​A recent addition to the collections at RBGE is the material which has been dried in silica to preserve the DNA for later extraction and sequencing. This technique is commonly used for plant material thanks to its effectiveness in preserving the DNA, ease of use in the field and low cost.

Preservation method

Originally, leaf material was chosen and placed into a bag with direct contact to the silica gel granules. The granules would often comprise a mix of standard silica granules and a certain amount of indicator granules which will change colour depending on the water taken up.

A more recent method uses empty teabags such as those available to buy in supermarkets. The plant material is placed into the empty teabag which is then placed into a container of silica. The silica can then be more easily replaced when it becomes hydrated and the plant material is easier to handle.

The scope of the silica-dried collection

The silica-dried collection is extensive and is growing rapidly each year as more collectors will routinely collect material in silica. Whilst most of the silica-dried collections are linked to a voucher herbarium specimen, there are large collections from population studies and plot sampling which have a smaller number of representative voucher specimens.

There are large silica-dried collections for our key focus groups, as well as for a range of research projects which have been undertaken at RBGE. We are now working to catalogue these collections and link them to the main herbarium and other molecular collections.

Use of the collection

The collection is well used by research staff. Where possible, these collections are also used for destructive sampling requests rather than the herbarium specimens.