Bewdley Orchids
  • Home
  • About us
  • Plants for sale at talks
  • Looking after your orchid
  • Seed cultivation
  • Contact page
    • Payment by cheque
  • Talks
  • Orchid blog from Bewdley
  • Orchid Gallery
    • Frost sensitive orchids

the question of spotty leaves

19/1/2017

1 Comment

 
Picture
Early Purple Orchid seedling in sterile culture at 15 months old.
This picture is interesting for many reasons. The first is that the photograph shows a considerable amount of spherical aberration. This is a physical phenomenon associated with lenses which have flaws resulting in different focus points. This is different to depth of field and has more in common with chromatic aberration, where the different point of focus varies with the wavelength of light.

In this case it is not some strange home made lens that has caused this affect, it is photographing through the side of a glass jar which has caused this odd result. The plant is really very small, 2cm from base to tip and some distance from the side of the jar. This is not the most interesting thing, however. It is the spotting. This has developed after one year in sterile culture, starting as surface sterilised seed, with one sub-culturing event. This development of spotting in Early Purple Orchids, Orchis mascula, is quite common which makes me think that it is most likely not viral in origin. Well, not unless it is a viral infection present in the seed. There are ways to test for virus activity which are easy to carry out as confirmation, which we may do later in the year just as a matter of curiosity.

What is really rather more interesting a question is what controls the expression of spotting. Individual plants will always maintain the same amount of spotting, a very spotty plant will always be very spotty and a relatively lightly spotted plant will always be lightly spotted. What differs is the distribution of spots.

There is another aspect of spotting which has a certain intrigue and that is the disappearance of spots later in the season.

All these questions, all of which can be answered given a little ingenuity and a supply of plants. So far we have only started to look at pattern development in Common Spotted Orchids, Dactylorhiza fuchsii. These are very tolerant plants that are easy to grow and since they live for a long time we get several years of measurements from each plant.

1 Comment
richard
5/2/2017 01:50:17 pm

would you mind telling me which native british orchids are winter green please

Reply



Leave a Reply.

    Author

    Dr Wilson Wall, grower of orchids. A scientist by inclination and training.

    Archives

    May 2020
    May 2018
    April 2018
    February 2018
    November 2017
    September 2017
    July 2017
    June 2017
    May 2017
    March 2017
    January 2017
    November 2016
    October 2016
    September 2016
    August 2016
    July 2016
    June 2016
    May 2016
    April 2016
    March 2016
    February 2016
    January 2016
    November 2015
    October 2015
    September 2015
    August 2015
    July 2015
    June 2015
    May 2015
    April 2015

    Categories

    All

    RSS Feed

Website content  © Bewdley Orchids 2019
Proudly powered by Weebly