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Chapter 30

STUDY
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integuments
layer of sporophyte tissue that envelop and protect the megasporangium; one surrounds gymnosperm megaspores; two around angiosperms
ovule
the whole structure of-megasporangium, megaspore, and their integument(s); inside each a female gametophyte develops from a megaspore and produces one or more egg cells
pollen grains
what microspores develop into; contain the male gametophytes of seed plants; protected by a tough coat containing the polymer sporopollenin; can be carried away from their parent plant by the wind or hitchhiking on other moving organisms
pollination
the transfer of pollen to the part of a seed plant containing the ovules
pollen tube
when a pollen grain germinates (grows); discharges two sperm into the female gametophyte within the ovule
seed
what a whole ovule develops into; consists of the embryo, along with a food supply, packaged within a protective coat derived from the integument(s); enables plants bearing them to better resist the harsh enviroments and to disperse offspring more widely
conifers
part of gymnosperms that are cone-bearing plants such as pines, firs, and redwoods
progymnosperms
extinct seedless vascular plants that may be ancestral to seed plants
flower
an angiosperm structure specialized for sexual reproduction; insects and other animals transfer pollen from one to the female sex organs of another (makes pollination more directed); a specialized shoot that can have up to four rings of modified leaves called floral organs
floral organs
sepals, petals, stamens, and carpels
sepals
the organs that is at the base of the flower which are usually green and enclose the flower before it opens; sterile floral organ
petals
above the sepal; brightly colored in most flowers and aid in attracting pollinators; wind-polinating flowers generally lack colorful parts; sterile floral organ
whorl
found in petal where the fertile sporophylls, floral organs can produce spores; of floral organs- attached to receptacle
stamens
one of the whorls of sporophylls; the microphylls that produce microspores that give rise to pollen grains containing male gametophytes; consists of filaments and anthers
filaments
a stalk that makes up stamens
anther
a terminal sac that makesup stamens where pollen in produced
carpels
one of the whorls of sporophylls; megasporophylls which make megaspores and their products- female gametophytes; many angiosperms have flowers with mulitples of these; some have a single one (garden peas)
stigma
foudn at the tip of a carpel; recieves pollen
style
the stalk of the flower's carpel, with the ovary at the base and the stigma at the top
ovary
found at the base of the carpel which contains one or more ovules; if fertilizes, it develops into a seed
receptacle
part of the stem where whorls are attached to
pistil
a singe carpel or a group of fused carpels
fruit
typically consists of a mature ovary, although it can include other flower parts as well; the product when the ovary thickens; protect dormant seeds and aid in their dispersal; begins to develop after pollination triggers hormonal changes that cause the ovary to grow; if a flower is not pollinated, it usually does not develop ; can be either fleshy or dry; can be categorized according to whether they develop from a single ovary, from mulitple, or even more than one flower
pericarp
what the wall of the ovary develops into which is a thickened wall of the fruit; layers can be soft or dry
generative cell
part of a pollen grain which has two haploid cells; divides into two sperm
tube cell
produces a pollen tube
embryo sac
a female gametophyte that is found within an ovule; consists of only a few cells, one is the egg
cross-pollination
a mechanism used by self-pollinating flowers; in angiosperms, it is the tranfer of pollen from an anther of a flower on one plant of the same species; enhances genetic variation; may cause stamens and carpels to mature at different times
micropyle
a pore in the integuments of the ovule; pollen tube penetrates through it; discharges two sperm cells into female gametophyte (embryo sac); one fertilizes the egg, forming a diploid zygote; the other fuses with the two nuclei in the large central cell of the female gametophyte
double fertilization
type of angiosperm unique to angiosperms; occurs from two sperm cells: one fertilizes the egg, forming a diploid zygote; the other fuses with the two nuclei in the large central cell of the female gametophyte; function- synchronizes the development of food storage in the seed with the development of the embryo; also occurrs in gymnosperms
cotyledons
a seed leaf of an angiosperm embryo; some species have one while other have two
endosperm
tissue rich in starch and other food reserves; develops from the nucleus of the central cell of the female gametophyte repeatedly dividing
monocots
species with one cotyledon; typically have parallel leaf veins; examples include orchids, palms, and grain crops
dicots
species wiht two cotyledon; veins of most have a netlike pattern; examples include roses, peas, sunflowers, and maples
eudicots
the vast majority of species traditionally called dicots; translated as "true" dicots
basal angiosperms
one of the three lineages from dicots; appear to include the flowering plants belonging to the oldest lineages
magnoliids
another lineage from dicots that evolved after basal angiosperms