1. Biology, 9th ed, Sylvia Mader
Chapter 28
Chapter 28
Reproduction in Plants
Reproduction in Plants

2. Biology, 9th ed, Sylvia Mader
Outline
Chapter 28
Reproduction in Plants
Reproductive Strategies
Alternation of generations
Adaptation to a land environment
Flowers
Pollination
Fertilization
Seed Development
Fruit
Seed Germination
Asexual Reproduction
Tissue Culture

3. Reproductive Strategies
Biology, 9th ed, Sylvia Mader
Reproductive Strategies
Chapter 28
Reproduction in Plants
All plants have a two-stage, alternating life cycle
Sporophyte produces haploid spores by meiosis
Spores divide mitotically to become haploid gametophytes
Gametophytes produce gametes
Gametes fuse to produce zygote
Zygote divides mitotically to become diploid sporophyte

4. Alternation of Generations in Flowering Plants
Biology, 9th ed, Sylvia Mader
Alternation of Generations in Flowering Plants
Chapter 28
Reproduction in Plants

5. Reproductive Strategies
Biology, 9th ed, Sylvia Mader
Reproductive Strategies
Chapter 28
Reproduction in Plants
Flower produces two types of spores
Microspore - Male gametophyte
Undergoes mitosis
Becomes pollen grain
Megaspore - Female gametophyte
Becomes embryo sac within an ovary, within an ovule
Ovule becomes seed

6. Biology, 9th ed, Sylvia Mader
Flowers
Chapter 28
Reproduction in Plants
Flower develops in response to environmental signals such as day length
In monocots, flower parts occur in threes and multiples of three
In eudicots, flower parts occur in fours or fives and multiples of four or five

7. Biology, 9th ed, Sylvia Mader
Anatomy of a Flower
Chapter 28
Reproduction in Plants

8. Monocot vs. Eudicot Flowers
Biology, 9th ed, Sylvia Mader
Monocot vs. Eudicot Flowers
Chapter 28
Reproduction in Plants

9. Biology, 9th ed, Sylvia Mader
Flowers
Chapter 28
Reproduction in Plants
Leaf-like sepals protect the bud
Open flower has whorl of petals
Four whorls of modified leaves attached to a receptacle at the end of a flower stalk
Receptacle with a single flower is a peduncle
Receptacle with several flowers is a pedicle

10. Biology, 9th ed, Sylvia Mader
Flowers
Chapter 28
Reproduction in Plants
Leaf-like sepals protect the bud
Open flower has whorl of petals
Four whorls of modified leaves attached to a receptacle at the end of a flower stalk
Receptacle with a single flower is a peduncle
Receptacle with several flowers is a pedicle

11. Biology, 9th ed, Sylvia Mader
Flowers
Chapter 28
Reproduction in Plants
Stamens are male portion of flower
Anther - Saclike container
Filament - Slender stalk
Carpel is female portion of flower
Stigma - Enlarged sticky knob
Style - Slender stalk
Ovary - Enlarged base enclosing ovules

12. Biology, 9th ed, Sylvia Mader
Flowers
Chapter 28
Reproduction in Plants
Complete vs. incomplete flowers:
Complete flowers have sepals, petals, stamens, and a carpel
Incomplete flowers missing one or more of above
Bisexual vs. unisexual flowers:
Bisexual flowers have both stamens and carpel
Unisexual flowers have one but not the other
Monoecious vs. dioecious plants
Monoecious plants have staminate flowers and carpellate flowers on the same plant
Dioecious plants have all staminate or all carpellate flowers

13. Corn Plants are Monoecious
Biology, 9th ed, Sylvia Mader
Corn Plants are Monoecious
Chapter 28
Reproduction in Plants

14. Life Cycle of Flowering Plants
Biology, 9th ed, Sylvia Mader
Life Cycle of Flowering Plants
Chapter 28
Reproduction in Plants

15. From Spores to Fertilization
Biology, 9th ed, Sylvia Mader
From Spores to Fertilization
Chapter 28
Reproduction in Plants
Male Gametophytes
Microspores are produced in anthers
Each anther has four pollen sacs, each with many microsporocytes
Undergoes meiosis to produce microspores
Mitosis produces pollen grains

16. Biology, 9th ed, Sylvia Mader
Pollination
Chapter 28
Reproduction in Plants
Pollination is the transfer of pollen from an anther to the stigma of a carpel
Self-pollination occurs if the pollen is from the same plant
Cross-pollination occurs if the pollen is from a different plant

17. Biology, 9th ed, Sylvia Mader
Chapter 28
Pollination
Reproduction in Plants

18. Production of Female Gametophyte
Biology, 9th ed, Sylvia Mader
Production of Female Gametophyte
Chapter 28
Reproduction in Plants
Ovary contains one or more ovules
Ovule has mass of parenchyma cells
One cell enlarges to become megasporocyte
Undergoes meiois and becomes four haploid megaspores
Functional megaspore divides mitotically until there are eight nuclei of a female gametophyte

19. Biology, 9th ed, Sylvia Mader
Fertilization
Chapter 28
Reproduction in Plants
When pollen grain lands on stigma, it germinates forming a pollen tube
Passes between the stigma and style to reach the micropyle of the ovule
Double fertilization occurs
One sperm nucleus unites with the egg nucleus, producing a zygote
Other sperm nucleus unites with the polar nuclei, forming a 3n endosperm cell

20. Biology, 9th ed, Sylvia Mader
Seed Development
Chapter 28
Reproduction in Plants
Development of eudicot embryo
After double fertilization, endosperm nucleus begins to divide asymmetrically
Small cell is destined to become the embryo
Larger cell divides repeatedly to become a suspensor

