Somatic Embryogenesis Lab
Welcome to our Laboratory
Here at Maelor we have a state of the art laboratory complete with laminar airflow hood, autoclave, ultra-low freezers, liquid nitrogen facility etc. It was established with the help of world renowned Tissue Culturist and Tree Breeding expert Dr David Thompson with the aim of producing thousands of stock plants for VP production from a single embryo/seed using a process called somatic embryogenesis (SE).
Somatic Embryogenesis Overview.pdf
What is somatic embryogenesis?
Somatic embryogenesis (SE) is the process of deriving an embryo from somatic cells. This process mimics the natural processes that occur in development of seeds in the cones of a tree, however, somatic embryos do not contain seed coats or endosperms like zygotic embryos and the process is carried out in the controlled settings of a laboratory.
Why are we doing somatic embryogenesis?
SE is a desirable tool in forestry as it allows the large-scale propagation of genetically identical plants without the troubles associated with cuttings and seeds. Trees taken from seed lack uniformity as each seed is genetically distinct and one seed will only produce one tree. Somatic embryogenesis uses just one seed to produce thousands and potentially millions of genetically identical emblings. All of the processes in SE are carried out in the sterile environment of the laboratory.
With the development of technology and bioreactors there is also the possibility of complete automation of the process to further increase efficiency, yield and cost effectiveness. SE derived stock plants are juvenile so cuttings taken from them have less tendency to develop plagiotropism unlike cuttings taken from traditional stock hedges. Another application of SE is creation of hybrid spruces with unique genetics and characteristics. These can be tested in forest trials to identify plants which have gained traits that allow them to grow more ably in challenging environments. For example, plants that can grow in areas with dryer soil are selected with a view to developing plants that can withstand the pressures of climate change. It has been observed in the lab at the cell stage that these hybrids may exhibit heterosis (hybrid vigour) with embryos taking 3-4 weeks fewer to initiate when compared to their full sibling Sitka counterparts. This phenomenon can also be observed at every stage of development with hybrids consistently forming better plant structures more quickly.
How does Somatic embryogenesis work?
SE is made up of four main processes initiation/multiplication, maturation/development, desiccation/ germination and acclimatisation.
Initiation/Multiplication- In this stage seeds are removed from cones sterilised and their embryo’s excised and placed onto initiation media until embryonic suspensor mass (ESM) develops. Once this mass develops the material is sub-cultured onto fresh media and cell lines are established. These cell lines are sub cultured onto fresh media every 2 weeks to “multiply” the material. It is at this stage material can be taken for storage by cryopreservation.
(Cryopreservation- It can be many years before plants grown from SE exhibit any observable phenotypes in forestry trials. This means by the time cell lines with favourable characteristics have been identified the cell cultures from which they were made will have senesced and died. However, freezing cell lines can overcome this dilemma so that they can be regenerated at any future point.)
Maturation/Development- Once enough material has been generated the ESM is suspended in media and a thin layer is spread onto filter paper on black development/maturation media. This media contains activated charcoal and abscissic acid to encourage the development of mature embryos.
Desiccation/Germination- From the mature embryos ones with good cotyledon formation are selected and are plated onto a petri dish within a larger petri dish filled with water. After 3 weeks of this desiccation the embryos are plated onto germination media and left to form roots and shoots.
Acclimatisation- Once the emblings have developed adequately they are ready to be transplanted into soil. After transplanting the emblings are kept at high humidity and carefully monitored for pest and diseases and gradually brought to ambient conditions.
What other work do we do?
Although somatic embryogenesis of Sitka is the main focus of the lab we also carry out this process on larch, oak, ash, pine and sycamore. Work is also going into organogenesis of oak and ash buds. Organogenesis is the induction of plant organs such as meristems, leaves, roots, flowers and vascular system to form plantlets.
As well as our SE facility, we also have an FC certified Seed Testing Facility for testing purity, viability and germination of seeds. In addition to this we are Associate Members of International Seed Testing Association (ISTA).