Open main menu
Home
Random
Recent changes
Special pages
Community portal
Preferences
About Wikipedia
Disclaimers
Incubator escapee wiki
Search
User menu
Talk
Dark mode
Contributions
Create account
Log in
Editing
Conifer
(section)
Warning:
You are not logged in. Your IP address will be publicly visible if you make any edits. If you
log in
or
create an account
, your edits will be attributed to your username, along with other benefits.
Anti-spam check. Do
not
fill this in!
===Reproduction=== {{Main|Conifer cone}} Most conifers are [[Plant reproductive morphology#Terminology|monoecious]], but some are [[Plant reproductive morphology#Terminology|subdioecious]] or [[Plant reproductive morphology#Terminology|dioecious]]; all are [[Anemophily|wind-pollinated]]. Conifer seeds develop inside a protective cone called a [[strobilus]]. The cones take from four months to three years to reach maturity, and vary in size from {{Convert|2 to 600|mm|frac=8}} long. In [[Pinaceae]], [[Araucariaceae]], [[Sciadopityaceae]] and most [[Cupressaceae]], the cones are [[wood]]y, and when mature the scales usually spread open allowing the seeds to fall out and be dispersed by the [[wind]]. In some (e.g. [[fir]]s and [[Cedrus|cedar]]s), the cones disintegrate to release the seeds, and in others (e.g. the [[pine]]s that produce [[pine nut]]s) the nut-like seeds are dispersed by [[bird]]s (mainly [[Nutcracker (bird)|nutcracker]]s, and [[jay]]s), which break up the specially adapted softer cones. Ripe cones may remain on the plant for a varied amount of time before falling to the ground; in some fire-adapted pines, the seeds may be stored in closed cones for up to 60β80 years, being released only when a fire kills the parent tree. In the families [[Podocarpaceae]], [[Cephalotaxaceae]], [[Taxaceae]], and one [[Cupressaceae]] genus (''[[Juniper]]us''), the scales are soft, fleshy, sweet, and brightly colored, and are eaten by fruit-eating birds, which then pass the seeds in their droppings. These fleshy scales are (except in ''Juniperus'') known as [[aril]]s. In some of these conifers (e.g. most Podocarpaceae), the cone consists of several fused scales, while in others (e.g. Taxaceae), the cone is reduced to just one seed scale or (e.g. Cephalotaxaceae) the several scales of a cone develop into individual arils, giving the appearance of a cluster of berries. The male cones have structures called [[sporangium|microsporangia]] that produce yellowish pollen through meiosis. Pollen is released and carried by the wind to female cones. Pollen grains from living pinophyte species produce pollen tubes, much like those of angiosperms. The [[gymnosperm]] male gametophytes (pollen grains) are carried by wind to a female cone and are drawn into a tiny opening on the ovule called the [[wikt:micropyle|micropyle]]. It is within the ovule that pollen-germination occurs. From here, a pollen tube seeks out the female gametophyte, which contains archegonia each with an egg, and if successful, fertilization occurs. The resulting [[zygote]] develops into an [[embryo]], which along with the female gametophyte (nutritional material for the growing embryo) and its surrounding integument, becomes a [[seed]]. Eventually, the seed may fall to the ground and, if conditions permit, grow into a new plant. In [[forestry]], the terminology of [[flowering plant]]s has commonly though inaccurately been applied to cone-bearing trees as well. The male cone and unfertilized female cone are called ''male flower'' and ''female flower'', respectively. After fertilization, the female cone is termed ''fruit'', which undergoes ''ripening'' (maturation). It was found recently that the [[pollen]] of conifers transfers the [[mitochondria]]l [[organelle]]s to the [[embryo]],{{citation needed|date=June 2021}} a sort of [[meiosis|meiotic]] drive that perhaps explains why ''[[Pinus]]'' and other conifers are so productive, and perhaps also has bearing on observed sex-ratio bias.{{citation needed|date=August 2021}} <gallery class="center"> File:Abies lasiocarpa 6972.JPG|Pinaceae: unopened female cones of [[Abies lasiocarpa|subalpine fir]] (''Abies lasiocarpa'') Taxus baccata MHNT.jpg|Taxaceae: the fleshy aril that surrounds each seed in the [[Taxus baccata|European yew]] (''Taxus baccata'') is a highly modified seed cone scale Japanese Larch pollen cone, Cardiff, Wales.jpg|Pinaceae: pollen cone of a [[Japanese larch]] (''Larix kaempferi'') </gallery>
Edit summary
(Briefly describe your changes)
By publishing changes, you agree to the
Terms of Use
, and you irrevocably agree to release your contribution under the
CC BY-SA 4.0 License
and the
GFDL
. You agree that a hyperlink or URL is sufficient attribution under the Creative Commons license.
Cancel
Editing help
(opens in new window)