What does 4N mean?

[Orchidflowerchild]

Originally Posted by newflasker

Hi Orchidflowerchild,
Thank for your information. Some questions: What does it mean sterile? It means we cannot sexual reproduction , right? How about asexual reproduction? Can we reproduce using cells/meristem in micropropagation? Have you ever done with tri/tetraploidy conversion? do you use colchicine or what? How difficult to do the conversion? Thanks.

Yes, I mean that they are sterile sexually. They can be divided and cloned, but never (or very rarely) bred with.

The cross of a tetraploid and a triploid would still not work, for the same reasons a triploid and a diploid wouldn't The triploid does not have the chromosomes to divide and fuse to the chromosomes of the other parent.

I have never used Colchicine. I would not recommend it for home use, either. It is a VERY dangerous carcinogen. It causes drastic mutations at the chromosomal levels with people just as efficiently as plants.

-Cj

[maitaman]

Something to take into consideration when speaking of genetic variations is that orchids have some very interesting features that allows "floating genes" to enter into the process - which makes the seed-carrying parent sometimes have very strange dominant characteristics that often will not carry into further generations.
Orchid genetics have some unexpected twists and turns.

[Orchidflowerchild]

Very true. Extranuclear genes, especially mitochondrial DNA can have pretty dramatic results int he offspring. Suffice it to say, orchids are very non-mendelian.

-Cj

[Gwenchanter]

Wow this is facinating! I absolutely loved genetics in my biology class at school, so I have a good understanding of "normal" mendelian genetics. Where can I get more information about the nitty gritty of orchid genetics?

[goodgollymissmolly]

I certainly agree with essentially everything Cj says. However, there is no literature that I can find that says colchicine is a carcinogen. (Check the link below).

Colchicine is a polynuclear hydrocarbon with two unsaturated rings and one saturated one. It is derived from the autumn crocus. It is a primary agent for the treatment of gout in both an acute and routine preventative protocol. It does have potential serious side effects and is a poison at high dosages with no antidote. It has been approved by FDA since 1939.

It prevents cell division so it seems to be a natural, anticancer chemotherpy candidate though little human data exists. Veterinarians have used it to treat cancer in other animals.

Many people use it in horticultural efforts to produce polyploid (especially tetraploid) plants. I have never heard of any of these people having any negative health effcts as a result. It is used differently for different plants. For instance, in daylilies it is usually used to treat the meristem of growing plants. Apparently in orchids, it is usually used to treat protocorms. People have also treated seeds (or germinating seeds) of many plants.

If you are not comfortable handling chemicals, this is not for you. It is difficult to buy because it is a poison, but it is not illegal and is available. Exercise care to avoid contact. Very simple link below:

Cyberbotanica: Colchicine

PS..this a tetrogen, although it does not appear to be a carcinogen.

[maitaman]

Chemicals of this type can be extremely dangerous, not so much as a carcinogen as an alergy institutor -- to the point of anaphylaxis. Colchicine was shown to be among the worst at producing pulmonary fibration among those trying to produce polyploid marijuana in the 60's. A number died rather unpleasant slow deaths from simply smoking the product that still had residual traces of the chemical on it.
Take extreme care with all chemicals. These kinds of things can cause genetic damage that shows in your offspring when you have no personal symptoms. "Agent orange" is just a mixture of plant hormones.

[Gin]

Interesting thread , I understand bird genetics , lately been trying to learn plant Thanks for the cool info. Gin