Chapter 38

Angiosperm Reproduction and Biotechnology

AngiospermsAnthophytaMore specialized xylem evolved.Tracheids seen in gymnosperms gave rise

to vessel elementsXylem is reinforced by second cell wall, the

fiber (also seen in conifers)Flower is the reproductive structureCoevolution is seen between flowers and

animals

Sporophyte/GametophytesThe life cycle of the angiosperms shows

very reduced gametophyte generations.What is the male gametophyte?What is the female gametophyte?What is pollination?Bringing pollen to the stigma.How does self-incompatibility work?

Ability of a plant to reject its own pollen and sometimes the pollen of closely related individuals

Double Fertilization

The pollen tube grows following pollination and leads to double fertilization.

What is fertilized?Sperm + egg = zygote (2n)Sperm + 2 polar nuclei = endosperm (3n)

Seed DevelopmentEndosperm develops before embryoEndosperm provides food for developing

embryoEmbryo reaches a certain size and then

enters dormancy until germination.

Development of a eudicot embryo

Germination

How can seed dormancy be advantageous to a plant?

Helps with dispersal Doesn’t leave dormancy until conditions are

good What are some conditions for breaking

dormancy?1. Desert – Only after good rainfall2. Chaparral – fire3. Others – coats weakened by digestive enzymes

as they pass through animal’s digestive tract

Germination depends upon….Imbibition-uptake of water due to the low

water potential of the dry seedHormone release

Radicle emerges from seedShoot tip breaks through the soil.Until this point how has the embryo

received nutrients?Endosperm(food)and radicle (water).

The Fruit What is a fruit? After fertilization the ovary becomes the

fruit. It protects the seeds. Name three modifications that different

fruits have for seed dispersal.1. Sweeten and turns colorful when ripe2. Have burrs that can stick to animal’s fur3. Feathery like dandelions for wind

dispersal of seeds

Review the Evolution of Alternation of Generations in Plants