21. Development of a Eudicot Embryo
Biology, 9th ed, Sylvia Mader
Development of a Eudicot Embryo
Chapter 28
Reproduction in Plants

22. Biology, 9th ed, Sylvia Mader
Monocot vs. Eudicot
Chapter 28
Reproduction in Plants

23. Development of Eudicot Embryo
Biology, 9th ed, Sylvia Mader
Development of Eudicot Embryo
Chapter 28
Reproduction in Plants
During globular stage, prembryo is ball of cells
Outermost cells will become dermal tissue
Embryo is heart shaped when cotyledons appear
Epicotyl is portion between cotyledons contributing to shoot development
Hypocotyl is portion below that contributes to stem development
Radicle contributes to root development

24. Fruit Types and Seed Dispersal
Biology, 9th ed, Sylvia Mader
Fruit Types and Seed Dispersal
Chapter 28
Reproduction in Plants
Simple Fruits
Simple fruits are derived from single or several united carpels
Legumes are fruits that split along two sides when mature
Dehiscent - Split open
Indehiscent - Fail to split open

25. Biology, 9th ed, Sylvia Mader
Pea Flower and Pea Pod
Chapter 28
Reproduction in Plants

26. Biology, 9th ed, Sylvia Mader
Simple Fruits
Chapter 28
Reproduction in Plants
Fleshy
Drupe
Berry
Pome
Dry
Follicle
Legume
Capsule
Achene
Nut
Grain

27. Biology, 9th ed, Sylvia Mader
Simple Fruits
Chapter 28
Reproduction in Plants
Dispersal
Many seeds are dispersed by wind
Woolly hairs, plumes, wings
Fleshy fruits - Attract animals and provide them with food
Peaches, cherries, tomatoes
Accessory fruit - Bulk of fruit is not from ovary, but from receptacle
Apples

28. Structure and Function of Fruits
Biology, 9th ed, Sylvia Mader
Structure and Function of Fruits
Chapter 28
Reproduction in Plants

29. Biology, 9th ed, Sylvia Mader
Compound Fruits
Chapter 28
Reproduction in Plants
Compound fruits develop from several individual ovaries
Aggregate Fruits
Ovaries are from a single flower
Blackberry
Multiple Fruits
Ovaries are from separate flowers clustered together

30. Biology, 9th ed, Sylvia Mader
Seed Germination
Chapter 28
Reproduction in Plants
When seed germination occurs, the embryo resumes growth and metabolic activity
Length of time seeds retain their viability is quite variable
Some seeds do not germinate until they have been through a dormant period
Temperate zones - Cold Weather
Deserts - Rain

31. Biology, 9th ed, Sylvia Mader
Seed Germination
Chapter 28
Reproduction in Plants
Environmental requirements for seed germination
Availability of oxygen for metabolic needs
Adequate temperature for enzyme activity
Adequate moisture for hydration of cells
Light (in some cases)
Respiration and metabolism continue throughout dormancy, but at a reduced level

32. Seed Structure and Germination in the Common Garden Bean
Biology, 9th ed, Sylvia Mader
Seed Structure and Germination in the Common Garden Bean
Chapter 28
Reproduction in Plants

33. Corn Kernel Structure and Germination
Biology, 9th ed, Sylvia Mader
Corn Kernel Structure and Germination
Chapter 28
Reproduction in Plants

34. Asexual Reproduction in Plants
Biology, 9th ed, Sylvia Mader
Asexual Reproduction in Plants
Chapter 28
Reproduction in Plants
Plants contain nondifferentiated meristem tissue
Allows them to reproduce asexually by vegetative propagation
Plant hormone auxin:
Can be used to cause roots to develop
Expands the list of plants that can be propagated from cuttings

35. Asexual Reproduction in Plants
Biology, 9th ed, Sylvia Mader
Asexual Reproduction in Plants
Chapter 28
Reproduction in Plants

36. Tissue Culture of Plants
Biology, 9th ed, Sylvia Mader
Tissue Culture of Plants
Chapter 28
Reproduction in Plants
Tissue culture is the growth of a tissue in an artificial liquid or solid culture medium
Plant cells are totipotent
Meristem culture
Auxins and cytokinins allow many new shoots to develop from a single shoot tip
Virus-free clonal plants
Suspension Culture
Rapidly growing calluses are cut into small pieces and shaken into a liquid nutrient medium
Single cells or small clumps break off and form a suspension

37. Tissue Culture in Plants
Biology, 9th ed, Sylvia Mader
Tissue Culture in Plants
Chapter 28
Reproduction in Plants

38. Biology, 9th ed, Sylvia Mader
Genetic Engineering
Chapter 28
Reproduction in Plants
Traditionally, hybridization was used to produce plants with desirable traits
Crossing different varieties of plants
Transgenic plants can now be produced by placing foreign genes into a plant
Agricultural plants with improved traits
Pest or insecticide resistant
Commercial Products
Human hormones, antibodies

39. Biology, 9th ed, Sylvia Mader
Chapter 28
Maize
Reproduction in Plants

40. Genetically Engineered Plants
Biology, 9th ed, Sylvia Mader
Genetically Engineered Plants
Chapter 28
Reproduction in Plants

41. Biology, 9th ed, Sylvia Mader
Review
Chapter 28
Reproduction in Plants
Reproductive Strategies
Alternation of generations
Adaptation to a land environment
Flowers
Pollination
Fertilization
Seed Development
Fruit
Seed Germination
Asexual Reproduction
Tissue Culture

42. Biology, 9th ed, Sylvia Mader
Chapter 28
Ending Slide Chapter 28
Reproduction in Plants
Reproduction in Plants