1. Double fertilization involves the union of two sperm cells with an egg and polar nuclei in flowering plants. One sperm fertilizes the egg to form the zygote, and the other fertilizes the polar nuclei to form the endosperm. 2. The zygote will develop into the embryo, and the endosperm provides nutrition for the developing seed. This double fertilization is unique to flowering plants.

1. Double Fertilization This process involves the joining of a female gametophyte (embryo sac) with two male gametes (sperm). The union in flowering plants of two sperm nuclei. One sperm nucleus unites with the egg to form the diploid zygote, from which the embryo develops, and the other unites with two polar nuclei to form the triploid, primary endosperm nucleus.

3. Plant Reproduction

4. Introduction A flower has a set of adaptations Petals have modified leaves Entire flower is a highly modified branch Flower shape, scent, color attracts insects , thereby ensuring the reproduction of the plant

6. Flower Function To produce seeds for reproduction

7. Terminology Whorl Arrangement of three or more leaves, petals, or other organs radiating from the plant Non-essential flower parts Not directly involved in reproduction Essential flower parts Directly involved in reproduction

8. Parts of the Flower Receptacle Base of the flower

9. Parts of the Flower Sepals Non-essential parts of the flower Compose the first whorl Collectively known as the calyx

11. Parts of the Flower Petals Non-essential parts of the flower Compose the second whorl Collectively known as the corolla

13. Parts of the Flower Stamen Essential flower parts Compose the third whorl Male reproductive organ Anther : Produces pollen (contains sperm cells) Filament : Supports the anther

16. Parts of the Flower Carpels Essential flower parts Compose the last, fourth whorl Usually fused to make a single pistil Female reproductive organ

17. Parts of the flower Female reproductive organ Ovary : Swollen base of the pistil (contains ovules, which contain egg cells) Style : Stalk of the pistil Stigma : Tip of the pistil, sticky to capture falling pollen

21. Types of Flowers Perfect Has both pistils and stamens in the same flower Have all 4 whorls of modified leaves Imperfect Has either pistil or stamens in the same flower Missing one or more flower parts Two types Monoecious Dioecious

22. Imperfect Flowers Monoecious “ Same house” Separate male and female flowers on the same plant Example Corn

26. Imperfect Flowers Dioecious “ Two houses” Flowers are all male or all female on the same plant Example Ginko tree Most are male Female produces seeds with foul odor

28. Male Ginko Tree

32. Terminology Gametophyte Haploid form of a plant that produces gametes Sporophyte Diploid state of a plant that develops from the zygote

33. Sexual Activity in Flowers It's the flower's job to produce the male and female gametophytes Male gametophyte - 2 cells (pollen grain) Female gametophyte - 7 cells (embryo sac)

34. Male Gametophyte Formation Microsporangia or microspore mother cell Diploid Found in a pollen sac of the anther Undergoes meiosis Produces 4 microspores (haploid) Each microspore undergoes mitosis to produce microgametophytes (pollen grains each with two cells)

35. Male Gametophyte Formation Pollen grain Hard bumpy outer cell wall Contains 2 cells Tube cell Forms the pollen tube Generative cell Suspended in the tube cell Undergoes mitosis to produce two sperm cells

37. A B C

39. Female Gametophyte Formation Megasporangia or megaspore mother cell Diploid Found in the ovary Undergoes meiosis Produces 1 megaspore (the other 3 die) Megaspore undergoes mitosis 3 times to produce the megagametophyte (embryo sac composed of 8 nuclei and 7 cells)

40. Female Gametophyte Formation Megagametophyte 3 antipodals Function in nutrition 2 polar nuclei Function in nutrition 1 egg Female sex cell 2 synergids “ Helper cells”

42. Male Gametophyte Female Gametophyte

44. Summary of Gametophytes

45. Pollination Process where pollen is transferred from the anther to the stigma of a flower of the same species

46. Types of Pollination Cross Pollination Pollen travels from one anther of one plant to stigma of another plant

47. Types of Pollination Self pollination Pollen travels from anther to stigma of the same flower or the same plant

48. Methods of Pollination Wind pollination Depends on: The release of a lot of pollen Sufficient wind Flower needs to be within traveling distance

50. Methods of Pollination Pollination via animals Depends on… Brightly colored petals Distinctive scents Good tasting nectar (solutions of sugars and aa) Attachment of pollen to the animal in hopes of successful transfer

51. Double Fertilization Union of gametes in plants Type of sexual reproduction

52. Process of Double Fertilization 1. Pollen grain germinates Begins to grow

53. Process of Double Fertilization 2. The tube cell of the pollen grain initiates the growth of a long tube through the style toward the ovule.

