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8.5 Science Vocab
Term | Definition |
---|---|
tropism | a plant's growth response toward or away from a stimulus. |
hormone | chemical that affects how the plant grows and develops. |
auxin | one important plant hormone that speeds up the rate at which a plant's cells grow. |
photoperiodism | a plant's response to seasonal changes in length of day and night. |
short-day plants | flower when nights are longer. |
long-day plants | flower when nights are shorter. |
critical night length | the number of hours of darkness that determines whether or not a plant will flower. |
day-neutral plant | flowering cycle is not sensitive to periods of light and dark; ex.- dandelions, rice, tomatoes. |
dormancy | period when an organism's growth or activity stops. |
annuals | flowering plants that complete a life cycle within one growing season. |
biennials | angiosperms that complete their life cycle in two years. |
perennials | flowering plants that live for more than two years. |