Term
|
Definition
Certain plants respond to touch or pressure.
Vines with tendrils sense pressure and grow toward the pressure, wrapping the tendrils afound supports. |
|
|
Term
|
Definition
| A plant responds to light, growing towards the light because cells on one side of the shoot grow longer than cells on the other side of the shoot. |
|
|
Term
|
Definition
| When a plan is placed on its side or turned upside down, the roots and shoots change their direction of growth. Most shoot tips have negative gravitropism; they grow upward, away from the center of the earth while others have positive gravitropism as they grown downward, toward the center of the earth. |
|
|
Term
|
Definition
Night length is an external stimulus for many plants that begin reproducing or flower only in certain seasons.
Examples are poinsettias and ragweed. |
|
|
Term
|
Definition
Long day plants flower in spring or early summer when night length is short.
Examples are clover, spinach, and lettuce. |
|
|
Term
Seasonal changes in leaves
Loss of leaves
leaf color change |
|
Definition
Some trees lose their leaves at the same time each year so that bare branches reduce the amount of water loss and can help plants survive low temperatures or long periods without rain.
Chlorophyll [green pigment) breaks down so that yellow, red, and orange pigments can be seen without the domination of green. |
|
|
