Chapter 4: Terms
Here are the terms from this week’s lessons that you will need to be familiar with for your assignments and for the quiz.
| Abscisic acid | A hormone that regulates seed maturation and responses to changes in water availability. |
| Adventitious root | A root that emerges from anywhere on the plant other than from the roots. |
| Angiosperms | A group of flowering plants whose seeds develop inside an ovary. |
| Annual plant | A plant that is produced from seed in the spring and dies at the end of the growing season. |
| Apical dominance | Where a shoot suppresses growth of floral or vegetative axillary buds below the growing point. |
| Auxins | A group of related hormones that regulate many aspects of plant growth and development and are key to stimulating adventitious rooting. |
| Competency | The ability to respond to a signal, such as a plant hormone. |
| Compound inflorescence | An inflorescence with a group of flowers and includes a rachis. |
| Cytokinins | A group of related molecules that regulate cell division and are key to stimulating adventitious shoot formation. |
| Determinate | When the stem of a plant terminates in a flowering stalk and new stem growth continues from subterminal lateral buds. |
| Endogenous hormone | A hormone that occurs within the plant. |
| Ethylene | A gas that regulates fruit ripening and plant senescence. |
| Exogenous hormone | The application of a hormone to a plant. |
| Floret | A single flower in a compound inflorescence. |
| Flower | A reproductive structure in a flowering plant. |
| Gibberellins | A group of related molecules that regulate seed dormancy. |
| Gymnosperms | A group of plants whose seeds are produced without the protection of an ovary. |
| Indeterminate | When the apical meristem remains a vegetative meristem capable of forming new nodes and internodes throughout the season. Once the hormonal signals are right, reproductive axillary meristems at the nodes below the apical meristem produce inflorescences. |
| Inflorescence | The complete flower structure of a plant; includes the flower, pedicle, rachis, and peduncle. |
| Natural hormone | A hormone made by a plant. |
| Pedicel | The short stalk that holds up the flower. |
| Peduncle | The large, central stalk that attaches the rachi to the stem of the plant. |
| Perception | The ability of a plant cell or tissue to detect a hormone that depends on a cell’s physiology at the time the hormone is present. |
| Perennial | A plant that lives for more than two growing seasons (more than two years); perennials may be woody or herbaceous (the latter with underground perenniating structures). |
| Plant hormone | A signal molecule that regulates growth, development, and responses to environmental and other signals, also known as a plant growth regulator or phytohormone. |
| Rachis | The stalk of a flower that is situated between the peduncle and the pedicel on a compound leaf. Also the name for the central axis on a compound leaf where the leaflets are attached. |
| Reproductive meristem | The apical meristem that transforms into the reproductive tissues (the inflorescence) of the plant. |
| Response | The action taken by the plant after perception of a signal. |
| Senescence | A regulated process that results in cell death and is associated with leaf fall and death of the plant. |
| Signal transduction | The process in which the perception of a signal, such as a hormone, is moved within a cell, cell to cell, or throughout a tissue. |
| Simple inflorescence | A type of inflorescence with a peduncle, rachis, pedicel, and single flower structure. |
| Synthetic hormone | A hormone made by people; can mimic the response of a naturally occurring hormone. |
| Tropism | A growth or turning response to an environmental or other signal such as phototropism (response to light) or gravitropism (response to gravity); can be controlled by auxin and other hormones. |
| Umbel | An inflorescence with multiple flowers originating from a common point. |
| Woody perennial | A plant that lives for more than a year, has hard rather than fleshy stems, and bears buds that survive above ground in winter. Trees, shrubs, many vines, and bamboo are examples of woody perennials. |
