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Corymbia maculata [Spotted Gum]

Fluorescence
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#1 DaveO

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Posted 25 June 2015 - 06:18

Oldfield, D. 2015. Corymbia maculata (Hook.) K D Hill & L A S Johnson (Myrtaceae) Spotted Gum Flowers photographed in visible and ultraviolet light.
http://www.ultraviol...ta-spotted-gum/
Synonyms
Eucalyptus maculata Hook.

Maldon, Victoria, Australia
23 June 2015
Australian Native Wildflower as Garden Specimen

Comment
Corymbia maculata was one of around 80 eucalypts transferred in 1995 to the newly created genus Corymbia. A corymb inflorescence has the appearance of a compound umbel, however it has irregularly lengthened pedicels that help form a flat-topped inflorescence. It is a widely distributed species extending in a narrow coastal belt from south-eastern Queensland to southern New South Wales.

Flower buds of Corymbia and Eucalyptus species have a bud cap (operculum) which is often diagnostic for the species. Buds often have two opercula, with the thinner outer one shed early or late in bud development, causing a scar at the join with the bud base (hypanthium). It appears in this species that the rough greenish outer operculum is in the process of being shed on some buds to reveal the red inner operculum, which is itself then shed when the stamens open. The inner operculum appears to be red in visible light, black in UV and fluorescent blue in UVIVFL. A complete blue inner operculum can be seen in the UVIVFL image slightly left of centre front. The colouration may be due to the presence of anthocyanin pigments in the operculum.

Visible Light: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Metz 15 MS-1 flash, 1/200 s @ f/16 ISO 200, Baader UV/IR Cut Filter.
Attached Image: Corymbia_maculata_Vis.jpg
Image Reference: DO60508

Ultraviolet Light: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Nissin Di866 Mark II flash, 1/200s @ f/16 ISO 200, Baader UV-Pass Filter.
Attached Image: Corymbia_maculata_UV.jpg
Image Reference: DO60511

Ultraviolet Induced Visible Fluorescence: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens with Baader UV/IR Cut Filter, Nichia NCSU033A UV-LED with Baader UV-Pass Filter, 30.0 s @ f/16 ISO 400.
Attached Image: Corymbia_maculata_UVIVFL.jpg
Image Reference: DO60514

References:
Elliott, W.R. and Jones, D.L. Encyclopaedia of Australian Plants suitable for cultivation, Volume 4, 1986, Lothian, p. 139 [as Eucalyptus maculata].
French, M, Eucalypts of Western Australia’s Wheatbelt, 2012, Malcolm French, p. 17.

Published 25 June 2015

Edited by DaveO, 25 June 2015 - 06:19.


#2 nfoto

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Posted 25 June 2015 - 07:28

These signatures are so interesting. What has been known or published before of these features?

#3 DaveO

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Posted 25 June 2015 - 10:09

I'm busy searching at the moment, so any refs from any other members will be most welcome. I have already found a study on strawberries of all things which were photographed in visible, UV and UVIVFL conditions and, yes, there was blue fluorescence. (Breeding Science 63:211-217 (2013) doi:10.1270/jsbbs.63.211

I will now have to go looking at ALL eucalyptus flowers and buds, surely I can't have hit on the only one that did this!!!

When I was a working research chemist I was a great believer in serendipity, so I shall head off at this tangent at a rate of knots :(
Dave

#4 msubees

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Posted 25 June 2015 - 15:09

Beautiful blue color in the last one. Do you have to do it in total darkness to get this? Zach

#5 DaveO

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Posted 26 June 2015 - 00:13

Yes, I have a dark room set up so that I can take all three (Vis, UV, UVIVFL) shots one after the other. Taking a dark tent into the field is going to be much more difficult.

Dave

#6 msubees

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Posted 26 June 2015 - 02:51

Dave,

Thank you for the information.

Zach

View PostDaveO, on 26 June 2015 - 00:13, said:

Yes, I have a dark room set up so that I can take all three (Vis, UV, UVIVFL) shots one after the other. Taking a dark tent into the field is going to be much more difficult.

