2. Asexual Reproduction in Plants Produces offspring genetically identical to parent Also known as vegetative reproduction

3. Methods A. Runners: horizontal, above-ground stems example: Bermuda grass

4. B. Bulbs: short, underground stem examples: onion, daffodil, tulip

5. C. Rhizomes: horizontal, underground stems examples: ferns

6. D. Tubers: swollen, fleshy underground stems example: potato

7. Germination Water and oxygen are needed for a seed to sprout. Germination: process in which a plant embryo resumes its growth. The first sign of germination is the emergence of the root, also known as radicle.

9. Plant Life Spans 1.Perennials: live for several years May reproduce often during their life May be deciduous or evergreen Stems woody or herbaceous Examples: trees, shrubs, daffodils, vines

11. 2.Annuals: complete their life cycle in one growing season. Almost all are herbaceous. Examples include sunflowers, beans, corn, many weeds.

12. 3.Biennials: take two growing seasons to complete their life cycle. Produce flowers during the 2 nd season Examples include carrots and onions

13. Plant Growth and Development I. Nutrients 1. Carbon dioxide and water for photosynthesis 2. Oxygen for cellular respiration 3. Minerals needed for growth Nitrogen, phosphorus, potassium,

14. II. Hormones Auxin is a growth-promoting chemical that causes stems to bend. Auxin is a growth-promoting chemical that causes stems to bend. Experiment on page 598 Experiment on page 598 Auxin accumulates on the dark side of a plant and causes the cells to elongate. Auxin accumulates on the dark side of a plant and causes the cells to elongate. Another hormone is ethylene, which is a gas. Another hormone is ethylene, which is a gas. Ethylene stimulates fruit ripening. Ethylene stimulates fruit ripening.

15. Environmental Influences I.Tropisms: responses in which plants grow either toward or away from a stimulus A. The bending of a plant toward the light is a positive phototropism. B. The downward growth of roots is a positive gravitropism. C. The upward growth of shoots is a negative gravitropism.

16. D.Thigmotropism is a response to touch. Coiling of a vine around a trellis is a positive thigmotropism.

17. II.Nastic movements are rapid, reversible responses to non-directional stimuli. Examples include opening and closing of flowers and closing of a Venus fly trap

18. III. Photoperiodism The response of a plant to the length of days and nights. Long-day plants produce flowers when days are longer than a certain number of hours. Examples: Irises

19. Short-day plants produce flowers when days are shorter than a certain number of hours. Examples: Poinsettias

20. Day-neutral plants do not require specific day lengths to flower. Examples include roses, potatoes