1. Angiosperm Reproduction and Biotechnology
Chapter 38
Angiosperm Reproduction and Biotechnology

2. Overview: Flowers of Deceit
____________ help angiosperms to reproduce sexually with distant members of their own species
For example, male Campsoscolia wasps mistake Ophrys flowers for females and attempt to mate with them
The flower is pollinated in the process
Unusually, the flower does not produce nectar and the male receives no benefit
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3. Figure 38.1
Figure 38.1 Why is this wasp trying to mate with this flower?

4. ___________________ are common between plants and other species
Many angiosperms lure insects with _________; both plant and pollinator benefit
___________________ are common between plants and other species
___________________can reproduce sexually and asexually
___________________are the most important group of plants in terrestrial ecosystems and in agriculture
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5. Concept 38.1: Flowers, double fertilization, and fruits are unique features of the angiosperm life cycle
Plant lifecycles are characterized by the alternation between a multicellular __________(n) generation and a multicellular ___________(2n) generation
Diploid _____________(2n) produce spores (n) by meiosis; these grow into haploid gametophytes (n)
________produce haploid gametes (n) by mitosis; _____________of gametes produces a sporophyte
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6. In angiosperms, the __________________ is the dominant generation, the large plant that we see
The ________________ are reduced in size and depend on the sporophyte for nutrients
The angiosperm life cycle is characterized by “three Fs”:___________________________, and ______________
For the Discovery Video Plant Pollination, go to Animation and Video Files.
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7. Structure of an idealized flower
Figure 38.2a
Stamen
Stigma
Carpel
Anther
Style
Filament
Ovary
Sepal
Petal
Figure 38.2 An overview of angiosperm reproduction.
Receptacle
(a)
Structure of an idealized flower

8. Germinated pollen grain (n) (male gametophyte)
Figure 38.2b
Anther
Germinated pollen grain (n) (male gametophyte)
Ovary
Pollen tube
Ovule
Embryo sac (n) (female gametophyte)
FERTILIZATION
Egg (n)
Sperm (n)
Zygote (2n)
Mature sporophyte plant (2n)
Key
Figure 38.2 An overview of angiosperm reproduction.
Seed
Haploid (n)
Germinating seed
Diploid (2n)
Seed
Embryo (2n) (sporophyte)
(b)
Simplified angiosperm life cycle
Simple fruit

9. Flower Structure and Function
Flowers are the reproductive shoots of the angiosperm sporophyte; they attach to a part of the stem called the _______________
Flowers consist of four floral organs: __________ ______________________________
_____________ and ___________ are reproductive organs; sepals and petals are _______________
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10. A carpel has a long ________ with a ________ on which pollen may land
A stamen consists of a filament topped by an __________ with pollen sacs that produce ______
A carpel has a long ________ with a ________ on which pollen may land
At the base of the style is an __________ containing one or more ____________
A single carpel or group of fused carpels is called a ______________
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11. ________________contain all four floral organs
________________ lack one or more floral organs, for example stamens or carpels
Clusters of flowers are called ________________
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12. Development of Male Gametophytes in Pollen Grains
Pollen develops from _________________within the ________________, or pollen sacs, of anthers
Each microspore undergoes mitosis to produce two cells: the ____________cell and the ____ cell
A pollen grain consists of the two-celled ______ ________________and the spore wall
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13. If pollination succeeds, a _____________ produces a _______________ that grows down into the ovary and discharges two sperm cells near the embryo sac
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14. Female gametophyte (embryo sac)
Figure 38.3
Development of a male gametophyte (in pollen grain)
(a)
(b)
Development of a female gametophyte (embryo sac)
Microsporangium (pollen sac)
Megasporangium
Microsporocyte
Ovule
Megasporocyte
MEIOSIS
Integuments
Microspores (4)
Micropyle
Surviving megaspore
Each of 4 microspores
MITOSIS
Ovule
Antipodal cells (3)
Male gametophyte (in pollen grain)
Generative cell (will form 2 sperm)
Figure 38.3 The development of male and female gametophytes in angiosperms.
Polar nuclei (2)
Female gametophyte (embryo sac)
Egg (1)
Nucleus of tube cell
Integuments
Synergids (2)
20 m
Ragweed pollen grain (colorized SEM)
Key to labels
Embryo sac
Haploid (n)
75 m
100 m
(LM)
Diploid (2n)
(LM)

