Sexual Reproduction in Plants Slide 1 Sexual Reproduction in Plants

Stigma Ovary  Fruit Anther Style Ovule  Seed Filament Ovule Petal Slide # 2 Flower Structure Stigma Ovary  Fruit Anther Style Ovule  Seed Filament Ovule Petal Sepal Pistil (female Part) Stigma Style Ovary Stamen (Male Part) Anther Filament Receptacle Ovary

Structure of a Flower 1.Pistil:female reproductive structure Slide # 3 Filament Anther Stigma Style Ovary Pistil Petal Sepal Ovule Stamen 1.Pistil:female reproductive structure Stigma: sticky tip; traps pollen Style: slender tube; transports pollen from stigma to ovary Ovary: contains ovules; ovary develops into fruit Ovule: contains egg cell which develops into a seed when fertilized

Structure of a Flower Stamen: male reproductive structure Slide # 4 Filament Anther Stigma Style Ovary Pistil Petal Sepal Ovule Stamen Stamen: male reproductive structure Filament: thin stalk; supports anther Anther: knob-like structure; produces pollen Pollen: contains microscopic cells that become sperm cells

Slide # 5

Perfect & Imperfect Flowers Slide # 6 Perfect Flower ~ has pistil & stamen Imperfect Flower ~ only one sex Which is male? Female?

 Structure of a Flower Slide # 7 Filament Anther Stigma Style Ovary Pistil Petal Sepal Ovule Stamen Sepals: encloses & protects flower before it blooms Petals: usually colorful & scented; attracts pollinators

What are the functions of each part? Slide # 8 What are the functions of each part?

Pollination Slide # 9 The transfer of pollen grains from the anther to the stigma. Pollination may be aided by wind, insects, and birds. In some instances, the colored petals act as a visual attractant for insects. If pollination occurred in a dry environment, the pollen would not dehydrate (dry up) due to a thick wall that surrounds it. Two types of pollination: 1. Self-Pollination 2. Cross-Pollination

Allows for variations due to the combination of two different plants. Self-Pollination Slide # 10 The transfer of pollen grains from the anther to the stigma of the same plant. Cross-Pollination The transfer of pollen grains from the anther of a flower on one plant to the stigma of a flower on a different plant. Allows for variations due to the combination of two different plants.

Pollen tube is an adaptation for internal fertilization. Slide # 11 Following pollination, the pollen grain germinates to the stigma and forms a pollen tube. Pollen tube is an adaptation for internal fertilization. 2 Haploid sperm cells travel down the pollen tube and only one fertilizes the egg in the ovule.

Fertilization and Embryo Development Slide # 12 The union of a sperm cell and an egg cell results in the formation of a zygote The zygote undergoes development resulting in the formation of an embryo (ripened ovule) The ripened ovule (embryo) develops into the seed The ripened ovary develops into the fruit

Structure of a Seed (embryo) Slide # 13 Structure of a Seed (embryo) Hypocotyl: Develops into roots and in some species lower stem. Radical: Develops in roots Epicotyl: Develops into leaves and upper stem Cotyledon: Stored food for early development of embryo (seed leaves)

Slide # 14 Structure of a Seed Epicotyl

forms from outer layer of ovule protects embryo Slide # 15 Seed coat: forms from outer layer of ovule protects embryo Endosperm: food storage tissue (the other sperm creates this triploid (3n) structure when it fertilizes 2 polar bodies from oogenesis)

Monocots – seeds with one cotyledon (corn) Slide # 16 Monocots & Dicots Monocots – seeds with one cotyledon (corn) Dicots – seeds with two cotyledons (bean, peanut)

Germination and Growth Slide # 17 Germination and Growth Fruits are specialized structures which aid in seed dispersal. Seeds develop inside the fruit. If the temperature and moisture levels are sufficient, the dispersed seeds will germinate (activate and grow). Growth in most plants occurs in the meristems. The organs of a plant are developed in the meristems. Apical Meristems are found in the tips of roots and stems and cause the plant to grow in height. Lateral Meristems are between the xylem and phloem and cause the plant to grow in diameter (get wider).

Plant Responses and Adaptations Slide # 18 Plant Responses and Adaptations

Hormone Action on Plants Hormone-producing cells Hormone Action on Plants Slide #19 A. Plant cells can produce hormones (chemical messengers that travel throughout the plant causing other cells called target cells to respond) B. In plants, hormones control: Plant growth & development Plant responses to environment Movement of hormone Target cells Cells in one blooming flower signals other blooms using hormones to open.

High Auxin ~ stimulates stem growth ~ inhibits root growth Plant Hormones Slide # 20 Auxin High Auxin ~ stimulates stem growth ~ inhibits root growth Low Auxin ~ reverse effect Gibberellin Increases stem growth Increases fruit and seed development

Plant cells will send signals to one another to tell them: Slide # 21 Plant cells will send signals to one another to tell them: When trees to drop their leaves. When to start new growth. When to cause fruit to ripen. When to cause flowers to bloom. When to cause seeds to sprout. Leaf Drop Tree Budding Fruit Ripening Cactus Blooming Sprouting Corn Seeds

Ethylene causes Fruit to Ripen Slide # 22 Ethylene causes Fruit to Ripen Fruit tissues release a small amount of ethlyene Ethylene is a gaseous hormone Causes fruits to ripen As fruit become ripe, they produce more and more ethlyene, accelerating the ripening process Fruit picked before ripened….spray w/ethylene at destination to ripen Ethylene released by apples and tomatoes causes fruit to age quickly. What type of feedback?

Slide # 23 Plant Tropisms Tropism: the way a plant grows in response to stimuli in the environment caused by an unequal distribution of auxin. Phototropism: growth response to light -Plants bend towards light Geotrophism: growth response to gravity -plant roots grow down with gravity, shoots (stems) grow up against gravity and out of the soil. Thigmotropism: growth response to touch -vines grow up around trees, venus flytrap closes when leaves are touched

Thigmotrophism Phototropism Thigmotrophism Slide # 24 What type of tropism is shown in these pictures? Phototropism Geotropism Thigmotrophism Phototropism Geotropism Thigmotrophism