Re: 'Indian Giant' ploidylevel [was:Re: Sauromatum x Pinellia hybrid]

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-----Original Message-----
> Date: Wed, 07 Jul 2010 21:03:55 +0200
> Subject: Re: [Aroid-l] Sauromatum x Pinellia hybrid.... and others...
> From: James Waddick <j*@kc.rr.com>
> To: Discussion of aroids aroid-l@www.gizmoworks.com
....

> In this same discussion, the cv "Indian Giant' is brought to
> mind. This is a much larger form of S. venosum. Could it be a
> tetraploid? Has anyone compared chromosome numbers to the typical,
> smaller form? And is this, by the way, any more or less hardier than
> the typical form?

Dear Jim W.,

Aroiders,

already more than one year ago I compared the ploidy level of a normal form of Typhonium venosum (a genotype/tuber that came from Laos) with my 'Indian Giant' clone that was originally introduced by Tony Avent (Plant Delights Nursery). Furthermore I have the clone that was given to me as T. nubicum. but is probably identical with 'Indian Giant'.

For pictures see: (scroll down to the post from 06.11.2009)

http://www.amorphophallus-forum.de/viewtopic.php?f=9&t=316&start=30

I did not count the chromosomes but used flowcytometry to compare the DNA content.

In short words with this method the DNA content of nuclei is measured after the DNA was stained.

The measured values are shown in a graph.

The first peak represents the cells in the G1-phase; this would give the DNA-content of somatic cells. The second peak represents the nucelar DNA content of cell in the G2-phase after the replication of the DNA before the cell devides.

The graphs show the measurements of T. venosum 'Laos', T.venosum 'Indian Giant' and T. nubicum, respectively.

[img]http://i82.photobucket.com/albums/j260/Mr_Titanum/T_v_Laos.jpg[/img]

[img]http://i82.photobucket.com/albums/j260/Mr_Titanum/T_v_IndianGiant.jpg[/img]

[img]http://i82.photobucket.com/albums/j260/Mr_Titanum/T_nubicum.jpg[/img]

The results strongly indicate that the three clones do not differ in DNA content and therefore have the same ploidy level.

However, I did no chomosome counts, but if 'Indian Giant' would be a tetraploid of the normal form of T. venosum, the graph should show a first peak at channel 100 for the G1-nuclei and a second at channel 200 for the G2-nulei. This is not the case; all three clones have the peaks roughly at channel 50 and channel 100.

Best, Bernhard.

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