25.3 Plant Adaptations

1. 25.3Plant Adaptations Essential Question How are plants adapted to different environments?

2. Aquatic Plants • Aquatic plants live in an muddy water environment that has very little oxygen • Adaptations: • Many plants have tissues with large air-filled spaces through which oxygen can diffuse • The reproductive adaptations include seeds that float in the water and delay germination for long periods • Many grow quickly after germination and extend the growing shoot above the water’s surface

3. Water lilies have long petioles that extend down into the root system; oxygen diffuses from these open spaces into the roots.

4. Salt-Tolerant Plants • Plants that live in salty water must be able to get rid of excess salt. • Their leaves have specialized cells that pump salts out of the plant tissues and onto the surface of the leaf where it is washed off by the rain.

5. Mangroves have air roots with air spaces that conduct air down to the roots

6. Desert Plants • Plants that live in the desert biome are called xerophytes. • They must be able to tolerate extreme conditions such as strong winds, daytime heat, sandy soil, and infrequent rain. • Desert plants have extensive root systems, reduced leaves, and thick stems that can store water.

7. Seeds of desert plants can remain dormant for many years and germinate only when sufficient moisture guarantees them a chance for survival. • Other plants have bulbs, tubers, or specialized stems that can remain dormant for years. • These plants can mature, flower, and set seeds in a matter of weeks or even days when water is present.

9. Cactuses have spiny leaves and have thick green stems that carry out photosynthesis and are adapted to store water.

10. Other ways of Obtaining Nutrients • Some plants live in bogs, wet, acidic environments where there is very little or no nitrogen. • Bacteria that normally cause decay and return nitrogen to the soil can not live in acidic environments • These plants have adaptations to obtain nutrients. • Some plants have specialized features for obtaining nutrients other than photosynthesis

11. Venus’ flytrap has leaf blades that are hinged in the middle so if an insect touches the trigger, it closes up and traps it inside Venus Fly Trap

12. Pitcher plants drown and their prey in pitcher-shaped leaves that trap and digest insects.

13. Sundews trap insects on leaf hairs tipped with sticky secretions

14. Parasitic Plants • Parasitic Plants harm their host and can pose a serious threat to its survival by extracting nutrients from the plant. • Examples are mistletoe and Cuscuta.

15. Cuscuta Mistletoe

16. Epiphytes • Epiphytes are plants that are not rooted in soil but instead grow directly on the bodies of other plants. • They are not parasites because they do not absorb nutrients from the plant. • They gather only moisture from rainfall • Most are found in tropical rain forests and other moist biomes. • Examples: Spanish moss, bromeliads, and orchids

17. Bromeliad

18. Chemical Defenses • Plants must be able to defend themselves from insects if they are to survive. • Many plants do this my manufacturing compounds, such as poisons, that have powerful effects on animals. • Some are lethal • Some disrupt normal growth and development • Humans have commercial uses for these compounds that include aspirin, codeine, and nicotine.

19. Foxglove