Chapter 23 Reproduction in Plants

1. Chapter 23 Reproduction in Plants Section 1: Introduction to Plant Reproduction Section2: Flowers Section 3: Flowering Plants

2. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Vegetative Reproduction • The plants that result from vegetative reproduction are clones of the original plant because their genetic makeups are identical to the original plant. Strawberry plant

3. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Advantages of Vegetative Reproduction • It is faster to grow new plants than from a spore or a seed. • The resultant plants are more uniform in their characteristics. • The only way to produce some fruits that do not produce seeds

4. Reproduction in Plants • When conditions improve, some of these pieces are able to resume growth in a new location. Chapter 23 23.1 Introduction to Plant Reproduction Natural Vegetative Reproduction • When conditions are dry, some mosses dry out, break apart, and are scattered by the wind. Moss

5. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Humans Use Vegetative Reproduction • Farmers, horticulturists, and scientists can use buds, leaves, stems, or root pieces from certain plants to grow new plants. • A few cells of plant tissue can be placed on nutrient agar in sterile conditions to produce hundreds of identical plants.

6. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Alternation of Generations • The life cycle of most plants includes a diploid (2n) sporophyte stage and a haploid (n) gametophyte stage.

7. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction • The gametophyte stage produces gametes—egg and sperm. • In nonvascular plants, the sperm must have a small amount of water to get to the egg.

8. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction • In vascular plants, the sperm may be carried by the wind, or another vector such as an insect. • Fertilization of the egg by the sperm forms a cell that is the first cell of the sporophyte stage.

9. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Moss Reproduction and Life Cycle • The life cycle of the mosses begins with the dominant stage, the gametophyte.

10. Reproduction in Plants • Sperm are produced in the male structure, called the antheridium. Chapter 23 23.1 Introduction to Plant Reproduction • There are both male and female forms of the gametophyte. • Eggs are produced in the female structure, called the archegonium.

11. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction • Sperm require water to swim to the egg. • The chemical that allows sperm to find the egg is chemotaxis.

12. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction • The mature sporophyte consists of a stalk that grows in the gametophyte stage.

13. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction • At the tip of the stalk is a capsule where up to 50 million spores may form by meiosis. • The spores produce a protonema that can develop into the gametophyte plant and start a new cycle.

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15. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Fern Reproduction and Life Cycle • Another life cycle that has alternation of generations and produces spores is that of the fern.

16. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction • Spores are produced from the sori, on the underside of a frond. • If a fern spore lands on damp, rich soil, it can grow and form a tiny, heart-shaped gametophyte called a prothallus.

17. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction • Fertilization produces a sporophyte that grows from the prothallus. • The young sporophyte develops into a frond to start the cycle over again.

18. Conifers are heterosporus—they produce two types of spores that develop into male and female groups. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Conifer Reproduction and Life Cycle

19. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Female Cones • At the base of each scale on a female cone are two ovules. • Each ovule has a megasporangium that produces megaspores. • One of the megaspores develops into the female gametophyte.

20. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Male Cones • Each scale on the male cone contains hundreds of sporangia. • The sporangia produce microspores, which produce the male gametophyte, or pollen grain.

21. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Pollination • Pollination occurs when the pollen grain from one species of a plant lands on the female reproductive structure of a plant of the same species. • The pollen grain is trapped in a sticky substance called the pollen drop which is located near the micropyle.

22. Reproduction in Plants Chapter 23 23.1 Introduction to Plant Reproduction Seed Development • Seed development within the cone may take as long as three years. • The seed embryo will use the cotyledons for photosynthesis upon sprouting. Conifer’s Life Cycle

23. Reproduction in Plants Chapter 23 23.2 Flowers Flower Organs • Flowers are the reproductive structures of anthophytes.

24. Reproduction in Plants Chapter 23 23.2 Flowers • Flowers have several organs that provide protection or support, or are involved in the reproductive process. • There are basically four structures—sepals, petals, stamen, and pistils.

25. Reproduction in Plants Chapter 23 23.2 Flowers • Sepals may be green and look like leaves and petals. • Petals attract animal pollinators and provide a landing pad. • Sepals and petals open and close to protect the reproductive parts of the flower.

26. Reproduction in Plants Chapter 23 23.2 Flowers • Most flowers have several stamen—the male reproductive organ—surrounding the central part of the flower. • The filament stalk supports the anther, which contains the pollen grains.

27. Reproduction in Plants Chapter 23 23.2 Flowers Flower Adaptations • Structural differences • Flowers that have sepals, petals, stamens, and one or more pistils are called complete flowers. • If a flower is missing one or more of these organs, it is an incomplete flower.

