| Adventitious roots |
Roots that emerge from the stem rather than roots. |
| Anthocyanin pigments |
Red pigments that are produced primarily in the autumn in response to bright light and excess plant sugars in leaf cells. |
| Apical meristem |
Group of more or less continually dividing cells located at the tip of a shoot or root. |
| Axillary bud |
Bud borne in the axil of a stem. |
| Axillary meristem |
Group of more or less continually dividing cells located at the axils of a stem. |
| Cambium |
Lateral meristem in vascular plants, including the vascular cambium and cork cambium, that forms parallel rows of cells resulting in secondary tissues. |
| Carotenoid pigments |
Yellow and orange pigments that are present in the leaf all growing season, but during the warm part of the season these colors are hidden by the high concentration of green-colored chlorophyll. They take longer to break down than chlorophyll. |
| Cortex |
Also known as the ground meristem, is found just inside the epidermis and extends toward the interior of the stem and root, and is made up of three types of cells: parenchyma, collenchyma, and sclerenchyma. |
| Crown |
Compact stem tissue at or near the soil surface. |
| Cuticle |
Protective waxy coating of cutin on epidermis cells that restricts water loss. |
| Cutin |
Water-resistant substance that coats the wall of the cell exposed to the environment and helps limit the loss of water that is inside of the plant to the atmosphere. |
| Dicotyledon (dicot) |
Seed plant that produces an embryo with paired cotyledons, floral organs arranged in cycles of four or five, and leaves with net-like veins. |
| Fibrous root |
Root system where the radicle grows and then rapidly slows or completely halts in growth. Once this happens roots will emerge above the radicle and from the stem tissue located below the soil. |
| Gravitropism |
Growth in response to gravity. |
| Guard cells |
Located on the epidermis and regulate the size of the stomata. |
| Herbaceous |
Plants whose above-ground parts die back to the soil surface at the end of the growing season. |
| Herbaceous annual |
Plants that completely die over winter. These plants complete their life cycle from seed to flower to seed in one year. |
| Herbaceous perennial |
Plants where only the above-ground growth dies over winter. The underground portion lives for more than two growing seasons (two years). |
| Mitosis |
Cell division where a cell divides into two identical daughter cells. |
| Monocotyledon (monocot) |
Seed plant that produces an embryo with a single cotyledon and parallel-veined leaves; includes grasses, lilies, palms, and orchids. |
| Phloem |
Tissue consisting of sieve tube and companion cells in the vascular system of plants that moves dissolved sugars and other products of photosynthesis from the leaves to other regions of the plant. |
| Pith |
Occupies the central part of the stem and is composed of thin-walled parenchyma cells often with larger intercellular spaces than you would find in the cortex. |
| Primary root |
Root that forms from the embryonic radicle. |
| Procambium |
New cells in the central part of the root that will mature to become the vascular tissue (xylem, phloem, and vascular cambium). |
| Protoderm |
New, primarily epidermis, cells laid down toward the exterior of the root which will mature to become the root dermal tissue. |
| Root cap |
Thimble-shaped mass of cells that covers and protects the root apical meristem from rocks, dirt, and pathogens. |
| Secondary growth |
Production of xylem and phloem from cambium cells. |
| Secondary root |
Root that forms off of the primary root. |
| Statocytes |
Specialized cells that help the plant to sense gravity and grow accordingly. |
| Stomate/Stoma/Stomata |
Gap in the epidermis that allows gas exchange between the atmosphere and internal parts of the leaf. |
| Tap root |
Main root of a plant, usually stouter than the lateral roots and growing straight downward from the stem. |
| Translocation |
Movement of a substance from one place to another. |
| Trichome |
Either unicellular or multicellular hair-like outgrowths arising from the epidermis; found on stems. |
| Vascular bundle |
System containing vessels that carry or circulate fluids and dissolved minerals in the plant; composed of xylem, phloem, and bundle sheath cells. |
| Xylem |
Supporting and water-conducting tissue of vascular plants. |
| Zone of Differentiation |
Area in roots where tissues are formed (expand in width). |
| Zone of Elongation |
Area in roots where recently produced cells grow and elongate prior to differentiation. |
