stem where a leaf is attached |
| internode | region between nodes on plant stems |
| bud | plant structure containing undeveloped tissue that can produce new stems and leaves |
| vascular bundle | plant stem structure that contains xylem and phloem tissue |
| pith | parenchyma cells inside the ring of vascular tissue in dicot stems |
| primary growth | type of plant growth that occurs at the tips of roots and shoots |
| secondary growth | pattern of plant growth in which stems increase in width |
| vascular cambium | lateral meristematic tissue that produces vascular tissues and increases the thickness of the stem over time |
| cork cambium | lateral meristematic tissue that produces the outer covering of stems |
| heartwood | older xylem near the center of a woody stem that no longer conducts water |
| sapwood | area in plants that surrounds heartwood and is active in fluid transport |
| bark | tree structure that includes all tissue outside the vascular cambium, including phloem, the cork cambium, and cork |
| blade | thin, flattened section of a plant leaf that collects sunlight |
| petiole | thin stalk by which a leaf blade is attached to a stem |
| mesophyll | specialized ground tissue that makes up the bulk of most leaves; performs most of a plant's photosynthesis |
| palisade mesophyll | layer of tall, column-shaped mesophyll cells just under the upper epidermis of a leaf |
| spongy mesophyll | loose tissue beneath the palisade layer of a leaf; has many air spaces between its cells |
| stomata | opening in the underside of a leaf that allows carbon dioxide and oxygen to diffuse into and out of the leaf |
| guard cell | specialized cell in the epidermis of plants that controls the opening and closing of stomata by responding to changes in water pressure |
| transpiration | loss of water from a plant through its leaves |
| adhesion | attraction between unlike molecules |
| capillary action | tendency of water to rise in a thin tube |
| pressure-flow hypothesis | hypothesis that considers plants in terms of where they produce and use material from photosynthesis |
