Structure and Function

1. Structure and Function In Different Environments

2. Introduction • Plants have various structures that help them to survive in different environments. • In this presentation, we will look at the adaptations in the structures of plants, including roots, stems,and leaves of plants in different environments. • We will compare the structure and function of plant parts from the following environments: desert, wetlands, forest, and tundra.

3. Desert- A Definition • A desert is a region that receives an extremely low amount of precipitation (rain or snow), less than enough to support growth of most plants. • Plants lose a lot of moisture through a process called transpiration. (Sort of like a person losing water through perspiration.) • Deserts can be hot or cold.

4. Wetlands- A Definition • A wetland is an area between a land-based and a water-based ecosystem. • Wetlands include bogs, fens, marshes, and swamps. • Although there are many different types of wetlands, they have three physical characteristics in common.

5. Wetlands- A Definition • Water– Wetlands are covered with shallow water for at least some time during the year. • Soil– The soil often has little or no oxygen. • Plants– Wetlands provide habitat for “water-loving” aquaticplants (hydrophytes). These plants are adapted to living in saturated (really full of water) soil all or part of the year.

6. Tundra- A Definition • The word "tundra" usually refers only to the areas where the subsoil is frozen all the time (permafrost). • The plants in this environment include shrubs, sedges, grasses, mosses, and lichens.

7. Forest- A Definition • A forest, or woods, has many trees. • There will usually be an upper tree layer (canopy) and the understory. • Other plants, such as shrubs, vines, flowers, and mosses, are found in forests. • Forests can include rainforests, boreal forests, and conifer forests.

8. Roots • The four major functions of roots are: • Absorption of water and nutrients (food) • Anchoring the plant to the ground • Storage of food and nutrients • To prevent soil erosion • Buttress roots are large roots on all sides of a tree with a wide base or a tree with shallow roots.

9. Roots: Dry Environment • Some desert plants have long taproots that go all the way to the water table, if present. • Some desert plants have adapted to the weather by having wide-spreading roots,to absorb water from a greater area of the ground.

10. Roots: Wetland Environment • Emergent – Rooted in soil, but plant parts extend above the waterSubmergent – The entire plant lives underwater.

11. Roots: Wetland Environment • Floating – Leaves float on the surface, while roots hang down into the water or are planted in the soil • Riparian – Found along the edges of wetlands or other water bodies

12. Roots: Tundra Environment • There are no deep root systems in the plants (vegetation) of the arctic tundra. • Many plants have rootlets (rhizoids) instead of roots.

13. Stems • A stem is the part of the plant that usually grows above the ground and holds the leaves. • The stem has four main functions: • Supports and elevates the plant, leaves, flowers, and fruits • Transports fluids between the roots and the shoots • Stores nutrients • Produces new living tissue

14. Stems • Some plants have thorns on their stems for protection. • Some plants have stems that wrap around other plants or structures. This provides a way to support the plant as it grows.

15. Stems • The stems of many desert plants feel “waxy”. Some desert plants store water in their leaves, roots, and stems. • The stems of tundra plants are often very short. Plants grow close to the ground in this environment. Tundra plants do not have woody stems.

16. Stems • The stems of many aquatic plants are flexible. • Flexible stems move easily in water currents.

17. Leaves • The shape and structure of leaves varies considerably from plant to plant. • The main purpose of leaves is to produce food (energy). • Another purpose of a leaf is to get carbon dioxide from the air (atmosphere) to make sugar and release oxygen.

18. Leaves: Dry Environment (desert) • Desert plants often have small, spiny leaves. • They are designed to reduce water loss in the plant.

19. Leaves: Temperate Environment(forest) • Some trees have broad leaves that absorb water and sunlight. • Some trees have “needles” for leaves. The needles’ shape and waxy coating help the plant conserve water during the cold winter and in hot climates.

20. Leaves: Tundra Environment • Tundra plants have very tiny leaves. • There are usually many leaves on one stem. • Sometimes the leaves appear to be “wooly”.

21. Leaves: Wetland Environment • Leaves are usually round and flat or long and thin. • The flat leaves float on the surface. • The thin leaves move easily when water flows.

22. Special Structures… • Carnivorous plants have adapted to living in the low-nutrient areas of wetlands (bogs and fens) in a special way. • They have structures that allow the plant to trap and digest insects. The insects provide the necessary nutrients that they cannot obtain from the soil.