Wednesday 20 March 2013

The growing mediums


The Growing Mediums 

As it was mentioned in the chapter "A little bit of Orchid science", orchids need fungi to help them grow. How does this work? Well there have been numerous research projects conducted to try and find a way of propagating orchids without needing the fungus. They have all used AGAR, a gelatinous substance with the specific nutrients and growth hormones needed for each plant to grow. It doesn't just work with orchids, there are many plants that can be propagated this way in a lab. The two being used are Mirushage & Skoog and F522. 

Mirushage & Skoog (MS) 

This growing medium was invented by Toshio Muragishe and Folke K Skoog in 1962. This happened during Murashige's extensive research to find a new plant growth regulator. The mix can be modified to suit the plant being grown. Some research undergone has shown that it is not a recomended medium for orchid growth but can be used, (J. Arditti,2008).
The standard mix found in MS medium are the following essential plant nutrients:
- Potassium
- Calcium
- Carbon
- Nitrogen
- Magnesium

and many more. These of course change depending on the plant.( R. Trigiano & Gray. D, 2010) 

The medium F522

An american company called Phto- technology Laboratories  have developed a growing medium specifically for terrestrial orchids such as the genus Dactylorhiza. It is a sucrose and Fructose specific medium that also contains the gelling agent that allows to solidify. In the mix we must also include the growth hormones needed to stimulate shoot and root growth (this replaces the fungi), (Phyto technology labroratories, 2011). The growth hormones that are present are cytokinin and auxin. The Cytokinin is what stimulates cell division, a hormone that can be found through natural sources. Auxin is what stimulates root and shoot growth after germination. (A. Perrara, 2012).
These growth hormones can be found in all types of growing mediums but they can change depending on the stage of growth. 

The BIG question

So the whole Dissertation is about this on question:

On what growing medium will the Dactylorhiza seeds have a better germination rate?

My hypothesis is that they there will be a better success of germination on the Phyto technology Laboratories F522 medium. This is because it has been produced after a number of years of research and has the necessary food source for the orchid's embryo to absorb! 

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