15. Development of a male gametophyte (in pollen grain) (a)
Figure 38.3a
Development of a male gametophyte (in pollen grain)
(a)
Microsporangium (pollen sac)
Microsporocyte
MEIOSIS
Microspores (4)
Each of 4 microspores
MITOSIS
Male gametophyte (in pollen grain)
Generative cell (will form 2 sperm)
Figure 38.3 The development of male and female gametophytes in angiosperms.
Nucleus of tube cell
20 m
Key to labels
Ragweed pollen grain (colorized SEM)
Haploid (n)
75 m
(LM)
Diploid (2n)

16. Development of Female Gametophytes (Embryo Sacs)
The _______________, or female gametophyte, develops within the ovule
Within an ovule, two integuments surround a ___________________
One cell in the megasporangium undergoes meiosis, producing four _______________, only one of which survives
The megaspore divides, producing a large cell with ____________ nuclei
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17. This cell is partitioned into a ________________ _______________________, the embryo sac
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18. Female gametophyte (embryo sac)
Figure 38.3b
(b)
Development of a female gametophyte (embryo sac)
Megasporangium
Ovule
Megasporocyte
MEIOSIS
Integuments
Micropyle
Surviving megaspore
MITOSIS
Ovule
Antipodal cells (3)
Figure 38.3 The development of male and female gametophytes in angiosperms.
Polar nuclei (2)
Female gametophyte (embryo sac)
Egg (1)
Integuments
Synergids (2)
Key to labels
Embryo sac
Haploid (n)
100 m
Diploid (2n)
(LM)

19. Pollination
In angiosperms, _______________ is the transfer of pollen from an anther to a stigma
Pollination can be by ______________________
Wind-pollinated species (e.g., grasses and many trees) release ___________________________
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20. Abiotic Pollination by Wind Pollination by Bees
Figure 38.4a
Abiotic Pollination by Wind
Pollination by Bees
Common dandelion under normal light
Hazel staminate flowers (stamens only)
Figure 38.4 Exploring: Flower Pollination
Hazel carpellate flower (carpels only)
Common dandelion under ultraviolet light

21. Pollination by Moths and Butterflies Pollination by Flies
Figure 38.4b
Pollination by Moths and Butterflies
Pollination by Flies
Pollination by Bats
Anther
Moth
Fly egg
Stigma
Blowfly on carrion flower
Long-nosed bat feeding on cactus flower at night
Moth on yucca flower
Pollination by Birds
Figure 38.4 Exploring: Flower Pollination
Hummingbird drinking nectar of columbine flower

22. Coevolution of Flower and Pollinator
_________________ is the evolution of interacting species in response to changes in each other
Many flowering plants have coevolved with specific _________________
The _______________________ of flowers often correspond to the pollen transporting parts of their animal pollinators
For example, Darwin correctly predicted a moth with a 28 cm long tongue based on the morphology of a particular flower
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23. Figure 38.5
Figure 38.5 Coevolution of a flower and an insect pollinator.

24. Double Fertilization
After landing on a receptive stigma, a pollen grain produces a _________________ that extends between the cells of the style toward the ovary
_____________________ results from the discharge of two sperm from the pollen tube into the embryo sac
One sperm fertilizes the ____________, and the other combines with the ______________, giving rise to the triploid food-storing ___________ (3n)
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25. Endosperm nucleus (3n) (2 polar nuclei plus sperm)
Figure 1 2 3
Pollen grain
Stigma
Endosperm nucleus (3n) (2 polar nuclei plus sperm)
Pollen tube
Ovule
Polar nuclei
2 sperm
Style
Egg
Ovary
Zygote (2n)
Ovule
Synergid
Polar nuclei
Figure 38.6 Growth of the pollen tube and double fertilization.
2 sperm
Egg
Micropyle

