In article ,
Jeff Thies wrote:
Billy wrote:
In article ,
"Paul M. Cook" wrote:
I sure beat the BER problem. It just took way more calcium than I ever
thought necessary. In the last 2 weeks I only lost 3 to BER after heavy
calcium supplements.
And you don't remember anyone telling you that BER happened at the
beginning of production and then went away?
A bit OT:
http://4e.plantphys.net/article.php?ch=3&id=289
Note the bit about calcium and growing region, which is related to the
above.
The interaction between nutrient mobility in the plant, and plant growth
rate can be a major factor influencing the type and location of
deficiency symptoms that develop. For very mobile nutrients such as
nitrogen and potassium, deficiency symptoms develop predominantly in the
older and mature leaves. This is a result of these nutrients being
preferentially mobilized during times of nutrient stress from the older
leaves to the newer leaves near the growing regions of the plant.
Additionally, mobile nutrients newly acquired by the roots are also
preferentially translocated to new leaves and the growing regions. Thus
old and mature leaves are depleted of mobile nutrients during times of
stress while the new leaves are maintained at a more favorable nutrient
status.
The typical localization of deficiency symptoms of very weakly mobile
nutrients such as calcium, boron, and iron is the opposite to that of
the mobile nutrients; these deficiency symptoms are first displayed in
the growing regions and new leaves while the old leaves remain in a
favorable nutrient status. (This assumes that these plants started with
sufficient nutrient, but ran out of nutrient as they developed). In
plants growing very slowly for reasons other than nutrition (such as low
light) a normally limiting supply of a nutrient could, under these
conditions, be sufficient for the plant to slowly develop, maybe even
without symptoms. This type of development is likely to occur in the
case of weakly mobile nutrients because excess nutrients in the older
leaves will eventually be mobilized to supply newly developing tissues.
In contrast, a plant with a similar supply that is growing rapidly will
develop severe deficiencies in the actively growing tissue such as leaf
edges and the growing region of the plant. A classic example of this is
calcium deficiency in vegetables such as lettuce where symptoms develop
on the leaf margins (tip burn) and the growing region near the
meristems. The maximal growth rate of lettuce is often limited by the
internal translocation rate of calcium to the growing tissue rather than
from a limited nutrient supply in the soil.
When moderately mobile nutrients such as sulfur and magnesium are the
limiting nutrients of the system, deficiency symptoms are normally seen
over the entire plant. However the growth rate and rate of nutrient
availability can make a considerable difference on the locations at
which the symptoms develop. If the nutrient supply is marginal compared
to the growth rate, symptoms will appear on the older tissue, but if the
nutrient supply is very low compared to the growth rate, or the nutrient
is totally depleted, the younger tissue will become deficient first.
I'll have to reread this later, it certainly explains a lot to me.
Perhaps excess mobility in some nutrients inhibits slow moving nutrients
like calcium. Just speculating...
Jeff
You are such an idiot.
Leave the branches alone. This is what tomato plants do.
I don't doubt that this is what happened. The plant in its vigorous
vegetative stage was unable to take-up the calcium that it needed due to
dry roots, nutrients being flushed away, or high temps which simply
required water for evaporative cooling with no Ca transport. So the
above is a very good answer to a question that I didn't ask ;O)
My question was to the Balvenieman, who wrote on Thu, 15 Jul 2010
14:02:52 that "Excesses of certain micro-nutrients -- magnesium, for
example -- can interfere with plants' ability to acquire and/or to
transport Ca."
I was just wondering if he had a citation for it because I had always
heard that a deficiency of Mg would affect Ca transport, as a result,
some would use epsom salts in a foliar spray on their plants to try to
alleviate this condition, but I have never heard of an excess of
magnesium as being a problem. It is true that an excess of boron or NO3
can hamper Ca transport, but that wasn't the question.
--
- Billy
"Fascism should more properly be called corporatism because it is the
merger of state and corporate power." - Benito Mussolini.
http://www.democracynow.org/2010/7/2/maude
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