The Intricacies of Plant Reproduction: Fruits and Flowers Explained
Explore the fascinating world of plant reproduction in this overview of fruits and flowers. Discover how these remarkable structures are designed for effective sexual selection and reproductive success in angiosperms. Learn about the different methods of reproduction, including asexual propagation and sexual reproduction through meiosis. Dive into the lifecycle of flowering plants, including the role of gametes, fertilization, and seed development. Understand the complexity of flower structures, the differentiation between perfect and imperfect flowers, and the significance of various reproductive organs.
The Intricacies of Plant Reproduction: Fruits and Flowers Explained
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Presentation Transcript
Chapter 6 Overview Fruits & Flowers Chapter 6 Overview http://www.ddflowers.com.sg/Products/Thumbnail/192-GW016-LO.JPG
What are fruits & flowers for? • When you bite into a juicy peach or when you give someone a bouquet of daisies or roses- you probably aren’t thinking: “ Wow, these are marvelous structures designed to facilitate effective sexual selection & maximize reproductive success in angiosperm plants!” • From now on- this is what you should be pondering!
Plant reproduction is complex • Unlike humans, who reproduce only sexually, with a single method, plants have a variety of ways of reproducing. • Asexual • Sexual
Asexual Reproduction: • Also known as ‘ vegetative propagation” • Offspring are clones of parent • Genetically identical • Cell division by mitosis
Review: Stages of Mitosis Divided into 4 phases: 1. PROPHASE 2. METAPHASE 3. ANAPHASE TELOPHASE Memory aid: Pro met Anna on the telophone
http://jabberwiki.wikispaces.com/file/view/mitosis1.gif/53565174http://jabberwiki.wikispaces.com/file/view/mitosis1.gif/53565174
Can you find a cell in each phase of mitosis? http://www.bioweb.uncc.edu/1110Lab/notes/notes1/labpics/Onion%20Prophase%20and%20%20Metaphase%2020x.jpg
Example of Plant asexual reproduction: 1. Strawberry plants- sends out stolons or runners • Only need a few plants to start a strawberry bed. http://www.smallkitchengarden.net/wp-content/uploads/c37d59f25bed5e2.jpg
Examples of Plant asexual reproduction: 2. Kalanchoe diagremontiana “walking fern” plant • Produces “plantlets” on the edges of leaves- a leaf that touches the ground grows into a new plant http://pics.davesgarden.com/pics/WUVIE_1189126100_673.jpg
Example of Plant asexual reproduction: 3. Quaking aspen trees • Adventitious roots make a large group of trees • The whole group is called a “clone” http://www.coloradotreefarmnursery.com/photogallery/Deciduous%20Trees/Aspen/Aspen%201/Aspen.jpg
Sexual reproduction in plants • Sexual reproduction uses process of Meiosis • Gametes- are Haploid cells • Spores, Sperm (pollen), eggs (ovule) • Form a Zygote – the fertilized egg • Genetic recombination of genes produces a unique individual.
Review: Sexual Reproduction in plants has “Alternation of generations” • life cycle with 2 different generations. • a Haploid Gametophyte produces gametes. • Gametes unite and give rise to a Diploid Sporophyte, which produces spores or haploid cells
REVIEW: In flowering seed plants - angiosperms: • 2 fertilization events take place: • one sperm fertilizes the egg to form the diploid zygote of the new individual, • the other sperm fertilizes the polar nuclei to form the triploid endosperm, a nutritive tissue (the FRUIT). • Together with maternal sporophyte tissue, these make up the seed.
Flowers, fruit & seeds • Only in angiosperm plants • With nearly 250,000 species- there is great variety in flower structure • All flowers sit at the top of the stem part called the peduncle http://content.answers.com/main/content/img/Gardeners/f0186.jpg
Inflorescence • A peduncle bearing a group of flowers • Several different types shown below: http://www3.hcs.ohio-state.edu/wiki/images/d/d2/Inflor.GIF
Flowers • highly specialized reproductive organs, • reproductive functions include: • Advertising (attracting pollinators) • pollination • fertilization • seed development • Seeds dispersal
Parts of a flower Male parts: -stamen Female parts: -Carpel, also called pistil 2 other modified leaves: -Sepals -Petals http://andromeda.cavehill.uwi.edu/Plant%20Propagation%20Practical%20Photos/Generalised_Flower_Diagram.jpg
Complete & Incomplete Flowers • Compete flower- if it contains all four types of modified leaves : • Sepals • Petals • Stamens • Carpels • Incomplete Flowers- lack one or more of these modified leaves
Perfect flowers • Perfect- also known asbisexual flowershave both male (stamens) & carpels (pistil) parts on same flower. • Roses • Olives (also has staminate flowers) • Apples • Cherries • Nectarines
Imperfect- unisex flower • Has either stamen or carpel (pistil) –not both • Has only one set of reproductive organs • Two types of imperfect flowers (either male or female) • Staminate flowers contain only stamens, the male reproductive part of the flower. • Pistillate flowers only contain the pistil, or female, reproductive
Flowers have ovaries in different positions: • The location of the ovary to the sepals & petals: *Superior *Semi-Inferior *Inferior
Types of plants: • Monoecious plants have male and female parts on the same plant • (corn, cucurbits, birch, walnut). • Dioecious plants have male and female flowers on separate plants • (hemp, American holly, hazel nut).
Apples have perfect flowers • Green sepals (6) protect the bud before the flower opens. • Petals (1) white, -are highly visible to the insect pollinators. • Male parts -filament (5) and anther (4). Pollen is produced in its anthers • Female parts: stigma (2), style & ovary (7)). • Pollen land on the stigma, forms a pollen tube that grows down the style (3) to the ovary (7), where it releases the male gamete & fertilizes the ovule in the ovary. • The fertilized ovule develops into a seed and the ovary typically develops into the fruit. quorumsensing.ifas.ufl.edu/HCS200/Breefrme.html
Blackberries have perfect flowers www.cobaltinc.com/.../Classify/classifi.htm
How to Identify Male and Female Zucchini Flowers Female Flower Male Flower
Imperfect flowers: Hazelnut- separate male & female flowers on same plant
Grasses -monocots • flowers of grasses are less showy (“fescue flower”). • produce significant amounts of pollen in their anthers (4). • Carried by wind, pollen lands on sticky feather-like stigma receptacles (2). • Sepals and petals of grasses have evolved into three layers of protective bracts -glume, palea, and lemma (9). quorumsensing.ifas.ufl.edu/HCS200/Breefrme.html
Fruit: • is a ripened (mature) ovary • Where seeds develop & are found • serves as protection • Means of dispersal for the seeds http://biology.clc.uc.edu/courses/bio106/angio.htm
Some types of fruits: -Simple fruits -from one ovary in one flower. Examples: walnut, tomato, orange, cherry, apple, dandelion, and maple “helicopter.” -Different types of simple fruit- each has its own official name. Aggregate fruits arise from several ovaries in one flower. Examples include raspberry and strawberry. Multiple fruits arise from ovaries in several, tightly-clustered flowers which grow together into one “fruit.” Examples include pineapple, mulberry, and breadfruit. http://biology.clc.uc.edu/courses/bio106/angio.htm
Some activities: • Fruits game • Dissect flower
Your assignment: • Read Ch 6 • Section review questions Page 130, # 1 & 3 Page 134 # 1- 3 Page 143 # 1- 3 • Read pages 137 & 138 - boxes about Apomixis, & Tropical Fruits • Page 144, Thought question: #1