Plant Reproduction A Quick Review

Plants alternate generations. - Gametophyte - haploid plant which produces gametes - gametes - haploid cells which fuse and develop into sporophyte Fern GametophytePollen – Male gametophyte

- Sporophyte - diploid plant which produces spores - spores - haploid cells which develop into gametophyte Plants alternate generations. Fern Sporophyte Spider-plant Sporophyte

alternation of generations

B. Development of pollen and seeds led to the evolution of Seed Plants. - Male gametophyte develops as the pollen grain - Female gametophyte develops inside ovules - eggs develop into seed, a packaged embryo with food supply & protective coat Pumpkin SeedsPollenSunflower Seeds

Plant Reproduction Sexual Reproduction of Seed Plants

A.Gymnosperms (naked-seed) - Gnetophytes, Cycads, Ginkgos, and Conifers 1. Reproduction in Pollen Cones & Seed Cones - have “naked” seeds, or seeds that are not covered, inside of cones Wollemi Pine Red – Pollen Cones Green – Seed cones Black Adler Brown – Pollen Cones Black – Seed cones

- Small male cones produce pollen (male gametophyte) - Larger female cones produce ovules (female gametophyte develops) A.Gymnosperms (naked-seed) - Gnetophytes, Cycads, Ginkgos, and Conifers Female Cone Male Cone

2. Pollination - By wind; pollen is blown on to female cones A.Gymnosperms - Gnetophytes, Cycads, Ginkgos, and Conifers

3. Fertilization - Pollen grows pollen tube and takes 2 haploid sperm into ovule - 1 sperm fertilizes the egg - the other sperm is discarded 4. Seed Development - Egg develops into a zygote (the new sporophyte) within the seed A.Gymnosperms (naked-seed) - Gnetophytes, Cycads, Ginkgos, and Conifers

B. Angiosperms (covered-seed) - all flowering plants 1. Reproduction takes place in flowers - Have covered seeds found inside a fruit that develops from a flower Titan Arum Biggest Flower Strawberry – only fruit with outside seeds! Orchid Smallest Seed

B. Angiosperms (covered-seed) - all flowering plants - Flower is composed of 4 specialized leaves 1. Sepals - covers developing flower, sterile 2. Petals - often brightly colored, sterile 3. Carpel/Pistil - Female reproductive structures 4. Stamen - Male reproductive structures Lily FoxgloveHibiscus

LilyRose

B. Angiosperms - all flowering plants 3. Carpel/Pistil - Female reproductive structures a. Stigma - sticky, receives pollen b. Style - stalk which holds stigma up c. Ovary - contains one or more ovules

B. Angiosperms - all flowering plants 4. Stamen - Male reproductive structures a. Filament - holds anther up b. Anther - produces pollen

B. Angiosperms (board)

Female vs. Male

B. Angiosperms - all flowering plants 2. Pollination - most flowers are pollinated by animals, some by wind - the shape, color, and scent of the flower can tell us what animal pollinates them Birds – Red/Hanging Flowers Insects – can see UV light!

Smells Like… Starfish Flower

The Wasp and Fig Story!

B. Angiosperms - all flowering plants 3. Fertilization - Pollen grows pollen tube and takes 2 haploid sperm into ovule a. Double fertilization occurs - one sperm fertilizes the egg - one sperm fertilizes the endosperm, or nourishment for developing seedling Pollen Tube

B. Angiosperms - all flowering plants 4. Seed and Fruit Development - as seed develops, the ovary surrounding it develops into a fruit - not all fruit is fleshy/edible!

The Fleshy Fruits

The Dry Fruits

Watermelon in crazy shapes!

So what is a fruit? Fruits have seeds!

What about fruits without seeds? - Seedless fruits, or ‘Virgin fruits’ -have been genetically engineered by humans not to have seeds! OR -Occur naturally through mutations! (bananas and watermelons!) OR -Seeds don’t develop if their not fertilized! (pineapple and cucumber!) PineappleCucumbersBananas Watermelon

And what is a vegetable? Vegetables are every other part of the plant that isn’t the ovary! Onion – Root! Carrot – Root! Celery – Stem! Lettuce – Leaves! Broccoli – Whole plant! Little flowers at top!

C. Seed Dispersal 1. By Animals a. fruits - animals eat fruit, seed pooped out b. sticky projections - “hitch-hikers” get stuck to animals, eventually fall or are picked off Hitch-Hiker Seeds Fruit Bat/Birds – Widest Dispersal

C. Seed Dispersal 2. By Wind - little and light, may have “wings” -ex. dandelion Dandelion Acer Tumbleweed

C. Seed Dispersal 3. Water -carried by water, buoyant (float) -carried by water, buoyant (float) -ex. coconut

D. Seed Dormancy and Germination 1. Dormancy - embryo is alive, but not growing 2. Germination - early growth stages of plant a. environmental conditions will determine if seed germinates 1. Temperature 2. Moisture

Plant Reproduction Asexual Reproduction of Seed Plants

A.Vegetative Reproduction - asexual production of new plants 1. Stolons - horizontal stems 2. Plantlets - ‘little’ plants 3. Underground roots Grass - Stolons Spider Plant - Plantlets Aspen Tree – Underground Roots Largest Organism! 106 acres!

B. Plant Propagation - humans using different ways to reproduce plants 1. Cuttings - cut a stem off of and put it into soil

B. Plant Propagation - humans using different ways to reproduce plants 2. Grafting and Budding - plants are attached to other plants in order to grow a. scion - the part of the plant being grafted; stems in grafting, buds in budding b. stock - plant to which a scion is attached Orange and Grapefruit Tree Grafted Cactus Blooming

Pooktre! Tree Art!

C. Agriculture 1. Humans have been able to cultivate plants as food for centuries. 2. Most people in the world depend on just wheat, rice, and corn for the bulk of their food supply. Wheat Corn Rice