plant nutrient deficiency experiment

Michael Grusak mgrusak at BCM.TMC.EDU
Thu Feb 22 17:05:21 EST 1996


>To: plant-ed at net.bio.net
>From: metz at camel.campbell.edu (Tim Metz)
>Subject: plant nutrient deficiency experiment
>Date: 22 Feb 1996 11:14:57 -0800
>Sender: daemon at net.bio.net
>NNTP-Posting-Host: net.bio.net
>
>I've got a question about a nutrient deficiency experiment I'm trying to
>run in intro botany lab.  I'm following the experiment in Vodopodich and
>Moore's "Botany" lab manual on p160-161.  I had the experiment set up on
>Monday, with tomato seedlings (about a month old) growing in perlite and
>being watered with Hoagland's solution minus one of the essential
>nutrients.  The problem is, the plants in all treatments but the "water
>only" control are dying.  Now, I've got a couple of flats of backup tomato
>seedlings that I can use, but I need to figure out why the plants are
>dying.  The only chemical I substituted from the Hoagland's solution recipe
>listed in Vodopodich  and Moore is Molybdenum trioxide instead of
>H2Mo4*4H2O .  Could that have caused the problem?  Any suggestions??
>
>Thanks!
>
>
>Timothy D. Metz
>Assistant Professor of Biology
>metz at camel.campbell.edu
>
>Biology Department                               Faculty Advisor
>Campbell University                              Alphi Phi Omega
>P.O. Box 308                                     Nu Kappa Chapter
>Buies Creek, NC 27506
>1-910-893-1732 or
>1-800-334-4111, ext. 1732
>1-910-0893-1424 (fax)
>
>
>
>
Tim,
It's hard to say what your problem is without more input on the physical
symptoms of your dying plants.  I'm not familiar with the instructions in
the lab manual you're working from, but I'm wondering what the pH of your
solutions might be?  - not the starting solutions, but final solutions after
some period of plant growth.  Depending on the volume of nutrient solution
and the size of the root system, you could easily deplete certain ions
within a short period of time and the influx of remaining ions (along with
concommitant proton efflux) could quickly lead to acidic conditions.  How
often are the solutions changed?  What is yor buffer?

In our hydroponic work, our biggest problem is always fighting solution
acidification and the resulting acid stress of the roots.  Severe acid
stress could easily lead to plant death.

Mike Grusak

************************************************

Michael A. Grusak
USDA-ARS
Children's Nutrition Research Center
1100 Bates Street
Houston, TX  77030

phone: 713-798-7044
FAX:   713-798-7078
e-mail: mgrusak at bcm.tmc.edu
http://www.bcm.tmc.edu/cnrc/faculty/grusak.html

Learn what our lab and others are doing in the 
area of micronutrient nutrition. See:
http://www.fas.org/pub/gen/fas/mnp/micro.html

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