Thursday, August 26, 2010

Naked Jackfruit - how does it happen

Naked Jackfruits
Once in a while we may come a crossed a jackfruit, with it’s fruitlet exposed and not covered with the fruit skin. This phenomena is quite normal, but not usual. These jackfruits are often called the naked jackfruits.

A lot of us may aware that jackfruits are categories as compound fruits or multiple fruits similar to that of annonas, soursops, strawberries and alike.

Botanically, the whole fruit structure is made up of a bunch of fused fruits. To help u to visualize this, just imagine a bunch of oil palm fruits, with the entire fruitlets in the bunch are fused together, and it appears like it is forming a single fruit.

For jackfruits, each of the thorny structure on the outer skin of the fruit, is actually the tip of a flower. These little flowers (the thorny structures) are fused to form a whole fruit.

For jack fruits, the male and female flowers are on separate stalks. These kind of flowers are called dioecious or having ‘two separate home for the different gametes’. In contrary, in most plants male and female flowers are placed in the same flowers and they are called monoecious flowers.

The female flowers consists of several parts. The most vital part is the ovules, that will turned into seeds after fertilization. The seed will carry the embryo for the growth of the next generation. The ovules are housed in a structure called ovary, where in most plants the ovary will develop into fruits on ripening. However, there are plants where the addible part are develop from other than overy.

The ovary wall will usually extended to form a tube like structure called style and at the tip of the style is a structure known as stigma.

Pollen grain from the male flowers will be landed on the stigma, will germinate and will fertilized the ovule at the base of the female flower parts.

If you observe the young female flower of jackfruit just before the anthesis, you will observed that at every tip of the flowers, the thorny struture, you will fine a tripot-like structure, white in colour. This is the stigma of the flower.

A matured male flowers usually will be covered with yellow coloured powder-like materials. And these yellow substance is actually the pollen grain of the jackfruit flowers. Millions of these pollen will be blown around and will be disseminated by winds and the chances are, some of the pollen will be landed on the stigma of the female counter part, and that will complete the pollination process. On fertilization, the ovule will develop into zygote and will later develop into embryo, a potential new plant in the making.

What happened to the naked jackfruit?

Along the growing process, especially during the genetic recombination in the fertilization process, some form of mutation occurred, where the offspring will develop fruits with poorly fused flowerlet, As the fruits develop further, the fused structure detached and that will result in the fruit skin to develop cleavage. The union that holds the fruit skin together became detached and that will expose the fertilized ovule.

As the results of the cleavage, these fruits has no restriction in it’s growth and usually these fruits will develop bigger and longer than those fruits that develop under the fused coverage of the outer skin. These ‘freed’ fruits elongated and develop into more like a banana rather than jackfruit.

1. Anthesis – the stage of development of the flower just before the receptive stage.
2. Receptive stage – the development stage of the female flower when the ovary (ovule) is ready to accept male gamete to be fertilized.
3. monoecious – male and female gamete placed in the same flower
4. dioecious – male and female gametes placed is separate flowers
5. ovule- the female gamete
6. ovary – the structure that housed the female gamete
7. zygote - the female gamete after being fertilized by the male gamete
8. embryo – develop zygote
9. style – extended structure from overy th hole dht stigma out of the flower structure in order to expose the stigma to help in the pollination.
10. stigma
11. pollination – Transfer of male gamete into female counterpart.
12. Fertilization – Fusion of male and female gamete
13. pollen grain – male gamete.

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