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The 'Christmassy' killer raspberry

Wolfgang Stuppy
11 December 2012

The Millennium Seed Bank's seed morphologist, Wolfgang Stuppy, is back with his final blog of the year. To wish you all a very 'Merry Christmas', he is sharing some festive images of a flesh-eating killer raspberry! Do you dare read on ...

Merry Christmas!

Since this will be my last blog for 2012, here comes a heartfelt ‘Merry Christmas’ to everyone, with a festive photograph of a fruit that looks like a raspberry. It actually shows a close relative of the raspberry (Rubus idaeus and hybrids thereof) called Japanese wineberry (Rubus phoenicolasius).
 

SEM picture of a Japanese wineberry

Japanese wineberry (Rubus phoenicolasius). [Image from ‘FRUIT – Edible, Inedible, Incredible’ by Wolfgang Stuppy & Rob Kesseler; Copyright Papadakis Publisher, Newbury, UK] 

A flesh-eating killer raspberry

Edible and tasty, although not as delicious as a real raspberry, this native of northern China, Korea and Japan is sold by nurseries in the UK and grown by some people in their gardens. Unlike a regular raspberry, the calyx surrounding the fruit of a Japanese wineberry, is covered in sticky glandular hairs, similar to those found in carnivorous plants such as sundews (Drosera spp.). This has led some people to assume that Rubus phoenicolasius might actually be a carnivorous raspberry. A flesh-eating killer-raspberry? Sensational!

Calyx surrounding Japanese wineberry and the glandular hairs of sundew

The calyx that surrounds a Japanese wineberry (left) is covered in glandular hairs which are very similar to those of carnivorous sundews, Drosera capensis (right). (Photos: Wolfgang Stuppy) 

Really?

Well, not quite. A thorough scientific investigation in 2009 (pdf) has busted this myth. Although the glandular hairs of a Japanese wineberry contain tannins that help ward off herbivores, the mucilage they secrete does not contain any digestive enzymes and neither are the hairs capable of taking up any potential solutes. The sticky hairs on the calyx are mainly there to protect the bud from insect predation but not to kill and devour any creatures - although very small insects may become trapped and die. 

The making of ...

Returning to the actual picture of the fruit shown at the beginning, you will have noticed that this is not a straight ‘shot’ with a regular camera. In fact, the image is taken with a Scanning Electron Microscope (SEM), a very expensive device that uses an electron beam instead of light to scan and visualise objects.

 

SEM at Kew's Jodrell Laboratory

One of Kew’s Scanning Electron Microscopes at the Jodrell Laboratory (photo: Wolfgang Stuppy)

The advantage of an electron beam is that it has a much shorter wavelength than light. As a consequence, the resulting image has much greater depth of field and resolution, giving it a hyper-realistic look. The only disadvantage is that an electron beam has no ‘colour’ and so the resulting image comes in black-and-white only. To ‘spice-up’ the very ‘sciency’ monochromatic appearance of SEM pictures, I have teamed up with artist Rob Kesseler. Our fruitful (excuse the pun) collaboration started in 2005 and since then we’ve done quite a few crazy things in the lab which no respectable scientist would ever do. One was shuffling a whole Japanese wineberry into the vacuum chamber of a Scanning Electron Microscope.

 

Japanese wineberry with platinum coating

Our specimen of a Japanese wineberry covered in a fine layer of platinum as a preparation for observation in the Scanning Electron Microscope (photo: Wolfgang Stuppy)

A microscope, not a macroscope!

As its name implies, a Scanning Electron Microscope is an instrument with which to magnify very small things to make them visible. At a diameter of about 2 cm, a Japanese wineberry isn’t exactly something you need a microscope to look at. So when we decided that an SEM ‘photograph’ of this fruit would look very ‘cool’, it was no surprise to discover that it was far too big to fit into the SEM’s field of view. Determined to succeed, we were forced to take 56 individual images which Rob then had to painstakingly stitch together into one. The rest is history.

 

Japanese wineberry SEM image jigsaw reconstruction

The beginning of the jigsaw-reconstruction of the Japanese wineberry from 56 individual SEM photographs (image: Wolfgang Stuppy & Rob Kesseler)

Many thanks to everyone who has followed my blog so far and for the encouraging feedback. I know now that although I am probably the only Seed Morphologist in the village, I am surely not the only person who believes that seeds are amazing!

 

Floscopa glomerata seed dressed as santa

The seed of Floscopa glomerata, a member of the spiderwort family (Commelinaceae) from Mali, dressed up as Santa Claus. [Seed image from ‘SEEDS – Time Capsules of Life’ by Rob Kesseler & Wolfgang Stuppy; Copyright Papadakis Publisher, Newbury, UK; Santa hat design: Gemma Toothill]

- Wolfgang -


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Comments

13 April 2013
Comment: 
After reading this, I'll have to look very closely at the killer raspberry that comes with my next slice o' cake...
10 January 2013
Comment: 
Terrific post Wolfgang! I just received a copy of "Seeds Time Capsules of Life" for Christmas. Extraordinary ! The type is very difficult to read - wish I had access to the original copy so I could read it enlarged online. Thank you for your great work.
3 January 2013
Comment: 
Great post Wolfgang! Looking forward to reading a lot more of these in 2013! Happy New Year to all at Kew.
17 December 2012
Comment: 
Great post thanks Wolfgang! I especially like the close-up of the Japanese wineberry. It looks like a raspberry shaped star!
Abuse Reported. Comment will be reviewed and removed if necessary.
14 December 2012
Comment: 
Thank you for your comment. Our blogs are written by different experts behind the scenes at Kew and provide a unique insight into the work that goes on here, in particular our vital science and conservation work which is often out of public view. As well as providing unique access to expert knowledge and insight, each blog is written in a different style and tone, staying true to the authors voice and personality. This personal touch is one of the reasons that we think our blogs are so popular with audiences and read by thousands each week.
10 December 2012
Comment: 
Oh dear, what has Kew come to? I'll let you get away with 'Christmassy' (though surely with a capital 'C'?) but 'sciency'? And as for that seed image looking like a clip art Father Christmas? And I won't even start on the spelling and grammar mistakes (its, morpholgical ...)

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