FRUITS AND SEEDS

1. FRUITS AND SEEDS

2. Fruits • Part of sexual reproduction unique to angiosperms • Develops from fertilized ovary • Protect the enclosed seeds and aids in seed dispersal • Widely utilized as a significant food source

3. Fruit wall or Pericarp • Develops from the ovary wall • Composed of three layers • outer exocarp • middle mesocarp • inner endocarp • Appearance of these three layers varies among different fruit types

4. Fruit Types I: Simple Fruits • Derived from the ovary of a single carpel or several fused carpels • Can be fleshy or dry

5. Type I.a: Simple fleshy fruit • Derived from the ovary of a single carpel or several fused carpels • Often soft and juicy • Seed dispersal occurs when an animal eats the fruit • Types of simple fleshy fruits • BERRY -HESPERIDIUM -PEPO • DRUPE -POME

6. Berry • Thin exocarp • Soft fleshy mesocarp • Endocarp with one to many seeds • Tomatoes, grapes and dates

7. Hesperidium • Berry with a tough leathery rind • Oranges, lemons, and other citrus fruitS

8. Pepo • Tough outer rind that has both receptacle tissue and exocarp • Mesocarp and endocarp are fleshy • All members of the squash family (pumpkins, melons, and cucumbers)

9. Drupe • Thin exocarp • Fleshy mesocarp • Hard stony endocarp which encases the seed • Cherries, peaches, and plums Exocarp Mesocarp Endocarp

10. Pome • Fleshy part develops from the enlarged base of the perianth (calyx and corolla) that is fused to the ovary wall • Apples and pears

11. Accessory fruits • Contain flower parts other than the ovary • Both the pepo and pome are example

12. Type I.b: Simple dry fruits • Derived from the ovary of a single carpel or several fused carpels • Pericarp may be tough and woody or thin and papery • Two types: • dehiscent • indehiscent

13. Dry dehiscent fruits • Split open at maturity to release seeds • Wind often aids seed dispersal • Types characterized by how they open: • Follicle - splits open along one seam (magnolia and milkweed) • Legume - splits open along two seams (beans and peas) • Capsule - several pores or slits (cotton and poppy)

14. Legume - pea • Legume pod splits along two seams to disperse seeds

16. Capsule • Cotton fruit is a capsule splitting open along five lines • Seeds are covered with long hairs (trichomes) which are the commercial cotton fiber

17. Indehiscent fruits • Do not split open to release seeds • Common types • Achene • Samara • Grain • Nut

18. ACHENES One-seeded fruit Pericarp free from the seed Sunflower “seeds” SAMARAS Winged achenes Dispersed by wind Fruit in maple trees and ash trees

19. Grains • Also called caryopsis • Single seeded fruits • Pericarp fused to seed coat • Fruits of all cereal grasses: wheat, rice, corn and barley

20. Wheat grain Fused seed coat and ovary wall layers

21. Nuts • One-seeded fruits • Hard stony pericarps • Hazelnuts, chestnuts, and acorns • Other things commonly called nuts that are not true nuts but are actually seeds

22. Fruit Types II: Aggregate fruits • Develop from a single flower with many separate carpels • Raspberries and blackberries • Strawberries also contain accessory tissue • Seeds on the surface are actually separate achenes inserted on the enlarged, fleshy, red receptacle

23. Raspberries and Blackberries

24. Aggregate-Accessory Fruit • Strawberries also contain accessory tissue • Seeds on the surface are actually separate achenes on enlarged, fleshy receptacle

25. Fruit Types III: Multiple fruits • Result from the fusion of ovaries from many separate flowers on an inflorescence • Figs and pineapples are examples of multiple fruits one of many ovaries that are fused together

26. Seed Structure and Germination

27. Seeds • Develop from the fertilized ovules • Include an embryonic plant and some form of nutritive tissue within a seed coat • Because of the stored nutrients many seeds are valuable foods

28. Dicots and monocots • Refers to the number of seed leaves or cotyledons present in the seed • Dicot seeds have two cotyledons • Monocots have one cotyledons

29. Dicot seed • Cotyledons attached to and enclose the embryonic plant • Cotyledons occupy the greatest part of the seed • Cotyledons have absorbed the nutrients from the endosperm which may be entirely used up

30. Dicot seed - Lima bean • Thin seed coat • Hilum and micropyle visible on surface • Hilum - attachment • Micropyle - opening in the integuments • If the seed coat is removed the two large food-storing cotyledons are visible

31. Dicot embryo • Consists of : • Epicotyl - part that develops into the shoot; typically has embryonic leaves - also called a plumule • Hypocotyl - portion of embryo between cotyledon attachment and radicle (between stem and root) • Radicle - the embryonic root

32. Monocot seed • Cotyledon transfers food from the endosperm to the embryo • In several monocot families large amounts of endosperm are present

33. Monocot seeds - Corn kernel • Reminder: a grain is a one-seeded fruit in which the seed coat is fused to the pericarp • Extensive endosperm occupies much of the seed • Small embryo with a single cotyledon • Presence of a coleoptile and the coleorhiza

34. Seed germination • Absorption of water • Emergence of the radicle • Shoot emerges: • In dicots the hypocotyl elongates and breaks through the soil • In monocots the coleoptile emerges protecting the epicotyl tip • Soon after the tissues are exposed to sunlight, they develop chlorophyll and begin to photosynthesize

37. Tomatoes • Native to Andes Mts in South America • First cultivated in Mexico • Spanish Conquistadors introduced tomatoes to Europe in the 16th century

38. What is in a name? • Name among native peoples in Mexico was tomatl • In Europe there were lots of names for this fruit - love apple or pomme d’amour was the French name • Scientific name Lycopersicum esculentum (meaning edible wolf peach)

39. Poisonous Relatives • Member of the family Solanaceae (called the potato or tomato family) • Family known for its poisonous plants • Also called the nightshade family because of deadly nightshade and henbane • Also called tobacco family

40. Suspect Plant • Because of the poisonous relatives, tomatoes were suspected by many as poisonous • Hard reputation to live down • In 1820 Col. Robert Johnson ate a bushel of tomatoes in front of a crowd to prove they were safe

41. Popular “vegetable” • Although botanically it is simple fleshy fruit (a berry), in 1893 the Supreme Court ruled it was a vegetable • Widely used in fresh, canned, dried, pickled, and processed varieties • Also a favorite experimental tool - used in space shuttle, genetic engineering, and cloning experiments

42. Apples - Malus pumila • Family Rosaceae • Long history of use • One of the first trees cultivated • Native to Caucasus Mts of western Asia • Many legends associated with apples

44. Apple Varieties • Pome - simple accessory fruit • Hundreds of varieties exist but only a few dominate the market • Delicious, Rome, Gala, McIntosh • Most apple trees are produced by grafting rather than by seeds • Grafting creates thousands of identical copies with the desired traits

46. Citrus Fruits

47. Citrus Fruits - Oranges • Members of the family Rutaceae • Fruit is a hesperidium • Rind impregnated with oil glands (oils important for perfumes and cosmetics) • Individual carpels filled with one-celled juice sacs • Fruits high in Vitamin C

48. Citrus Fruits • Most citrus are native to southeast Asia • Citrons first citrus fruit introduced to Mediterranean countries during Greek and Roman times • Sweet oranges not introduced till 16th century

49. Introduction to New World • Spanish and Portuguese explorers introduced citrus to New World • Sour oranges grown in Florida by 1565 • Sweet oranges introduced after 1821 - grafted onto sour orange rootstock • Florida remains leading orange-producing state for juices • Grapefruit developed in Caribbean (pummelo x orange)

50. Pummelos