Dendrobium nobile changing colors?

[Yen]

Hi everybody!
I started researching and experimenting with den nobile and I'm hoping if someone can answer me this question...

So I've been googling/youtubing den spring dream apollon and some other white den nobile... I noticed that some people's spring dream apollons would have a tinge of pink to the petals/sepals of their orchids in one year but would be completely white another year... why is that? Does it have to do with genetics or simply external factors like temp/humidity/watering/etc...?

Thanks!!

[Ray]

Possibly genetics and cultural parameters. Bright and cool favors the development of red pigments, for example.

[DirtyCoconuts]

I’ll be able to add photos tomorrow or Wednesday but most my nobles have different colors among the same plant and even more on divided keikis mounted in different spots

[DirtyCoconuts]

these are my two lager colonies and they are opening at different times and in slightly different places- they were both wintering in the lath house and then moved to the patio (my wifes desk) for the flowering- the buds on the right are the newer ones

Cats on the....grow by J Solo, on Flickr

here on the mellow mind, the older flowers have the pink hues

Nobles by J Solo, on Flickr

while the newer one are all yellow
Nobles by J Solo, on Flickr

[Roberta]

I have noticed with hybrids of several groups, that when pink ancestors gets mixed with yellow ones, the pigments tend to develop at different times (and in different proportions) depending on such things as light and temperature probably, as well as time, so you get some very interesting surprises. Neat!

[DirtyCoconuts]

this shows the whole second colony and you can see the variation

Nobles by J Solo, on Flickr

[camille1585]

That's super cool to see the variation on a single plant!! I love the color changing flowers, and it's always the red/yellow color combinations that are likely to do this. I have a Phal which starts out very reddish and then fades to a bronze color as the flower ages.

[Roberta]

Paph Armeni White is interesting to watch... it's P. armeniacum (intense chrome yellow) with P. delenatii (pink). It opens pale yellow, then as the flower matures becomes very white.
http://orchidcentral.org/Images/Paph...t%20opened.jpg
http://orchidcentral.org/Images/Paph...ni%20White.jpg

And here is Blc. Zul with both new and mature flowers http://orchidcentral.org/Images/Catt..._Blc%20Zul.jpg