Chapter 38 Flashcards
what helps angiosperms reproduce sexually with distant members of their own species?
insects
how do angiosperms lure insects?
-with nectar; both plant and pollinator benefit
true or false:
angiosperms can reproduce sexually and asexually
true
what are plant lifecycles characterized by?
the alternation between a multicellular haploid (n) and a multicellular diploid (2n) generation
diploid sporophytes (2n) produce_____ by ______; these grow into ______ gametophytes
spores (n) by meiosis ; these grow into haploid gametophytes
gametophytes produce ____ gametes by ____
- haploid
- mitosis
fertilization of gametes produces…
a sporphyte
what are the four floral organs of the flowers?
- sepals, petals, stamens, and carpels
which of the four organs of the flowers are sterile and which are reproductive?
- stamens and carpels are reproductive
2. sepals and petals are sterile
what are the reproductive shoots of the angiosperm sporphytle
flowers
anther
- this tops the stamen and has pollen sacs that produce pollen
what makes up the carpel
a long style and a stigma at the end on which pollen may land
what is at the base of the style?
an ovary containing one or more ovules
pistil
a single carpel or group of fused carpels
complete flowers
contain all four floral organs
incomplete flowers
lack one or more floral organs
inflorescences
clusters of flowers
where does pollen develop?
from microspores within the microsporangia, or pollen sacs of anthers
each microspore undergoes mitosis to produce what two cells?
- the generative cell
2. the tube cell
a pollen grain contains what?
- the two-celled male gametophyte
2. the spore wall
pollen grain produces what that grows down into the ovary and discharges two sperm cells near the embryo sac?
pollen tube
where does the embryo sac develop?
within the ovule
what is there to know about what happens in the ovule?
- two integuments surround a megasporangium
- one cell in the megasporangium undergoes meiosis, producing four megaspores, only one of which survive
- the megaspore divides, producing a large cell with eight nuclei
- the cell is partitioned into a multicellular female gametophyte, the embryo sac
megasporangium
A plant structure in which megaspores are formed
what are the different ways of pollination
by wind, water, or animals
coevolution
the evolution of interacting species in response to change in each other
double fertilization
discharge of two sperm from the pollen tube into the embryo sac
-one sperm fertilizes the egg, and the other combines with the polar nuclei, giving rise to the food storing endosperm
what happens after double fertilization
each ovule develops into a seed
-the ovary develops into a fruit enclosing the seed
does endosperm development usually precede or follow embryo development
precede
the food reserves of the endosperm can do what two things
- In most monocots and some eudicots, endosperm stores nutrients that can be used by the seedling
- In other eudicots, the food reserves of the endosperm are exported to the cotyledon
what happens in the first mitotic division of the zygote?
-The first mitotic division of the zygote splits the fertilized egg into a basal cell and a terminal cell
• The basal cell produces a multicellular suspensor, which anchors the embryo to the parent plant
• The terminal cell gives rise to most of the embryo
• The cotyledons form and the embryo elongates
seed coat
a hard and protective covering that the embryo and its food supply are enclosed by
-then the seed enters a state of dormancy
hypocotyl
the embryonic axis below the cotyledons
radicle
embryonic root
epicotyl
above the cotyledons
cotyledons
seed leaves
*such as the two parts of beans or the two parts of peanuts
what does seed dormancy increase the chances of?
germination will occur at a time and place most advantageous to the seedling
-breaking of seed dormancy requires environmental cues such as temperature or lighting changes
imbibition
the uptake of water due to low water potential of the dry seed
-germination depends on imbibition
what is the seedling development (or germination) process?
- the embryonic root emerges first
- next, the shoot tip breaks through the soil surface
- (in many eudicots) a hook forms in the hypocotyl, and growth pushes the hook above ground
- Light causes the hook to straighten and pull the cotyledons and shoot tip up
a fruit develops from what?
from the ovary
-it protects the enclosed seeds and aids in seed dispersal by wind or animals
what classifies a fruit as dry or fleshy
A fruit may be classified as dry, if the ovary dries out at maturity, or fleshy, if the ovary becomes thick, soft, and sweet at maturity
what are the three classifications for plants based on their developments
- simple, a single or several fused carpels
- aggregate- a single flower with multiple separate carpels
- multiple, a group of flowers called an inflorescence
why do plants prefer sexual reproduction rather than asexual
-sexual reproduction produced genetically different offspring which allows for more diversity and less occurrence of “bad traits”
fragmentation
separation of a parent plant into parts that develop into whole plants, is a very common type of asexual reproduction
apomixis
the sexual production of seeds from a diploid cell
vegetative reproduction
another term for asexual reproduction
dioecious
species that have staminate and carpellate flowers on separate plants
**others have stamen and carpels that mature at different times or are arranged to prevent selfing
self-incompatibility
a plants ability to reject its own pollen
adventitious roots
roots which develop from stems.
callus
a mass of dividing undifferentiated cells that forms where a stem is cut and produces adventitious roots
transgenic plants
genetically modified to express a gene from another organism
protoplast fusion
used to create hybrid plants by fusing protoplasts, plant cells with their cell walls removed
what are the two meanings of plant biotechnology
– In a general sense, it refers to innovations in the use of plants to make useful products
– In a specific sense, it refers to use of GM organisms in agriculture and industry
biofuels
-made by the fermentation and distillation of plant materials such as cellulose
• Biofuels can be produced by rapidly growing crops such as switchgrass and poplar
• Biofuels would reduce the net emission of CO2, a greenhouse gas
what is the concern of GMO’s
-One concern is that genetic engineering may
transfer allergens from a gene source to a plant used for food
-Many ecologists are concerned that the growing of GM crops might have unforeseen effects on nontarget organisms
-Perhaps the most serious concern is the possibility of introduced genes escaping into related weeds through crop-to-weed hybridization; This could result in “superweeds” that would be
resistant to many herbicide
what does the macronutrients magnesium, calcium, and sulfer do in plants?
magnesium- participates in metabolic processes of other nutrients uptake, and Promotes proper plant cell elongation.
sulfur- used in the formation of amino acids, proteins, and oils. It is necessary for chlorophyll formation
