sporophytes
How long is the life cycle of a pine?
Pine trees prefer acidic or sandy soils. However, they are able to grow in environments that are difficult for other trees, such as rocky sites, limestone and habitats at high altitudes. Pine trees can grow up to 150 feet and have a lifespan of
over 100 years
.
How long have conifers been around?
Overview. Conifers have a long and noble history. They have been around
since the days of the dinosaurs
—in fact, 150 million years ago they were the most prevalent plants in the landscape, since flowering plants had not yet come into their own.
How do conifers evolve?
Modern groups of conifers
emerged from the Voltziales during the Late Permian through Jurassic
. Conifers underwent a major decline in the Late Cretaceous corresponding to the explosive adaptive radiation of flowering plants.
How does conifer fertilization occur?
All conifers are
pollinated by wind
. Pollen may be produced in enormous quantities, particularly by species of true pine (Pinus), which can blanket the surface of nearby lakes and ponds with a yellow scum of pollen (the pollen can cause allergies in humans).
How does a conifer reproduce?
Conifers reproduce
using their cones
. Some cones are male and some are female. The male cones release pollen. This pollen is carried by the wind.
How many generations can you find in a conifer seed?
Conifer seeds are very complex little structures, containing cells from
three generations
of the tree. The nutritive tissues inside the seed are actually the haploid body cells of the female gametophyte.
How long do longleaf pines live?
The lifespan of a longleaf pine spans several centuries. These slow-growing trees live for
over 300 years
, and they may take up to half that time to reach their full size.
Why are seeds of conifers called naked seeds?
In gymnosperms (plants with “naked seeds”—such as conifers, cycads, and ginkgo),
the ovules are not enclosed in an ovary but lie exposed on leaflike structures, the megasporophylls
.
Are all conifers woody?
All living conifers are woody plants
, the great majority being trees with just a few being shrubs. Typical examples of conifers include cedars, cypresses, firs, junipers, pines, redwoods, spruces, and yews.
Do all conifers have needles?
Conifers include pine, spruce, fir, cedars, larch (also known as tamarack), and many more. A conifer is a cone-bearing tree which almost always has modified leaves known as needles, and is typically evergreen.
All true conifers have needles, but they’re a bit different in nature
.
Do coniferous trees lose their leaves?
Most (not all) conifers keep their leaves year round
, while many broadleaved trees (including all of those that grow in the Methow) shed their leaves in the fall and grow new ones in the spring—an approach to life that seems wasteful, if not downright profligate, on its face.
When did seeds first appear?
Seed plants appeared
about one million years ago
, during the Carboniferous period. Two major innovations were seeds and pollen. Seeds protect the embryo from desiccation and provide it with a store of nutrients to support the early growth of the sporophyte.
What is the scientific name of conifer?
Pinophyta
Where do conifers originate from?
The fossil record shows that conifers originated in
Europe and North America
during the Middle Pennsylvanian approximately 310 million years ago, subsequently diversifying and radiating across the global landscape.
How does sperm reach egg in conifers?
Conifers have sperm that do not have flagella, but instead are conveyed to the egg
via a pollen tube
. It is important to note that the seeds of gymnosperms are not enclosed in their final state upon the cone.
Where is the pollen of a conifer?
Conifers often produce pollen cones
lower in the tree
than the seed cones. The wind is more likely to blow the pollen to another tree than up to the seed cones above on the same tree. This is particularly true of the firs, which produce seed cones near the treetop. Their pollen cones are typically lower in the tree.
How are seeds fertilized?
The launch of seed development in flowering plants (angiosperms) is initiated by the process of double fertilization: two male gametes (sperm cells) fuse with two female gametes (egg and central cell) to form the precursor cells of the two major seed components, the embryo and endosperm, respectively.
Are conifers asexual?
The two main ways that flowering plants and conifers reproduce are sexual reproduction by means of seeds and
asexual reproduction by means of separating and rooting part of a plant, cloning the mother plant
.
Can you grow a conifer from seed?
Though individual species do grow at differing rates,
a young conifer will generally be ready for its permanent growing spot two years after its seed was sown
. Once again, it’s important to disturb the root ball as little as possible in the transplanting process.
How does the life cycle of conifers differ from flowering plants?
They undergo double fertilization to produce a triploid endosperm. The seed of the flowering plants is covered by a fruit. On the other hand,
conifers produce unisexual cones as the reproductive structures. They do not undergo double fertilization and the seed of the conifer is naked
.
Why fertilization of conifer plants are taking more than one year?
Answer: Fertilization and seed development is a long process in pine trees:
it may take up to two years after pollination
. The seed that is formed contains three generations of tissues: the seed coat that originates from the sporophyte tissue, the gametophyte that will provide nutrients, and the embryo itself.
What plant fertilizes an egg?
Fertilization occurs when
pollen grains
(male gametophytes) are carried by the wind to the open end of an ovule, which contains the eggs, or female gametophyte. There, the pollen grain develops an outgrowth called a pollen tube, which eventually penetrates to the egg cell within one of the archegonia.
Do conifers have fruit?
A conifer cone (in formal botanical usage: strobilus, plural strobili) is a seed-bearing organ on gymnosperm plants.
It is a type of fruit, usually woody, ovoid to globular, including scales and bracts arranged around a central axis, especially in conifers and cycads
.
What’s the oldest tree in the world?
The Great Basin Bristlecone Pine (Pinus Longaeva)
has been deemed the oldest tree in existence, reaching an age of over 5,000 years old. The Bristlecone pines’ success in living a long life can be attributed to the harsh conditions it lives in.
Which pine has the longest needles?
Longleaf pine (pinus palustris)
has the longest pine needles measuring 18” (45 cm) long.
How long do yellow pines live?
Longleaf pine takes 100 to 150 years to become full size and may live to be
500 years old
. When young, they grow a long taproot, which usually is 2–3 metres (61⁄2–10 feet) long; by maturity, they have a wide spreading lateral root system with several deep ‘sinker’ roots.
