Grant R. Cramer
cramer at UNR.EDU
Mon Aug 2 14:17:42 EST 1999
Actually your light conditions are way too low (which is what most people
grow them at). Light saturation for photosynthesis in Arabidopsis occurs at
about 600 µmol m-2 sec-1. See Eckardt et al. (1997) Plant Physiol
113:575-586 for the data.
Grant R. Cramer
Mail Stop 200
Department of Biochemistry
University of Nevada
Reno, NV 89557
phone: (775) 784-4204
fax: (775) 784-1650
email: cramer at med.unr.edu
web page: http://BIOCHEM.MED.UNR.EDU/faculty/grant_c/
>From: gd3 at umail.umd.edu ("Gerald F. Deitzer")
>To: plant-ed at net.bio.net
>Subject: Growing Arabidopsis?
>Date: Mon, Aug 2, 1999, 11:10 AM
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> Ross mentioned growth under lighting, but nobody else has mentioned it. We
> that this is critical for experimental use. The biggest problem (fortunately)
> too much light. Arabidopsis is a shade adapted rosette plant and cannot
> tolerate very bright light. We find that 100-150 umol/m2/s of PAR is more
> adequate, even under very short daylengths (8-hr). Addition of incandescent
> light to long photoperiods (16-24-hr) will hasten flowering in all ecotypes.
> Otherwise we have always used 1/4-1/8 strength Hoagland's #1 Solution in a
> semi-hydroponic system similar to that described by Jon Monroe earlier in this
> discussion. The Rockwool sounds like a good idea as does Rich Arteca's
> with the foam. I am embarrassed to say that I missed his poster at the
> (there were only 1,000 of them to deal with) as well, even though I did get a
> chance to talk to him somewhere in the poster room. This has been a very
> Gerry Deitzer
> Ross Koning wrote:
>> Hi Grant!
>> One point I failed to make in my previous post was that
>> I also remind students to handle the phytagel block
>> directly rather than lift the phytgel block by pulling
>> on the seedling.
>> I haven't tried rockwool yet so I'm not clear about
>> growth rates and final size. The phytagel move to
>> Fafard #2 for us has resulted in plants about 30-40
>> centimeters (to top of inflorescence) and with perhaps
>> 25 basal rosette leaves. I don't know whether that is
>> "puny" or not...but I have been happy with the size
>> and growth rate. We grow under lights and this size is
>> almost too-big as it is (inflorescences getting crowded
>> and possible cross-pollinations). So, if that IS puny
>> and your method gives significantly larger plants, I'm
>> not sure it would help in our situation. Please advise
>> on this as it is important to know whether our plants
>> are indeed abnormal or not. If I can get my hands on some
>> rockwook I'll give it a try to see if I like it better.
>> I do have one other question, though, and that is safety.
>> With the asbestos problem, and with parallel fiberglass
>> legislation "in the works", dare we use rockwool in
>> teaching? I have become quite concerned even with using
>> perlite...I do use it, but have the students wet it down
>> immediately to avoid its dust. And, when you are done
>> with rockwool, is there any problem with disposal?
>> Currently I put our greenhouse waste in my home compost
>> pile (since the ECSU greenhouse is pesticide-free), but
>> I think I would put rockwool in our university trash-stream.
>> I'm wondering if trash contractors would have a problem
>> with it mixed in with the rest of the trash.
>> At 10:52 AM -0400 8/2/99, Grant R. Cramer wrote:
>> >We have tried this method as well (and about 200 others!). There are two
>> >problems with this technique: One, although the roots grow in phytagel and
>> >agar, they grow much more slowly than in rockwool. I suspect that aeration
>> >is inadequate. Plants are downright puny when grown by this method. And two,
>> >there is a big problem with transplant shock (as you pointed out), even if
>> >you include the gel (because it is quite soft and floppy). These seedlings
>> >are tiny and very delicate. With rockwool, you won't have aeration problems
>> >and if you must transplant, you can plant in a large enough cube and the
>> >material is firm enough that you can transplant without shocking the plant.
>> >Grant R. Cramer
>> >Associate Professor
>> >Mail Stop 200
>> >Department of Biochemistry
>> >University of Nevada
>> >Reno, NV 89557
>> >phone: (775) 784-4204
>> >fax: (775) 784-1650
>> >email: cramer at med.unr.edu
>> >web page: http://BIOCHEM.MED.UNR.EDU/faculty/grant_c/
>> >>From: koning at ecsuc.ctstateu.edu (Ross Koning)
>> >>To: plant-ed at net.bio.net
>> >>Subject: Re: Growing Arabidopsis?
>> >>Date: Sun, Aug 1, 1999, 2:21 PM
>> >> Getting the seeds to sprout on a simple mineral-
>> >> phytagel plate is easy (I have used MS salts and
>> >> Knopps with equal success). The problem comes when
>> >> students try to move them to soil. The young seedlings
>> >> can take NO root-abuse in that stage. The problem here
>> >> was solved by letting the students move each seedling
>> >> with the phytagel INTACT...carving out a block that
>> >> included the root and planting the whole block. Once
>> >> I figured that out, all my students had success with
>> >> their "mystery mutant" arabidopsis plants. To get the
>> >> seeds sown in the plates thinly enough I found that
>> >> a SMALL quantity of seeds in a microfuge tube are held
>> >> well on the walls of the tube by static electricity
>> >> (or other forces). This allows the student to tap
>> >> on the tube to release just one seed at a time and
>> >> get them spaced apart widely in the dish so that
>> >> root damage can be minimized at the transplant time.
>> >> ross
>> Ross Koning | koning at ecsu.ctstateu.edu
>> Biology Department | http://koning.ecsu.ctstateu.edu/
>> Eastern CT State University | phone: 860-465-5327
>> Willimantic, CT 06226 USA | fax: 860-465-4479
>> Electronic services composed and served from Macintosh hardware.
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