Chapter 23 Flashcards
Angiosperm in Greek
” vessel”“seed”, flowering plant
The “vessel” is the
carpel
carpel
inrolled leaf with seeds along its margins
Many flowers have
pistils
A seed develops from an _____ in a ________ and is part of an _____ that becomes a _____
Ovule, carpel, ovary, fruit
All angiosperms are presently considered to be in the Phylum
Magnoliophyta
Phylum Magnoliophyta is divided into two large classes
Magnoliopsida (dicots)
Liliopsida (monocots)
pteridosperms
seed ferns
Saprophyte
their nutrients come from the absorption of dead organic material
Angiosperms are heterosporous, meaning
they produce two kinds of spores
At maturity, the male gametophyte consists of
a pollen grain with three nuclei
while the flower is developing in the bud, a ________ cell differentiates from all the other cells in the ovule
megasporocyte
This megasporocyte undergoes meiosis, producing 4 haploid
megaspores
Soon after the megaspores are produced,
three of the megaspores degenerate and disappear, but the nucleus of the fourth undergoes mitosis and the cell enlarges
By the end of the division process, _ haploid nuclei are produced
8
Integuments
layers that later become the seed coat
As the integuments develop, they leave a pore called the
micropyle
female gamete
egg
male gamete
sperm
synergids
assist in guiding a pollen tube to the egg
pollen tube
method of transportation for the pollen to the egg
Antipodals
3 remaining cells at the other end that help with nutrient absorption
A process that leads to the formation of the male gametophyte takes place in the
anther
As an anther develops, four patches of tissue
differentiate from the main mass of cells
these differentiated patches of tissue contain many
microsporocyte cells
Each microsporocyte cell undergoes meiosis, producing a
quartet, or tetrad of microspores
The following 3 changes are most important
- the microspore divides once by mitosis to produce two cells. one of the cells (the generative cell) is small and is formed inside the larger cell (the tube cell)
- The membrane of each quartet of microspores separate from one another
- a two layered wall, whose outer layer is often finely sculptured, develops around each microspore
When the 3 most important changes are complete, the microspores have become
pollen grains
exine
the outer layer of the pollen grain wall, and contains chemicals
apertures
Many pollen grains have 3 pore like apertures in the wall, the number of apertures may range from one to many
Pollination
the transfer of pollen grains from an anther to a stigma
Fertilization
involves the union of the egg and sperm
double fertilization
one sperm migrates from the synergid to the egg, the sperm cell nucleus then unites with the egg nucleus, forming a zygote.
The other sperm cell also migrates from the synergid to the central cell, and upon reaching the central cell, they unite and form a triploid endosperm nucleus
endosperm
nutritive triploid tissue that may have hundreds of thousands of nuclei
apomictically
some embryos can develop this way, that is, without the fusion of gametes
Parthenocarpic
fruits that develop from ovaries having unfertilized eggs
radial symmetry
flower can be divided into two equal halves along more than one lengthwise plane
inferior ovary
when the ovary is embedded in the receptacle and other parts
epigynous
inferior ovary with flower parts attached at the top
superior ovary
produced on top of the receptacle with the other flower parts around its base
hypogonous
such flower parts that attach around the base of a superior ovary
Some flowers appear to have ovaries in an ___________ position with _________ flower parts
intermediate, perigynous
bilateral symmetry
capable of being divided into two symmetrical halves only by a single lengthwise plane passing through the axis
Complete flower
has a calyx, corolla, stamens, pistil
Missing flower
missing one or more of the elements that make a complete flower. (calyx, corolla, stamens, pistil)
Perfect
both stamens and pistil are present
Imperfect (unisexual)
has either stamens or a pistil but not both
Monoecious
both imperfect flower sexes occur on the same plant
dioecious
the imperfect flower sexes occur on different plants in the same species. (ginkgo)
All pollinators are attracted to
different individualized characteristics of plants
Pollinia (singular: pollinium)
sacs that the pollen grains of most orchids are produced in. typically have sticky pads at their bases