54. Process of Double Fertilization 3. The generative cell of the pollen grain divides by mitosis to produce two, haploid , sperm cells

55. Process of Double Fertilization 4. The pollen tube continues to grow through the ovary and into the micropyle.

59. Process of Double Fertilization 5. Sperm enter the embryo sac through the micropyle 6. First sperm fuse with the egg and forms a zygote (2N), which will eventually develop into the embryo . 7. Second sperm fuses with the two polar nuclei (3N) which eventually develop into the endosperm

60. Process of Double Fertilization

61. Summary of Double Fertilization

62. The Seed Fertilized ovule is called a seed

64. Structure of Seeds Dicots - Beans 1. Seed Coat Modified integuments Contains hormones that maintain seed dormancy until conditions are right for germination 2. Hilum Point where the seed attaches to the ovary Usually leaves a scar to the ovary

66. Structure of Seeds - Dicots 3. Micropyle Location where the sperm entered the ovule Tiny hole is visible on the seed coat 4. 2 cotyledons Endosperm Store food for the embryo until it is ready to photosythesize

69. Structure of Seeds - Dicots 5. Embryo - “Baby plant” Radicle - Embryonic root Part of the embryo that emerges first Plumule - Surrounds the tip of the stem ( epicotyl ), both together make up the embryonic leaves Hypocotyl - Embryonic stem Space between the radicle and plumule

72. Structure of Seeds Monocots - Corn 1-Seed coat Modified integuments Contains hormones that maintain seed dormancy until conditions are right for germination 2-Hilum Point where the seed attaches to the ovary Scar left on the seed coat

73. Structure of Seeds Monocots - Corn 3-Micropyle Where the sperm entered the ovule Tiny hole is visible on the seed coat 4- 1 cotyledon Absorbs nutrients from the endosperm Passes nutrients to the embryo until plant is ready to photosynthesize

74. Structure of Seeds Monocots - Corn 5- Embryo - “Baby plant” Radicle Embryonic root Plumule (along with epicotyl) Embryonic leaves Hypocotyl Embryonic stem

77. Exercise

78. Types of Fruit Definition Ovary is called the fruit

79. 1-Simple Fruit Developed from ONE ovary with a single pistil Examples of simple fruit Fleshy – peach, plum, apple Dry - nuts

80. 2-Aggregrate Fruit Derived from ONE flower with several to many pistils Individual pistils mature as a clustered unit on a single receptacle Examples Raspberries, Strawberries

81. 3-Multiple Fruit Derived from a cluster of flowers growing together Develops from ovaries of several flowers borne/fused on the same stalk Examples Pineapples, figs, pine

82. Dispersal of fruits & seeds Animals physically carry seeds or swallow fruits, then excrete the seeds elsewhere Example Burrs on fur, birds eating seeds

83. Dispersal of fruits & seeds Wind carries wing-like seeds Example Helicopter winged seeds

84. Dispersal of fruits & seeds 3. Water carries seeds with air chambers Example - Coconut Plants such as Pond Iris grow in or near freshwater. The seed pods break open when they ripen. Those which fall into the water float away. The seeds may be dispersed long distances in this way. They can either germinate in the water or when they become stranded on mud.

86. Germination of seeds Process where growth emerges from a period of dormancy A seed needs to go through a dormancy period in order to avoid prolonged droughts or intense cold

87. Conditions for Germination 1-Water - Softens seed coat & activates enzymes 2-Oxygen - Required for cellular respiration 3-Warmth Temperature of at least 50F to prevent freezing of tissue 4-Light – influences growth

88. Process of Germination 1-Emergence of radicle , which ruptures the seed coat 2-The shoot begins to grow 3- Embyronic leaves begin to photosynthesize 4- Seedling continues to grow from meristematic regions and matures in to a plant

89. Monocot Germination Cotyledon remain underground Epicotyl emerges first

91. Dicot Germination Cotyledons emerge Hypocotyl emerges first

94. Asexual Reproduction Vegetative Propagation Formation of new individuals from the cell(s) of a single parent. Very common in plants; less so in animals All plant organs have been used, but stems are the most common

95. 1. Runners Stolons Horizontal above-ground stems Strawberries Clones itself during springtime by producing stolons around the mother plant

96. 2. Rhizomes Produce underground stems Raspberry Periodically produce adventitious roots and a new above ground shoot.

97. 3. Tuber M odified rhizomes Potato Swollen ends of rhizomes Develop when specialized stem branches grow down into the ground and swell up with starch containing cells Buds on the tubers will grow into new plants.

98. 4. Bulbs Underground stem Tulip, onions, chives, lilies Multiple naturally Each bulb has a very short stem which is surrounded by fleshy leaves

99. 5. Plant Propagation A. Cuttings Houseplants Process Cut stem Put in water Wait until roots grow Then…plant in soil

100. Plant Propagation B. Grafting Apple tree Two types of apples on the same tree Vascular cambium must connect/match Related species

101. Plant Propagation C. Tissue culture Houseplants Process Grown in a petri dish Then planted in soil