MIDTERM EXAM #2 Flashcards
what is the definition of plant reproduction?
the formation of new individuals or the production of new members of a population from existing members. many also involve growth processes that result in the persistence of an individual, although in a new location.
what is the definition of plant asexual reproduction?
reproduction where a plant replicates itself without the involvement of meiosis or fertilization.
asexual reproduction is a product of ______ which is cell division producing __ daughter cells each with the (same or different) number of chromosomes as the parental cell.
mitosis.
2
the same
true or false: asexual reproduction in plants is very common
true. it often involves normal growth and ecological processes that result in the production of an independent plant
what are examples of asexual reproduction in plants?
-stoloniferous
-adventitious
-totipotency
-production of plantlets
what is stoloniferous/rhizomatous/spreading growth?
laterally growing stems that produce roots at nodes and may become independent plants over time
what are examples of stoloniferous growth?
-caespitose grasses
-plantlets (pups or suckers)
-tubers
-corms
-bulbs
what are plantlets?
buds at the base of a plant that develop comparitvely quickly into an entire plant. very common in agaves. grow from rhizomes or basal buds.
what are tubers?
typically a thickened rhizome or stolon (stem tissue). (potatoes are an example of)
tubers are a ______ ______ that seems to allow a plant to survive a period of _____ environmental conditions in a semi-protected state.
storage organ
harsh
what are corms?
short, vertical and thickened underground stem (stem tissue). storage tissue that may produce a new individual
what are bulbs?
underground vertical shoot with overlapping leaves modified for energy storage. (unions and garlic).
what is caespitose grass?
grass that grows in dense tufts and will produce new stems or tillers from buds at the base of the plant. commonly called bunchgrasses.
what is a tiller?
individual leaf and stem structure
caespitose grasses form a _____-_____ structure and successive ____ of _____ form outwards and create ____ as old tillers die. this type of movement is called _________
ring-like
rings of tillers
rings
spreading
what is king clone?
a ring formation of creosote bush that is ~21 meters in diameter at max. point
what is adventitious asexual reproduction and what is an example of this?
appearing in an abnormal or unusual position.
ex) formation of roots on non-root organs
what is totipotency (asexual reproduction)?
the ability of a single cell to produce specialized cells of many types given the correct circumstances. a cell is able to re-differentiate into an entirely different cell or organ type
the production of _______ from flowers (asexually) is common in agaves. Agaves are ______: they flower once and then die. the _____ may form in axis of floral bracts (modified leaves).
plantlets.
monocarpic.
plantlets
true or false: plantlets usually die when the mother plant dies
false; plantlets usually persist after mother plant dies and may establish as an independent plant.
what are the two organs related to plant sexual reproduction?
fruits and flowers
is meiosis sexual or asexual reproduction? what do you start and end with?
sexual reproduction. 1 parental cell (2n) –> 4 daughter cells (1n) (gametes).
what are plant gametes called?
pollen and egg cell (1n)
a gamete producing plant is called a _______ and a spore producing plant is called a _________
gametophyte (1n)
sporophyte (2n)
sporophytic meiosis produces what?
4 daughter cells
draw out or explain the cycle of the alternation of generations in plants
sporophyte (2n) –> meiosis –> spores (1n) –> gametophyte (1n) –> mitosis–> gametes (1n) –> fertilization –> zygote (2n) –> mitosis –> sporophyte (2n)
the transfer or movement of pollen grains is called ________
pollination. pollination does not equal fertilization
what are common examples of pollinators?
birds, insects, bats, and other animals. wind and water may also affect pollination
what two structures make up a stamen? what is a stamen associated with?
anther and filament.
associated with the microgametophyte
the ______ contain spores/pollen grains. when mature, the _____open up and release spores which travel to the top of the ______
anther
anthers
stigma
what is a microgametophyte?
a small gamete (pollen grain) producing plant with only 3 cells: a tube nucleus cell and two smaller sperm cells.
the microgametophyte grows down through the _______ and is a _____ _____
style
pollen tube or sperm delivery structure
what is a megagametophyte?
gamete producing plant structure that divides 3 times to create 8 nuclei. also known as an embryo sac.
describe the composition of the 8 nuclei that’re created in a megagametophyte
-1 gamete (egg cell)
-2 cells that’re close to the egg called synergids
-3 cells opposite from the egg called antipodal cells
-1 cell in the center called the center cell that has 2 nuclei that’re called polar nuclei.
as the _____ _____ goes through the style, it will reach and enter the __________ and will release its sperm nuclei.
pollen tube
megagametophyte
once the sperm has been released, one sperm cell will go the ____ ____ and fertilize it to create an _______ and the other sperm cell will fertilize the 2 polar nuclei in the _______ _____. this process is called what?
egg cell (gamete)
embryo
center cell
double fertilization
double fertilization results in the production of a nutritive tissue called _______ within the seed, which facilitates the production of a _____ ____ after double fertilization
endosperm
mature ovule
what is an ovule?
maternal tissue and megagametophyte that eventually form a seed. seeds are encased within the ovary wall, which will develop into a fruit.
a fruit is a _______ _______
mature ovary. flowers produce fruits that enclose seeds
true or false: the existence of seeds and fruits are one of the primary reasons why flowering plants dominate over non flowering plants.
true
what are the main roles of fruits?
-protect seeds
-effect seed dispersal
-provide nutrients for seeds, embryo, and seedlings
how are fruits classified?
dry vs. fleshy
dry: moisture content is below ~20% when seeds are mature
fleshy: high moisture content
dry fruits can also be classified into two categories:
indehiscent: doesn’t open at maturity
dehiscent: opens at maturity to release it’s contents
what are the 8 types of dry fruits?
-schizocarp
-caryopsis
-achene
-nut
-silique
-capsule
-legume
-follicle
what are the 3 types of fleshy fruits?
-berry
-pepo
-drupe
discuss all of the ways in which plants can move
pollen grains/spores can move via wind, animals, humans, and gravity.
plant bodies/vegetative structures can move via stoloniferous growth or being attached to animals
what is interspecific hybridization?
occurs when two different plant species are interbred to form a new species. is a relatively common process in plants and may be associated with polyploidization.
why is interspecific hybridization possible with plants in the wild?
it is possible with wild plants because the stigma is not a perfect barrier to “foreign” pollen and frequently pollen flows in the wind and can land anywhere.
why is hybridization considered to be possibly beneficial for plants?
it allows the hybrid plant to survive in a new type of environment, one intermediate between the two parental plants’ environments. most of the time the two parent plants can’t survive in the new environment
what is polyploidization?
polyploidization is an error in cell division that results in an increase in chromosome number. (polyploids: species with additional chromosome sets)
polyploidization in diploids:
-chromosomes (do or do not) pair consistently in diploid hybrid
-spores (are or are not) chromosomally balanced and (do or do not) develop normally
-do not
-are not
-do not
polyploidization in tetraploids (4n):
-chromosomes (do or do not) pair consistently in tetraploid hybrids
-spores (are or are not) chromosomally balanced and (do or do not) develop normally.
-do
-are
-do
tetraploid x diploid = ?
hexaploid (6n)
what is apomixis?
asexually produced seeds that are usually derived from diploid cells surrounding the embryo sac. (the egg cell doesn’t produce an embryo). common in the fam. Poaceae
during apomixis, does meiosis occur?
no, meiosis doesn’t occurs. The egg is diploid (2n), meaning that the seeds are genetically the same as the parental plant.
what is apomixis frequently associated with?
polyploidization
apomixis may be ___________, meaning that regular sexually produced seeds may also be produced
facultative