Nitrate in Plant Tissues

Elaine M. Shea shea at LOYOLA.EDU
Tue Aug 3 14:59:19 EST 1999

I got the following question from the folks who make a nifty nitrate test
kit (based on nitrate reductase).  I use the kits for a lab activity, but
this question strays a little out of my league.  Can anyone help?

>We've been getting info requests from farmers in Ohio.  Because of the
>drought, there's a lot of trouble with nitrate levels in the corn, both for
>feed and silage purposes.  The crop consultants and feed suppliers are
>looking for ways to measure the nitrate content of the corn at
>harvest.  We've done quite a bit of work with using our test kits to
>measure nitrate in plant tissues, but we generally boil and/or freeze/thaw
>to be sure to get all the nitrate out of the vacuoles.
>So here's the question:
>Is there any known ratio between the nitrate level in the cytoplasm and
>that level in the vacuoles?  We want to tell these guys how to measure
>nitrate by just squeezing out some of the plant juice (from leaf or stalk),
>diluting it by a factor of 1000 (they're telling me there's nitrate at 1000
>- 15000 ppm in the corn!!), and using a 50 µl drop of the dilution in our
>test kits.  If they do this, is there any way to guesstimate how much total
>nitrate is in the plant?
>Any info or leads accepted here. We not only want to sell test kits, we'd
>like to help the farmers.  When nitrate levels are this high, the
>fermenting silage makes toxic nitrous oxide gas - people die from this.
>Best regards,
>Ellen R Campbell, Vice President
>The Nitrate Elimination Co., Inc.
>334 Hecla Street
>Lake Linden, MI 49945
>Phone: 906/296-1000  Toll Free:  888/NITRATE
>Fax: 906/296-8003
>Web Site URL:
>NECi: Biotechnology people can use!

You can reply to the group or to me directly and I'll see that Ellen gets them.


Elaine M. Shea
Chemistry Department
Loyola College
4501 N. Charles St.
Baltimore, MD 21210

Phone: 410-617-2058
FAX: 410-617-2646
email: shea at

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