How Do Nutrients Affect Flower Color Expression?
Larry Dighera
I recently purchased a Epidendrum elongatum with very rich purple
flowers. Flowers which bloom now are nearly lavendar-pink. Can
anyone offer a reasonable cause for this change in color expression?
Is there any particular general knowledge regarding the relationship
of nutrients or pH to flower color expression? Hydrangea can change
from pink to blue with a change to pH 5:
http://www.ag.uiuc.edu/~robsond/solutions/horticulture/docs/hydrange.html
Aluminum must be available in the soil for blue to be produced. Acid
soils usually contain plenty of aluminum. An aluminum sulfate drench
is used to achieve blue flowers in neutrial soils.
bbbbbb
Ray @ First Rays Orchids
aluminum sulfate is just for increasing the pH, not for adding the Al. I'd
bet that a different metallic base would do the same.
--
Ray Barkalow <> First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info!
"Larry Dighera" <LDig...@att.net> wrote in message
news:uouqku8pvk7v4lpde...@news-server.socal.rr.com...
Larry Dighera
<ray...@firstrays.com> (Ray @ First Rays Orchids) wrote in Message ID
<_Kh39.28859$yc3.1...@bin4.nnrp.aus1.giganews.com>:
>Are you certain about the need for aluminum for blue color?
A Yahoo search provided information to the effect, that HYDRANGEA
needs Al to express blue flowers. Because most soils contain adequate
amounts of Al, lowering the pH is sufficient to turn their flowers
blue. It seems that nuteral-to-basic pH prevents the plant from
assimilating the Al in the soil.
Here are a few citations:
http://www.ces.uga.edu/Agriculture/horticulture/hydrangea.html
"Research has determined that the actual mechanism of color
variation is due to the presence or absence of aluminum compounds
in the flowers. If aluminum is present within the plant, the color
is blue. If it is present in small quantities, the color is "in
between," and if it is absent, the flowers are a pink.
The soil pH indirectly affects the color by affecting the
availability of aluminum in the soil. When the soil is acid,
aluminum is generally more available to the roots. When the soil
is alkaline, the availability of aluminum is decreased and the
flowers are more pink."
http://www.hydrangeashydrangeas.com/colorchange.html
"To make the aluminum available to the plant, the pH
of the soil should be low (5.2-5.5). Adding aluminum
sulfate will tend to lower the pH of the soil.
[...]
The choice of fertilizer will also affect the color change.
A fertilizer low in phosphorus and high in potassium is
helpful in producing a good blue color(25/5/30 is good.
Potassium is the last number). Superphosphates and
bone meal should be avoided when trying to produce
blue.
[...]
The pH of the water should not be higher than 5.6."
http://www.gardenpower.com/projects/joes/99036.htm
>I think the aluminum sulfate is just for increasing the pH, not for adding the Al.
Actually, aluminum sulfate lowers the pH and provides Al.
>I'd bet that a different metallic base would do the same.
If it were acidic, it would probably make the Al in the soil
accessible.
Have you ever experienced any change in the color expressed by any of
the orchids you flower? This is a first for me.
Diana Kulaga
I can't answer the question about nutrients, but I have a number of plants
that either: (A) change flower color as the plant blooms and the
inflorescence ages; or (B) produce somewhat different colors upon
successive bloomings. From what I understand it's a fairly common
phenomena.
Diana
Larry Dighera
Many thanks for your astute insight on this arcane issue.
I did a little online Anthocyanin research, and have a little better
understanding of the effects of pH, light intensity, UV radiation,
available phosphorus, temperature, Fe+3 and Al+3, nutrient stress, and
age of flower tissue impose on the anthocyanin system of some plants.
I can see where a number of those factors affected my formerly vivid
purple Epi.
Thanks again for the pointer.
On Tue, 6 Aug 2002 17:49:17 -0400, "Al" <A...@orchidexchange.com> (Al)
wrote in Message ID <aipg92$cn3$1...@bob.news.rcn.net>:
>the purple/red pigment, anthocyanin, is known to be temperature sensitive.
>Cooler temps, even of just a few degrees, at a critical stage in bud
>formation will result darker flowers. Warmer temps while the flower is
>forming will result in less intense pigmentation. This is most remarkable
>when older bud on the same inflorescence 'ripen' at different temperatures
>then younger buds.
http://fastplants.cals.wisc.edu/FAQ/Anthocyanin.html
Purple Anthocyanin
Q1: What is the reddish-purple pigment I see in my Fast Plants?
This pigment is known as "anthocyanin." Anthocyanin expression is
controlled by both genetic and environmental factors. Purple is
a simple dominant Mendelian trait, with quantitative expression.
Though much is known about the anthocyanin system in other
species, the complexity of this system in Brassica rapa is just
now being explored.
The genetics of anthocyanin expression are complex. The placement
(i.e., location on the plant) of anthocyanin expression is under
genetic control. Paul Williams, director of the Fast Plants
program and professor of Plant Pathology, is currently in the
process of extracting one gene controlling this placement. It
appears as if there is one major gene controlling the expression
in many locations (hydathodes, bud tips, etc.). The intensity of
expression at a given location is controlled by many other genes,
each of immeasurable and varying effect.
Expression of anthocyanin is also influenced by factors in the
growing environment. Light intensity is critical: strong, high
light is recommended for high levels of expression. Anthocyanin
expression is controlled by a phytochrome-mediated system, so
wavelengths in the red portion of the spectrum are especially
influential. The plants also need to be separated from each other
so that they can receive the light.
Nutrient stress is also an environmental factor which can affect
the levels of anthocyanin expression - plants grown under low-end
levels of N-P-K will show higher levels of the pigment.