Dave


#7 DaveO

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Posted 01 July 2015 - 05:04

More images showing details of the inner bud cap (operculum).

The central bud has lost the outer bud cap but the inner one is still present. The operculum is strongly UV-absorbing and strongly fluorescent.

Visible Light: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Metz 15 MS-1 flash, 1/200 s @ f/16 ISO 200, Baader UV/IR Cut Filter.
Attached Image: Corymbia_maculata_buds_Vis.jpg
Image Reference: DO60544

Ultraviolet Light: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Nissin Di866 Mark II flash, 1/200s @ f/16 ISO 200, Baader UV-Pass Filter.
Attached Image: Corymbia_maculata_buds_UV.jpg
Image Reference: DO60547

Ultraviolet Induced Visible Fluorescence: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens with Baader UV/IR Cut Filter, Nichia NCSU033A UV-LED with Baader UV-Pass Filter, 30.0 s @ f/16 ISO 400.
Attached Image: Corymbia_maculata_buds_UVIVFL.jpg
Image Reference: DO60548

In this set the inner and outer bud caps are being lost together. You can see the edge of the inner bud cap and the stamens of the flower which are UV-dark and slightly fluorescent.

Visible Light: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Metz 15 MS-1 flash, 1/200 s @ f/16 ISO 200, Baader UV/IR Cut Filter.
Attached Image: Corymbia_maculata_bud_cap_loss_Vis.jpg
Image Reference: DO60551

Ultraviolet Light: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens, Nissin Di866 Mark II flash, 1/200s @ f/16 ISO 200, Baader UV-Pass Filter.
Attached Image: Corymbia_maculata_bud_cap_loss_UV.jpg
Image Reference: DO60553

Ultraviolet Induced Visible Fluorescence: Nikon D750 Full Spectrum Modification, Nikon Rayfact PF10545 MF-UV 105 mm f/4.5 lens with Baader UV/IR Cut Filter, Nichia NCSU033A UV-LED with Baader UV-Pass Filter, 30.0 s @ f/16 ISO 400.
Attached Image: Corymbia_maculata_bud_cap_loss_UVIVFL.jpg
Image Reference: DO60555

#8 colinbm

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Posted 01 July 2015 - 05:09

Beautiful Dave, I just love that half open bud, in UVIVF ;)
Col

#9 Andrea B.

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Posted 01 July 2015 - 14:32

This is just a spectacular example of UV-induced visible fluorescence !!!
Thank you, Dave, for the additional work on this one.

Isn't this an interesting surprise?! We never know what fascinating view we are going to discover with our UV eye.

It looks like that blue fluorescence is so strong that it is shining onto the stamens.
Andrea G. Blum
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#10 DaveO

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Posted 02 July 2015 - 00:51

My "chemist's nose" is leading me on this one, there has to be a chemical explanation for presence or absence of such strong fluorescence. A quick scan of other eucalypts suggests that there are not very many which clearly have two bud caps which shed at different times. Sometimes the outer operculum is shed very early and never found, others the two are fused together.

The term Eucalyptus refers to the bud cap, eu meaning well and calyptos meaning covered. The sepals fuse to form the outer cap and the petals fuse to form the inner cap, then often the inner and outer fuse together and shed as one. If the outer sheds first it leaves an "operculum scar" which often requires the "eye of faith" to see, but I'm not a botanist so I don't have those eyes ;)

Dave

#11 colinbm

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Posted 02 July 2015 - 02:11

"The term Eucalyptus refers to the bud cap, eu meaning well and calyptos meaning covered. The sepals fuse to form the outer cap and the petals fuse to form the inner cap, then often the inner and outer fuse together and shed as one. If the outer sheds first it leaves an "operculum scar" which often requires the "eye of faith" to see, but I'm not a botanist so I don't have those eyes"

Thanks Dave for the detailed explanations here, sometimes you need to stand back to see the forest from the leaves ;)
Col