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
><mailto:cramer from unr.edu>cramer from unr.edu><http://www.ag.unr.edu/cramer/>http://www.ag.unr.edu/cramer/>>>>On Feb 11, 2008, at 6:33 AM, Tobias Baskin wrote:
>> 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
>>>> 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
>>>>>>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 failure.
>>>I'd be especially interested in other similar experiences - where a brand
>>>wreaked havoc on root meristems.
>>>Department of Biology
>>>105 Garfield Avenue
>>>University of Wisconsin-Eau Claire
>>>Eau Claire, WI 54702-4004, USA
>>>Arab-gen mailing list
>>><mailto:Arab-gen from net.bio.net>Arab-gen from net.bio.net>>><http://www.bio.net/biomail/listinfo/arab-gen>http://www.bio.net/biomail/listinfo/arab-gen>>>>>>>>>--
>> _ ____ __ ____ / \ / / \
>>/ \ \ Tobias I. Baskin
>> / / / / \ \ \ Biology Department
>> /_ / __ /__ \ \ \__ 611 N. Pleasant St.
>> / / / \ \ \ University of Massachusetts
>> / / / \ \ \ Amherst, MA, 01003
>>/ / ___ / \ \__/ \ ____
>><http://www.bio.umass.edu/biology/baskin/>http://www.bio.umass.edu/biology/baskin/>>Voice: 413 - 545 - 1533 Fax: 413 - 545 - 3243
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