26. Seed Development, Form, and Function
After double fertilization, each ovule develops into a ______________
The ovary develops into a ____________ enclosing the seed(s)
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27. Endosperm Development
Endosperm development usually precedes _____________ development
In most monocots and some eudicots, __________________ stores nutrients that can be used by the seedling
In other eudicots, the food reserves of the endosperm are exported to the _______________
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28. Embryo Development
The first mitotic division of the zygote splits the fertilized egg into a _________and a __________
The basal cell produces a multicellular ______________ , which anchors the embryo to the parent plant
The terminal cell gives rise to most of the __________
The ___________ form and the embryo elongates
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29. Ovule Proembryo Endosperm nucleus Suspensor Integuments Cotyledons
Figure 38.7
Ovule
Proembryo
Endosperm nucleus
Suspensor
Integuments
Cotyledons
Zygote
Basal cell
Shoot apex
Root apex
Seed coat
Suspensor
Terminal cell
Figure 38.7 The development of a eudicot plant embryo.
Basal cell
Endosperm
Zygote

30. Structure of the Mature Seed
The embryo and its food supply are enclosed by a hard, protective ______________
The seed enters a state of ________________
A mature seed is only about __________ water
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31. In some eudicots, such as the common garden bean, the embryo consists of the _________ attached to two thick ____________(seed leaves)
Below the cotyledons the embryonic axis is called the ____________ and terminates in the _______ (embryonic root); above the cotyledons it is called the ________________
The _____________ comprises the epicotyl, young leaves, and shoot apical meristem
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32. (a) Common garden bean, a eudicot with thick cotyledons
Figure 38.8
Seed coat
Epicotyl
Hypocotyl
Radicle
Cotyledons
(a) Common garden bean, a eudicot with thick cotyledons
Seed coat
Endosperm
Cotyledons
Epicotyl
Hypocotyl
Radicle
(b) Castor bean, a eudicot with thin cotyledons
Figure 38.8 Seed structure.
Scutellum (cotyledon)
Pericarp fused with seed coat
Endosperm
Coleoptile
Epicotyl
Hypocotyl
Coleorhiza
Radicle
(c) Maize, a monocot

33. The seeds of some eudicots, such as castor beans, have ____________________
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34. A monocot embryo has __________ cotyledon
Grasses, such as maize and wheat, have a special cotyledon called a ________________
Two sheathes enclose the embryo of a grass seed: a ___________covering the young shoot and a _____________covering the young root
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35. Scutellum (cotyledon) Pericarp fused with seed coat
Figure 38.8c
Scutellum (cotyledon)
Pericarp fused with seed coat
Endosperm
Coleoptile
Epicotyl
Hypocotyl
Coleorhiza
Radicle
Figure 38.8 Seed structure.
(c) Maize, a monocot

36. Seed Dormancy: An Adaptation for Tough Times
___________________ increases the chances that germination will occur at a time and place most advantageous to the seedling
The breaking of seed dormancy often requires ___________________, such as temperature or lighting changes
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37. Seed Germination and Seedling Development
Germination depends on imbibition, the uptake of water due to low water potential of the dry seed
The radicle (embryonic root) emerges first
Next, the shoot tip breaks through the soil surface
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38. In many eudicots, a hook forms in the hypocotyl, and growth pushes the hook above ground
Light causes the hook to straighten and pull the cotyledons and shoot tip up
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39. Foliage leaves Cotyledon Epicotyl Hypocotyl Cotyledon Cotyledon
Figure 38.9
Foliage leaves
Cotyledon
Epicotyl
Hypocotyl
Cotyledon
Cotyledon
Hypocotyl
Hypocotyl
Radicle
Seed coat
(a) Common garden bean
Foliage leaves
Figure 38.9 Two common types of seed germination.
Coleoptile
Coleoptile
Radicle
(b) Maize

