Basic Plant Structure

1. Basic Plant Structure Roots Stems Leaves

3. General Organization • A plant has two organ systems: • the shoot system • Found above ground and includes the organs such as leaves, buds, stems, flowers (if the plant has any), and fruits (if the plant has any). • the root system • Found below ground and includes roots, tubers, and rhizomes

4. Classifying Plants • Nonvascular plants: • have no vessels • no stems • No leaves • No roots • Examples: Mosses & Liverworts

5. Classifying Plants VascularPlants: • have vessels to transport food and water • Xylem: transports water • Phloem: transports food & nutrients • have roots, stems and leaves • Example: Grass, corn, trees, flowers, bushes

6. Gymnosperm • Flowerless plants • "naked seeds" • cone bearing plants (seeds grow on cones) • needle like leaves • usually stay green year round • Examples: pine trees & evergreens

7. Angiosperm • flowering plants • seeds are enclosed in a fruit • have finite growing seasons • Examples: grasses, tulips, oaks, dandelions • Divided into two main groups: Monocots & Dicots

8. Monocot Seed • Angiosperms that have 1 seed leaf (cotyledon) • parallel veins on leaves • 3 part symmetry for flowers • fibrous roots • Example: lilies, onions, corn, grasses, wheat

10. Dicot Seed • Angiosperms that have 2 seed leaves (cotyledons) • net veins on leaves • flowers have 4-5 parts • have a taproot • Examples: trees and ornamental flowers

13. Roots • Roots absorb NUTRIENTS and water • anchor the plant in the soil • provide support for the stem • store food • usually below ground • There are two major types of root systems in plants.. • Taproot and fibrous root.

15. Root Types • Taproot systems have a stout main root with a • limited number of side-branching roots. • Examples of taproot system plants: • nut trees, carrots, radishes & dandelions. • Fibrous root systems have many branched roots. • Examples of fibrous root plants: • most grasses, marigolds and beans

16. Stems • The stem is the main trunk of a plant. • provide structure and support for leaves, flowers and fruits • may also store food • carry nutrients and water • Most stems grow above ground BUT… • many stems grow below ground or are ground hugging • Some modifications include: • bulbs, rhizomes, runners, tubers

17. Leaves • are lateral outgrowths from the stem • main function is food production through photosynthesis • most commonly flat, broad and green. • maximizes their function of absorbing sunlight and transforming it into food.

19. Leaves

20. Function of leaves • Trap light energy for photosynthesis Producing sugar from photosynthesis • Exchange of gases – oxygen and carbon dioxide

22. Structure Wide Helps to catch more light energy Thin Help get carbon dioxide from bottom to top of leaf for photosynthesis

23. Leaf structure Greener on top CO2 gets in here

24. Leaf diagram – palisade layer Most chlorophyll CO2

25. Leaf cell - palisade Position? Upper surface of leaf Features? Box shape Chloroplasts Function? Photosynthesis

26. Gas exchange • Leaves are designed to allow carbon dioxide to get to the main chlorophyll layer at the top of the leaf • They have small holes called stomata on the under surface • Each hole is open & closed by 2 guard cells

27. Leaf diagram – stoma and guard cells

28. Stoma position

29. Stoma is a small hole Its size is controlled by 2 guard cells closed open

30. Stoma function is for gas exchange in the leaf oxygen Guard cell Provided plant is photosynthesising Carbon dioxide

31. Stomata open and close at different times of the day When it is light the plant needs CO2 for photosynthesis so the stoma open At night (darkness) they close

32. Gas exchange

33. Buds • Buds are undeveloped shoots and flowers • classified terminal or lateral. • Terminal buds can be identified by their location • at the tip of a stem. • Lateral buds are located at the sides of the stem. • Cabbage and head lettuce are examples of very large • terminal buds • Brussels sprouts are edible lateral buds. • Broccoli is an example of edible flower buds.

34. Flowers • Reproductive organ of the plant – produce seeds • Flowers are usually both male and female • The male part of the flower is the STAMEN • The female part of the flower is the PISTIL • See your sheet for more detail on flower anatomy

35. Flowers Continued • Other external parts of flowers include: • SEPALS - usually green and enclose other • parts of the flower in the bud. • PETALS are usually brightly colored and may • contain aromatic substances as well as nectar glands.

36. MALE - STAMENS • Stamens produce pollen which contain the sperm • Stamens are made of a head called the anther and a stock called the filament.

37. FEMALE – PISTIL • Pistil holds the egg cells. • The pistil is made of a sticky head called the stigma, a stock called the style, and the ovary that holds the egg cells.

39. Petal Pistil Corolla Stamen Calyx Sepal Pollen Stigma Anther Style Filament Ovary

40. More on classification of fruits! Fruit • A ripened ovary or group of ovaries containing the seeds • the ovary enlarges forming the mature fruit. • A simple fruit forms from the ripening of the ovary of a single pistil. • Eg. Tomatoes & oranges

41. More on Fruit • A complex fruit is derived from more than one ovary resulting in a clustering of smaller fruit elements • Eg. Raspberries, strawberries – not really berries!

42. The parts of the flower and what part they become in the fruit.

43. Fruit or Vegetable?? • Botanically: • fruit always develops from a flower and is • composed of at least one ripened ovary. • a vegetable is any edible part of a plant other than the flower. • Most people think: • a fruit is an edible plant part that is sweet and eaten as a dessert. • vegetable is a plant part that is edible, but not particularly sweet.

44. Which is it? Many fruits, such as tomatoes, squash, cucumbers, corn and eggplant, are popularly called vegetables. However, only one vegetable, rhubarb (the edible petiole), is used as a fruit.