| A | B |
|---|
| alternation of generations | plant life cycle in which the plant alternates between haploid and diploid phases |
| sporophyte | diploid, spore-producing phase of a plant life cycle |
| gametophyte | haploid, gamete-producing phase in a plant life cycle |
| sepal | modified leaf that covers and protects the flower while it develops |
| petal | modified leaf that surrounds a flower's reproductive structures |
| stamen | male structure of flowering plants; includes the filament and anther, which produces pollen |
| carpel | female structure of flowering plants; made of the ovary, style, and stigma |
| ovary | organ in which female gametes develop prior to fertilization |
| endosperm | tissue within seeds of flowering plants that nourishes an embryo |
| double fertlization | process by which two sperm of a flowering plant join with an egg and a polar body, forming an embryo and endosperm |
| dormancy | state of inactivity during which an organism or embryo is not growing |
| germination | process by which seeds or spores sprout and begin to grow |
| regeneration | process by which a new plant can grow from a fragment of a nonreproductive structure, such as a root, stem, or leaf |
| vegetative reproduction | asexual reproduction in which a stem, leaf, or root will produce a new individual when detached from a parent plant |
| hormone | chemical signal that is produced in one part of an organism and affects cell activity in another part |
| gibberellin | plant hormone that stimulates cell growth |
| ethylene | plant hormone that is produced in fruits and causes them to ripen |
| cytokinin | plant hormone that stimulates the final stage of cell division, cytokinesis; also involved in the growth of side branches |
| auxin | plant hormone that stimulates the lengthening of cells in the growing tip |
| tropism | movement or growth of a plant in response to an environmental stimulus |
| phototropism | growth of a plant toward a light source |
| thigmotropism | turning or bending of a plant in response to contact with an object |
| gravitropism | growth of plants in response to gravity; plant stems grow upward, against gravity, and roots grow toward the gravitational pull |
| photoperiodism | response of an organism to changes in the length of the day |