40. In maize and other grasses, which are monocots, the ________________ pushes up through the soil
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41. Fruit Form and Function
A __________ develops from the ovary
It protects the enclosed seeds and aids in seed dispersal by wind or animals
A fruit may be classified as _____, if the ovary dries out at maturity, or __________, if the ovary becomes thick, soft, and sweet at maturity
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42. Fruits are also classified by their development
__________, a single or several fused carpels
___________, a single flower with multiple separate carpels
___________, a group of flowers called an inflorescence
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43. Pineapple inflorescence
Figure 38.10
Stigma
Style
Carpels
Stamen
Flower
Petal
Ovary
Stamen
Stamen
Sepal
Stigma
Ovary (in receptacle)
Ovule
Ovule
Pea flower
Raspberry flower
Pineapple inflorescence
Apple flower
Each segment develops from the carpel of one flower
Remains of stamens and styles
Carpel (fruitlet)
Stigma
Sepals
Seed
Ovary
Figure Developmental origin of fruits.
Stamen
Seed
Receptacle
Pea fruit
Raspberry fruit
Pineapple fruit
Apple fruit
(a) Simple fruit
(b) Aggregate fruit
(c) Multiple fruit
(d) Accessory fruit

44. An _______________ contains other floral parts in addition to ovaries
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45. Fruit dispersal mechanisms include
___________
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46. Dispersal by Wind Dispersal by Water Dandelion fruit Tumbleweed
Figure 38.11a
Dispersal by Wind
Dandelion fruit
Tumbleweed
Dandelion “seeds” (actually one-seeded fruits)
Winged seed of the tropical Asian climbing gourd Alsomitra macrocarpa
Winged fruit of a maple
Dispersal by Water
Figure Exploring: Fruit and Seed Dispersal
Coconut seed embryo, endosperm, and endocarp inside buoyant husk

47. Dispersal by Animals Fruit of puncture vine (Tribulus terrestris)
Figure 38.11b
Dispersal by Animals
Fruit of puncture vine (Tribulus terrestris)
Squirrel hoarding seeds or fruits underground
Ant carrying seed with nutritious “food body” to its nest
Figure Exploring: Fruit and Seed Dispersal
Seeds dispersed in black bear feces

48. Concept 38.2: Flowering plants reproduce sexually, asexually, or both
Many angiosperm species reproduce both ______________ and _____________
_____________ reproduction results in offspring that are genetically different from their parents
_______________________ results in a clone of genetically identical organisms
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49. Mechanisms of Asexual Reproduction
_________________, separation of a parent plant into parts that develop into whole plants, is a very common type of asexual reproduction
In some species, a parent plant’s root system gives rise to _____________________ that become separate shoot systems
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50. Figure 38.12
Figure Asexual reproduction in aspen trees.

51. _______________ is the asexual production of seeds from a diploid cell
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52. Advantages and Disadvantages of Asexual Versus Sexual Reproduction
Asexual reproduction is also called ________ ________________________
Asexual reproduction can be beneficial to a successful plant in a _____________ environment
However, a clone of plants is ______________ to local extinction if there is an environmental change
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53. However, only a __________ of seedlings survive
Sexual reproduction generates _____________ that makes evolutionary adaptation possible
However, only a __________ of seedlings survive
Some flowers can _______________ to ensure that every ovule will develop into a seed
Many species have evolved mechanisms to _________________ selfing
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54. Mechanisms That Prevent Self-Fertilization
Many angiosperms have mechanisms that make it difficult or impossible for a flower to self-fertilize
________________ species have staminate and carpellate flowers on separate plants
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55. Staminate flowers (left) and carpellate flowers (right)
Figure 38.13
Staminate flowers (left) and carpellate flowers (right)
of a dioecious species
(a)
Figure Some floral adaptations that prevent self-fertilization.
Stamens
Styles
Styles
Stamens
Thrum flower
Pin flower
(b) Thrum and pin flowers

56. Others have stamens and carpels that mature at _____________or are arranged to prevent selfing
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57. Stamens Styles Styles Stamens Thrum flower Pin flower Figure 38.13c
Figure Some floral adaptations that prevent self-fertilization.
Thrum flower
Pin flower

