chapter 38 angiosperm reproduction and biotechnology
TRANSCRIPT
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