FIGURE 2:Development of the Embryo Sac

FIGURE 2:Development of the Embryo Sac

Development of the ovule

• The female gametophyte begins to develop within the ovules of the ovary.
• Within ovary, one or more ovules develop.
• Each ovule attached to the ovary wall (placenta) by short stalk called funicle.
• Main body of ovule is nucellus, which enclosed and protected by two sheath called integuments. 
• A small pore (micropyle) is left at one end of the ovule.
• The other end called chalaza.

FIGURE: Development of the pollen grains

Development of the pollen grains and the formation of the male gametes

1) Each anther comprises four microsporangia (pollen sacs)
2) Each microsporangium contain large number of diploid microsporocytes / microspore mother cells     (2n)
3) Each microsporocyte undergoes meiosis to form four haploid microspore cells (n).
4) Each microspore then undergoes mitosis, producing a haploid male gametophyte (immature pollen     grain) consisting only two cells tube cell and a generative cell.
5) Immature pollen grain then is transferred from anther to stigma and germinate.
6) The nucleus of generative cell will divide by mitosis to form two male gametes. Pollen grains now      become mature gametophyte.
7) Tube cell produces the pollen tube, which delivers male gamete to the egg.

Flowering plants

I Love Biology

Flowering plants are the dominant plant form on land and they reproduce by sexual and asexual means. Often their most distinguishing feature is their reproductive organs, commonly called flowers. Sexual reproduction in flowering plants involves the production of male and female gametes, the transfer of the male gametes to the female ovules in a process called pollination. After pollination occurs, fertilization happens and the ovules grow into seeds within a fruit. After the seeds are ready for dispersal, the fruit ripens and by various means the seeds are freed from the fruit and after varying amounts of time and under specific conditions the seeds germinate and grow into the next generation.

The anther produces male gametophytes which are pollen grains, which attach to the stigma on top of a carpel, in which the female gametophytes (inside ovules) are located. After the pollen tube grows through the carpel's style, the sperm from the pollen grain migrate into the ovule to fertilize the egg cell and central cell within the female gametophyte in a process termed double fertilization. The resulting zygote develops into an embryo, while the triploid endosperm (one sperm cell plus a binucleate female cell) and female tissues of the ovule give rise to the surrounding tissues in the developing seed. The ovary, which produced the female gametophyte(s), then grows into a fruit, which surrounds the seed(s). Plants may either self-pollinate or cross-pollinate.

ABOUT ME

WHO ARE YOU?

My name is Dayana. I do I love biology. My interest in Biology started at a very young age due to spending a lot of time outdoors. I am intrigued by the functioning of living organisms and how they are all linked; one small change in one species will affect a whole range of others. Maybe bacause as living beings that are totally dependent on other creatures for our existence it makes sense to have some kind of inbuilt fascination with how living things function and their complex relationships with each other. And perhaps biology seems more directly relevant to our everyday life in terms of questions such as how we evovled in the first place,why we get ill,inheritance etc. May not be that useful for a personal statement though! So let study about reproduction of flowering. Its my favourite subtopic in Biology ...




Have Fun Learning Biology!