28. Reproduction in Plants Chapter 23 23.2 Flowers • Flowers that have both stamens and pistils are called perfect flowers. • An imperfect flower has either functional stamens or pistils.

29. Reproduction in Plants Chapter 23 23.2 Flowers • The number of flower organs distinguishes dicots and eudicots from monocots. • Monocots generally have multiples of three. • When the petal number is a multiple of four or five, the plant is either a dicot or a eudicot. • The number of other organs often is the same multiple of three, four, or five.

30. Reproduction in Plants Chapter 23 23.2 Flowers Pollination Mechanisms • Flower adaptations that relate to pollination include flower size, shape, color, and petal arrangements. • Animal pollination • Wind pollination • Self pollination

31. Reproduction in Plants Chapter 23 23.2 Flowers Photoperiodism • The flowering response to the number of hours of uninterrupted darkness is known as photoperiodism. • Flowering plants are divided into four different groups based on the critical period.

32. Reproduction in Plants Chapter 23 23.2 Flowers Short-day Photoperiodism • A short-day plant flowers when exposed daily to a number of hours of darkness that is greater than its critical period.

33. Reproduction in Plants Chapter 23 23.2 Flowers Long-day Photoperiodism • A long-day plant flowers when the number of hours of darkness is less than its critical period.

34. Reproduction in Plants Chapter 23 23.2 Flowers Intermediate-day Photoperiodism • An intermediate-day plant flowers as long as the number of hours of darkness is neither too great or too few.

35. Reproduction in Plants Chapter 23 23.2 Flowers Day-neutral Photoperiodism • A day-neutral plant flowers over a range in the number of hours of darkness.

36. Reproduction in Plants Chapter 23 23.3 Flowering Plants Life Cycle • The life cycle of a flowering plant includes gametophyte and sporophyte generations.

37. Reproduction in Plants Chapter 23 23.3 Flowering Plants Results of Reproduction • Fertilization is only the beginning of a long process that ends with the formation of a seed.

38. Reproduction in Plants Chapter 23 23.3 Flowering Plants Seed and Fruit Development • The sporophyte begins as a zygote, or a 2n cell. • The zygote undergoes numerous cell divisions to form an embryo. • Nourishment for the embryo comes from a tissue called the endosperm. Double Fertilization in Flowering Plants

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40. Reproduction in Plants Chapter 23 23.3 Flowering Plants • As the endospore matures, the outside layers of the ovule harden and form a protective tissue called the seed coat. • As the ovule develops into a seed, changes occur in the ovary that lead to the formation of fruit.

41. Reproduction in Plants Chapter 23 23.3 Flowering Plants Seed Germination • When the embryo in a seed starts to grow, the process is called germination. • The first part of the embryo to appear outside the seed is the radicle.

42. Reproduction in Plants Chapter 23 23.3 Flowering Plants • The hypocotyl is the first part of the seed to appear above ground. • The cotyledons will provide nourishment for the seedling until photosynthesis begins.

43. Reproduction in Plants Chapter 23 Chapter Resource Menu Chapter Diagnostic Questions Formative Test Questions Chapter Assessment Questions Standardized Test Practice biologygmh.com Glencoe Biology Transparencies Image Bank Vocabulary Animation Click on a hyperlink to view the corresponding feature.

44. A B C D Reproduction in Plants Chapter 23 CDQ 1 Chapter Diagnostic Questions What term is used to describe the process in which new plants grow from parts of an existing plant? budding regeneration vegetative reproduction sexual reproduction

45. A B C D Reproduction in Plants Chapter 23 CDQ 2 Chapter Diagnostic Questions What is the threadlike structure of a spore which develops into a gametophyte? chemotaxis prothallus protonema microspore

46. A B C D Reproduction in Plants Chapter 23 CDQ 3 Chapter Diagnostic Questions What structure of the plant embryo first appears outside the seed? cotyledon first leaf hypocotyls radicle

47. A B C D Reproduction in Plants Chapter 23 FQ 1 23.1 Formative Questions Which scientist uses plant cells to grow new plant tissues on nutrient agar? botanical technologist horticulture specialist plant physiologist tissue-culture technician

48. A B C D Reproduction in Plants Chapter 23 FQ 2 23.1 Formative Questions What is the term for the movement of cells in response to a chemical? chemitropism chemotaxis chemiosmosis hydrochemisis

49. A B C D Reproduction in Plants Chapter 23 FQ 3 23.1 Formative Questions What is the tiny heart-shaped gametophyte produced from a fern spore called? frond sorus prothallus protonema

50. A B C D Reproduction in Plants Chapter 23 FQ 4 23.1 Formative Questions What is the term for a plant that produces two types of spores that develop into male or female gametophytes? bisporous diasporous gametosporous heterosporous