The anthocyaninless mutation (anl/anl) can be superimposed on this
genetic background. This mutation completely shuts down
anthocyanin production and expression in the plant. Having a
genetically anthocyaninless plant in the same growing environment
as the purple plants provides a good control for measuring
expression of the pigment.
Some useful references on anthocyanin and other plant pigments
include the following:
Chichester, C.O. 1972. The Chemistry of Plant Pigments.
Academic Press (New York).
Goodwin, T.W., ed. 1976. Chemistry and Biochemistry of Plant
Pigments. Academic Press (New York).
Mazza, G. 1993. Anthocyanins in Fruits, Vegetables and
Grains. CRC Press (Boca Raton, FL).
Michigan State University. 1996. "Anthocyanin pigments of
flowers and vegetables." Natural Science, Especially for
Teachers Section (spring/summer).
http://newcrop.hort.purdue.edu/rhodcv/hort640c/secprod/se00013.htm
http://farma.qfb.umich.mx/maize2.htm
Anthocyanins are chemical molecules produced when a plant is under
stress conditions.
One of the first morphological changes observed was that hypocotyl
in treated seeds starting at 50 ppm of copper, showed a clear
reddish color indicative of an increased anthocyanin synthesis
(see picture on right); the anthocyanin was indentified as
cyanidin, this increase was a function of the concentration of
copper added. Another characteristic seen in some plants, was the
appearing of Agravitopic Gene, this gene inhibits the plant
response to gravity.
http://www.orst.edu/dept/lpi/ss01/anthocyanin.html
Over 300 structurally distinct anthocyanins have been identified
in nature.
http://www.agsci.ubc.ca/courses/fnh/410/colour/3_24.htm
Anthocyanins are widely distributed in plants, and are responsible
for the pink, red, purple and blue hues seen in many
flowers, fruits and vegetables. They are water soluble flavonoid
(C15H10O2) derivatives and phenolic (related to phenol, C6H5OH),
which can be glycosylated and acylated.
Anthocyanins & Metals: Coordination complexes
Some metals, such as Fe+3 and Al+3 form deeply coloured
coordination complexes with anthocyanins that have
ortho-dihydroxy groups on the B-ring. The effect of ferrous
ammonium sulfate on the colour...
Effect of Heat on Anthocyanins
Anthocyanins are sensitive to thermal processes, yielding a loss
in the desirable hue and an increase in a brown hue as
the pigment degrades and polymerizes.
http://www.carnivorousplants.org/cpn/samples/Science273anthocyanin.htm
The pigments absorb strongly in the UV (ultraviolet) and
anthocyanin-related pigments serve is as a protective UV screen.
The pigments are produced in response to UV exposure, and protect
the plant's DNA from damage by sunlight.
Environmental factors affecting anthocyanin production include
light (intensity and wavelength, with blue and UV being most
effective), temperature, water and carbohydrate levels, and the
concentrations of the elements nitrogen, phosphorous and boron in
the growth medium. Anthocyanin production can be induced by light,
blue being the most effective color.
http://www.gramene.org/newsletters/rice_genetics/rgn13/v13p25.html
Reddy et al. (1994) identified cyanidin and peonidin as a major
and minor pigments of anthocyanin, respectively, and suggested
that UV-B irradiation activates Pl^w, resulting in anthocyanin
induction. They also demonstrated that UV-B-triggered anthocyanin
induction is reduced by a terminal far-red light pulse and is
recovered by a red light pulse.
http://www.ag.uiuc.edu/~robsond/solutions/horticulture/docs/anthocy.html
Anthocyanin production also increases as phosphates moves out of
the leaves.
>Available light and nutrients surely play a role also but a search on the
>terms "temperature anthocyanin orchid" on goggle.com will lead you to more
>info than you really want. Substitute the word "Nutrient" for temperature
>in the above search string and you might even find a page that explains how
>nutrient changes effected anthocyanin pigment production in specific
>hybrid/species used in specific studies. You might also find a lot of
>unrelated do-do.
>
>Age of the tissue plays a role. Many flowers fade as they age. Buds are
>frequently much darker than fully open flowers because a fixed amount of
>pigment is diluted in the cells as they expand with water as they open.
>Different plants of the same species will show pigment variation, of course.
>One may be dark purple, and the other light pink.
>
>"Larry Dighera" <LDig...@att.net> wrote in message
>news:uouqku8pvk7v4lpde...@news-server.socal.rr.com...
Larry Dighera
Without modifying any other cultural variables, the addition of 1/4
teaspoon of 48% aluminum sulfate per gallon of water, returned my
pale-pink Epidendrum elongatum flowers to their true vibrant violet
hue within about a month. So, one could conclude that anthocyanin
color expression may be affected similarly by cultural variables
(temperature, pH, available aluminum, NPK level, available phosphorus,
UV-B radiation, ...) in orchids as it is in hydrangea.
On Mon, 12 Aug 2002 01:21:24 GMT, Larry Dighera <LDig...@att.net>
(Larry Dighera) wrote in Message ID
<0nudlu8vnt5mob7gb...@news-server.socal.rr.com>:
Ray @ First Rays Orchids
of your study, controls, etc. We had a war here over stuff like that a few
years back.
--
Ray Barkalow <> First Rays Orchids
http://www.firstrays.com
Secure Online Ordering & Lots of Free Info!
"Larry Dighera" <LDig...@att.net> wrote in message
news:rvgkpuk43ent6365r...@news-server.socal.rr.com...
Larry Dighera
>Be prepared for questions about the scientific basis
>of your study, controls, etc. We had a war here over stuff like that a few
>years back.
Ha. Ha. Controls? We don't need no stinkn' controls! :-)
Seriously though, the addition of aluminum sulfate did restore the
flower color to its "correct" state.