Seed Production in Gymnosperm

The adult sporophyte (e.g. pine tree) develops male and female cones on separate branches. Female cone develops two ovules on the upper surface of each cone scale; each ovule contains haploid megaspore. Male cones produce microspore by meiosis. The microspores develop into pollen grains. Each winged pollen grain is a four-cell male gametophyte. The female gametophyte grows producing two or more archegonia, each of which contains an egg. During pollination, a wind-born pollen grain falls near the opening in one of the ovule of the female cone. Each male gametophyte form a pollen tube that penetrate the tissue of the female gametophyte. When the pollen tube has grown into an archegonium, a sperm cell from the male gametophyte fertilizes the egg. The zygote develops into an embryo and a mature seed is produced. The female cone opens releasing the seeds. When condition is favourable the seed germinates to a new young sporophyte - a pinetree seedling.

Category:

Education

Tags:

• sporophyte
• gametophyte
• cones
• megaspore
• microspore
• archegonium
• pollen
• grain

[Stoga334]

i like how the when the male pollen grain extends it looks just like a penis

[kartoonkid49]

Helped me out. Thanks.

[slackkeylady]

The seeds, like the leaves, do not 'fall' off the tree. They jump! Hence the gym in gymnosperm.

[star4galaxy]

ahhh... if only i had found this when i needed it on my biology test!!!!!!1

[khatrirahul12]

gug hai yar...bt still nt workin

[superrozza]

@x1xAMxL3G3NDx lol thinking the same thing

[FHBabii]

@agorski3 No. They are motile but are dispersed by wind/insects

[x1xAMxL3G3NDx]

Does anyone else notice the relationship between this and humans? Such as the shape and function of the pollen tube?

[bob140988]

No that is the case fore some plants like Polypodiopsida and mosses but cyads and ginko transferee there spores by air and (insect or wind) and the only place that they need to swim is inside the female plant on there way to the egg.

[agorski3]

so in cycads and ginko is there is need for water for the sperm to swim?

[mehtadevika25]

Its a great video. I have sent you a message to request you to grant me permission to use this video. Please kindly reciprocate soon to the message. Thank you.