Plant Responses

4. Plant hormones that regulate plant growth. Hormones are signal molecules produced within the plant, and occur in extremely low concentrations.
5. the orientation of a plant in response to light, either towards the source of light (positive) or away from it (negative).
6. The ability of an organism to respond to seasonal changes in day length
8. The region of plant tissue found at the growing tips of roots and shoots. Consists of actively dividing cells which form new tissue.
9. The growth movement of a plant in response to an environmental stimulus.
10. A plant that flowers only after being exposed to a night length that is longer than its critical night length (short day, long night).
12. The protective sheath that is found around the emerging shoot (plumule).
13. Growth response of a plant to gravity.
16. The natural loss of parts of a plant, typically dead leaves and ripe fruit.
17. A pigment that absorbs red and far-red light. Their function is to regulate flowering in plants. Pr and Pfr.
18. A plant that requires a night length shorter than its critical night length to flower (long day, short night).
19. Also known as IAA
20. Another name for Shoot.

1. A phytohormone that stimulates cytokinesis (cell division).
2. A period of suspended growth in order to lower energy requirements when resources are scarce.
3. When an animal eats a plant or a plant-like organism
7. Another name for Root
11. The reversible movement of a plant in response to the onset of darkness.
14. Growth hormone which plays an essential role in the growth processes and tropisms in roots and stems. Controls the elongation of cells.
15. Rapid, reversible turgor movements in response to a change in stimulus intensity