What is an ovulate cone?
The female cone (megastrobilus, seed cone, or ovulate cone) contains ovules which, when fertilized by pollen, become seeds. The female cone structure varies more markedly between the different conifer families, and is often crucial for the identification of many species of conifers.
Do ovulate cones produce pollen?
One type of cone is the small pollen cone, which produces microspores that subsequently develop into pollen grains. The other type of cones, the larger “ovulate” cones, make megaspores that develop into female gametophytes called ovules. This is the cone that produces pollen.
How do ovulate cones form?
Ovulate Cone The megasporocyte divides by meiosis to produce the four haploid megaspores, three of which degenerate. The nucleus of the surviving megaspore divides repeatedly by mitosis and a multicellular megagametophyte composed of thousands of haploid cells is produced within the enlarged megaspore.
How are cones pollinated?
The male cones release their pollen, which is carried around the air by blowing wind, and hopefully to another female pine cone on a different pine tree. If the pollen reaches a female pine cone, this process is called pollination.
What happens after a female cone is fertilized?
Over a two to three year period after fertilization, the woody female pine cone develops. In some species, the cones open at maturity and the seeds are released. In others the cones remain closed for several years until opened by rotting, by food-seeking animals, or by fire.
How do cone bearing plants reproduce?
Cone-bearing plants have two types of cones: female cones and male cones. Reproduction begins when one of the pollen grains from inside a pollen sac on the male cone floats through the air to the scale of a female cone. A pollen tube then grows from the pollen grain toward the female ovule.
How do cone-bearing plants reproduce?
How do the eggs from a female cone and the pollen from a male cone come together?
When the egg cells are ready, the pollen grain enters the micropyle, an opening in the female cone near the ovule. The pollen grain germinates and constructs a special pollen tube so that fertilization can take place. One of the two male gametes produced by the pollen then fuses with the female egg cell.
What happens after a female cone is pollinated?
The pollen grows a pollen tube, which enters a little hole in the ovule’s skin near its basal end, called the micropyle. The tube enters the ovule, and the sperm goes down the tube and into the ovule. When the sperm and egg fuse, fertilization occurs and the seeds grow.
What happens when the cone is wet or dry?
Cones close when conditions are unfavorable and rainy. The closing and opening of a cone’s scales is caused by swelling and shrinking of the cone’s plant cells. Closing occurs as the cells expand when wet and the scales shut tight, then the cells shrink as they dry out and the scales open.
What is the difference between cone-bearing plants and flowering plants?
Cone-bearing gymnosperms are designed to be pollinated by the wind, with male cones frequently arranged on branches above the females. Fruit-bearing angiosperms, on the other hand, are often pollinated by insects, birds or small mammals.
Which is the primary pollinator of conifers?
And what is the primary agent of conifer pollination? Wind. Conifers produce prodigious amounts of pollen, which is carried by the wind, often straight to the noses of susceptible humans. But the wind also delivers conifer pollen to the small, immature cones that develop into seed cones.