Gerald F. Deitzer
gd3 at UMAIL.UMD.EDU
Mon Aug 2 13:10:50 EST 1999
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Ross mentioned growth under lighting, but nobody else has mentioned it. We find
that this is critical for experimental use. The biggest problem (fortunately) is
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 that
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 approach
with the foam. I am embarrassed to say that I missed his poster at the meeting
(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 useful
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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