58. The most common is ____________________, a plant’s ability to reject its own pollen
Researchers are unraveling the molecular mechanisms involved in self-incompatibility
Some plants reject pollen that has an _________ matching an allele in the stigma cells
Recognition of self pollen triggers a ___________ ______________________ leading to a block in growth of a pollen tube
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59. Vegetative Propagation and Agriculture
Humans have devised methods for _________ __________________of angiosperms
Most methods are based on the ability of plants to form ____________________________________
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60. Clones from Cuttings
Many kinds of plants are asexually reproduced from plant fragments called _______________
A ____________ is a mass of dividing undifferentiated cells that forms where a stem is cut and produces adventitious roots
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61. Grafting
A twig or bud can be _____________ onto a plant of a closely related species or variety
The ____________provides the root system
The ____________is grafted onto the stock
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62. Test-Tube Cloning and Related Techniques
Plant biologists have adopted _________methods to create and clone novel plant varieties
A callus of undifferentiated cells can sprout shoots and roots in response to ___________________
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63. (a) (b) (c) Developing root Figure 38.14
Figure Cloning a garlic plant.
(a)
(b)
(c)
Developing root

64. ____________ plants are genetically modified (GM) to express a gene from another organism
____________________ is used to create hybrid plants by fusing protoplasts, plant cells with their cell walls removed
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65. Figure 38.15
Figure Protoplasts.
50 m

66. Concept 38.3: Humans modify crops by breeding and genetic engineering
Humans have intervened in the reproduction and genetic makeup of plants for thousands of years
_______________ is common in nature and has been used by breeders to introduce new genes
Maize, a product of ________________, is a staple in many developing countries
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67. Figure 38.16
Figure Maize: a product of artificial selection.

68. Plant Breeding
________________ can arise spontaneously or can be induced by breeders
Plants with _____________mutations are used in breeding experiments
________________can be introduced from different species or genera
The grain ________________ is derived from a successful cross between wheat and rye
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69. Plant Biotechnology and Genetic Engineering
Plant __________________ has two meanings
In a general sense, it refers to innovations in the use of plants to make useful products
In a specific sense, it refers to use of ___ organisms in agriculture and industry
Modern plant biotechnology is _____________to transfer of genes between closely related species or varieties of the same species
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70. Reducing World Hunger and Malnutrition
Genetically modified plants may increase the quality and quantity of food worldwide
______________crops have been developed that
Produce proteins to _____________them against insect pests
________________________
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71. Nutritional quality of plants is being ___________
For example, “__________” is a transgenic variety being developed to address vitamin A deficiencies among the world’s poor
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72. Cassava roots harvested in Thailand
Figure 38.17
Figure Impact: Fighting World Hunger with Transgenic Cassava
Cassava roots harvested in Thailand

73. Reducing Fossil Fuel Dependency
______________ are made by the fermentation and distillation of plant materials such as cellulose
Biofuels can be produced by rapidly growing crops such as ________________and __________
Biofuels would reduce the net emission of _____, a greenhouse gas
The environmental implications of biofuels are controversial
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74. The Debate over Plant Biotechnology
Some biologists are concerned about risks of releasing __________________(GMOs) into the environment
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75. Issues of Human Health
One concern is that genetic engineering may transfer allergens from a gene source to a plant used for food
Some GMOs have _________________
For example, maize that produces the Bt toxin has 90% less of a cancer-causing toxin than non-Bt corn
Bt maize has less insect damage and lower infection by Fusarium fungus that produces the cancer-causing toxin
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76. Possible Effects on Nontarget Organisms
Many ecologists are concerned that the growing of GM crops might have unforeseen effects on ___________________
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77. Addressing the Problem of Transgene Escape
Perhaps the most serious concern is the possibility of introduced genes escaping into related weeds through ____________________ ____________________
This could result in “_______________” that would be resistant to many herbicides
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78. Efforts are underway to prevent this by introducing
_____________________
_______________________
________________________________ (not transferred by pollen)
________________________________
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