David R. Hershey
dh321 at PGSTUMAIL.PG.CC.MD.US
Thu Mar 4 22:58:40 EST 1999
Nickel is also now being listed as an essential element for higher plants.
One key difference worth pointing out is that deficiency symptoms occur
naturally or under agricultural conditions for the six macronutrients and
micronutrients Fe, B, Mn, Cu, Zn, and Mo. Deficiencies of other elements
have to be induced under lab conditions because they are present in the
environment at adequate levels.
David R. Hershey
dh321 at mailexcite.com
On 4 Mar 1999, Carl Pike wrote:
> For years I've made general-use nutrient solutions with what I suspect is a
> standard recipe (it's in the Machlis and Torrey lab manual, for those of
> you who go back that far, and also in the Reiss lab manual). Only today
> did I notice that this recipe has no chloride - nitrate, phosphate, and
> sulfate are the major anions. Chloride is not an essential element, but
> then whenever we talk about guard cells we say that chloride (as well as
> malate) is the major counterion. Indeed, discussions of the general
> electrophysiology of plant cells seem always to involve chloride.
> So how come if chloride is so important it isn't in the nutrient solution?
> Chloride does get added when one is, for example, making a solution lacking
> nitrate -- substitute KCl for KNO3. How do plants without chloride manage
> their membrane potentials, open/close their stomata, etc.? Can they do it
> with the other anions? Am I missing something?
> Carl S. Pike (717) 291-3958
> Department of Biology FAX (717) 399-4548
> Franklin and Marshall College email C_PIKE at ACAD.FANDM.EDU
> P.O. Box 3003
> Lancaster, PA 17604-3003 USA
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