[Arabidopsis] brands of agar
(by cramer from unr.edu)
Wed Feb 13 14:15:32 EST 2008
Sorry for the confusion. I miswrote. I meant Phytagel not PhytoAgar.
That was a brain short circuit!
Grant R. Cramer
Department of Biochemistry and Molecular Biology, MS 200
University of Nevada, Reno
Reno, NV 89557
cramer from unr.edu
On Feb 13, 2008, at 6:29 AM, Tobias Baskin wrote:
> In replies to this thread, Grant Cramer mentions
> "PhytoAgar" and Brian Forde mentions "PhytagelTM" which I think is
> the same phytagel we used awhile back too. But is PhytoAgar the
> same stuff as Phytagel? or are they different? Do you know?
> At 4:40 PM -0800 2/12/08, Grant Cramer wrote:
>> I have found very negative effects on root growth using BactoAgar
>> both from batches in the United States and Australia. I have NEVER
>> had a problem with PhytoAgar on root growth in root length assays
>> up to a week. After that they are in the dish for too long and
>> will suffer. One can supplement with sucrose in a standard quarter
>> strength Hoaglands solution without problem. I agree you should
>> not use MS medium or you will suffer from osmotic stress and
>> perhaps other things that are out of balance for roots. The roots
>> will grow without the sucrose but slower. It depends on your
>> experiment, but those shaded cotyledons in a plastic petri dish
>> can only do so much in the dark or dim light. I always grow them
>> in the dark, as light inhibits root growth.
>> Grant R. Cramer
>> Department of Biochemistry and Molecular Biology, MS 200
>> University of Nevada, Reno
>> Reno, NV 89557
>> (775) 784-4204
>> cramer from unr.edu
>> On Feb 11, 2008, at 6:33 AM, Tobias Baskin wrote:
>>> Dear Tanya,
>>> Some years ago, we investigated a variety of different
>>> agars (some of which you mention). We found reproducible
>>> differences in root elongation rate but perhaps on the order of
>>> 10 to 20 %. Clearly the roots liked some agar better than others.
>>> We also found a little bit later when using phytagel that root
>>> elongation rate depended on the temperature the molten mix was
>>> held at before pouring, or might have simply been quite
>>> irreproducible. But again I am talking about differences on the
>>> order of 20%. Big enough to readily measure but not monstrous. On
>>> no agar did we see the kind of developmental change you are
>>> mentioning. On some conditions I have seen (and read) that
>>> severely salt stressed or water deficit stressed roots will swell
>>> so I'd guess what you are describing goes way beyond what can be
>>> expected from different brands/formulations of agar.
>>> Hope this helps,
>>> At 3:10 PM -0600 2/9/08, Falbel, Tanya G. wrote:
>>>> Over the years, I've used several brands of agar for growing
>>>> Arabidopsis seedlings on MS medium,
>>>> from Gibco, Sigma, and others. I've heard that some groups use
>>>> Noble agar,
>>>> others, bacto-agar, others in the past have washed their own
>>>> agar, used phytagel or other
>>>> gelling agents. I have two questions:
>>>> 1) What brands of agar are most commonly in use now by groups?
>>>> I've found something similar
>>>> to Gibco's Phytagar that is now available through Caisson labs.
>>>> Other groups seem to like Sigma's
>>>> A1296. But besides those, what do most groups use? I'm
>>>> especially interested in the opinion of
>>>> groups that measure root length or root branching - growing
>>>> roots vertically on plates
>>>> for more than just a couple of days. (as opposed to just
>>>> antibiotic selection)
>>>> 2) Does anyone know what inhibitors are washed away? Are
>>>> micronutrient ions or other toxic
>>>> compounds bound to the crude agar? Has anyone looked into this?
>>>> This may have been a question
>>>> that came up among researchers 10 years ago, but I couldn't find
>>>> any record in the archives.
>>>> Here's why I'm asking. I made up a batch of medium with a brand
>>>> of 'purified agar for microbial use',
>>>> and got a very strong inhibition of root meristems. Seed
>>>> germination was good, but roots failed to elongate
>>>> any further after about 4 days of growth. The root meristems
>>>> became a swollen mess, reminiscent of what
>>>> happens in weak gnom alleles. I'm trying to decide if this is
>>>> something worth looking into.
>>>> I know that for regeneration of plants in tissue culture, folks
>>>> are very fussy about particular brands of agar.
>>>> Please let me know what brands you have used with success or
>>>> I'd be especially interested in other similar experiences -
>>>> where a brand
>>>> wreaked havoc on root meristems.
>>>> Tanya Falbel
>>>> Department of Biology
>>>> 105 Garfield Avenue
>>>> University of Wisconsin-Eau Claire
>>>> Eau Claire, WI 54702-4004, USA
>>>> Tel: 715-836-5087
>>>> Fax: 715-836-5089
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>>>> Arab-gen from net.bio.net
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