Chapter 29 13-03-03 1:59 PM
Sporophyte: diploid spore producing body of a plant. Produced through
fertilization in organism that under go alternation of generations (diploid
sporophyte -> haploid spores and back).
Gameteophyte: Individual of the haploid generation. Produce haploid
gametes by mitosis, male gameteophytes produce sperm and female
gameteophytes produce eggs.
Alternation of generations: diploid spore-producing generation and a
haploid gamete-producing generation.
Monoecious: having both male flowers (which contain only stamens) and
female flowers (which contain only stamens).
Dioecious: having male flowers and female flowers on different plants of
the same species.
Ovary: the base of the carpel that produces one or more ovules.
Ovule: where the egg develops and fertilization occurs
Polar nuclei: the two haploid cells that for the endosperm mother cell. The
endosperm will provide nutrients to the embryo after fertilization.
Self-Incompatability: in plants, the inability of a plant’s pollen to fertilize
ovules of the same plant.
Double fertilization: when the two sperm cells from the pollen gain
(generative cell) travel down the formed pollen tube and fertilize both the
egg and the endosperm.
Endosperm: the polar nuclei cell that is formed, once fertilized, provides
nutrients to the embryo.
Pericarp: the fruit wall.
Cotyledon: a leaf of a seed plant embryo; also known as a seed leaf.
Dormancy: a period in the lifecycle in which biological activity is suspended.
Vegetative Reproduction: asexual reproduction in plants by which new
individuals arise without seeds or spores; fragmentation or plant cuttings.
Totipotent: the ability to develop into any type of cells.
Callus: an undifferentiated tissue that develops on or around a cut plant
surface or in tissue culture.
29.1 Overview of Flowering Plant Reproduction ⋅ an angiosperm zygote develops into an embryo enclosed in a seed
• embryo is in sporophyte generation– diploid, spore-producing
⋅ male stamen includes the filament and the anther.
• Diploid microspore in the anther –> undergoes meiosis
• Four microspores are produced and each one develops
29.3 Pollination, Fertilization, and Germination
a. Pollination requires compatible pollen and female tissues.
• Pollen and stigma must be genetically different (promoting genetic
variation) • If they are from the same plant, fertilization will not occur b/c they
are chemically incompatible
• If for whatever reason, they do pollinate, the growth of the pollen
tube will be altered
o May not be long enough
o Fruit may fall off
• The plant can tell if they are genetically incompatible if both the
pollen and stigma have the “self-allele” – “S” allele
• Cross pollination is favorable.
b. Double fertilization results in the formation of embryos and endosperm
• Double fertilization is only observed in flowering plants
• 1 sperm fuses with the egg= diploid (2n) zygote
• 1 sperm fuses with the central cell=triploid (3n) nucleus
o 3n nucleus becomes the endosperm
o endosperm offers nourishment for the embryo
o it is inside the seeds of flowering plants
c. After fertilization, ovaries develop into fruits that protect seeds and aid
• Fruit is a ripened/mature ovary
• Parthenocarpy- plants produce fruit w/out fertilization and therefore
o Fruit ripening is stimulated by hormones released by the
sperm cells and the seed after fertilization
o It can be stimulate (by scientists) to produce seedless fruit.
• Fruit is classified as either fleshy or dry
• Simple fruit: cherries, peaches; forms from one ovary, and one
• Aggregate Friut: form from single flowers with multiple carpels