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Processing

Depending on what we know about the biology of the species, seeds might be processed straight away and deposited into the seedbank. Others might need to be tested for their response to drying before we can store them appropriately.

Seeds returned to PlantBank usually need some post-collection processing to ensure we have a good quality, clean collection that is ready for research, transport or storage. If we are unsure of the most appropriate conditions for seeds to be stored, a subset will be tested, while the bulk of the collection remains in temporary storage. 

Processing fleshy fruits

Rainforest species often have fleshy fruits, so there are a number of different techniques we can try to remove the flesh without damaging the seeds.

Flesh removal techniques

By hand
Quite often the flesh of rainforest seeds are soft and therefore easy enough to remove by hand.
Sieve
By pressing fruit into a metal sieve, the flesh is pulled away from the seed. The fruit is usually rolled around in the sieve to remove the flesh from the entire seed surface. This approach is particularly useful if the flesh has dried and become quite rubbery and resistant. 
Scourer
By placing fleshy fruits between two ribbed rubber paddles and sliding them over each other, the friction created between the paddles gently pulls the flesh away from the seeds. This technique is great for small seeds with soft flesh.
Digestive enzymes
Much like the enzymes we have in our stomachs that break down food, we can use enzymes in the lab to dissolve the flesh off rainforest fruit. This process has to be managed carefully so that the enzymes do not damage the seed itself, but because seeds naturally pass through the gut of animals, many have tough coats which provide natural protection. 

Processing hard seeds

In other circumstances rainforest seeds are in a hard covering or within a hard capsule that needs to be cracked open to extract the seeds. Depending on the nature of the covering, one of the following techniques may be applied. 

Seed extraction techniques

Crushing
Sometimes a bit of force is required to separate the seed from the seed coat. By simultaneously crushing and rubbing seeds together we can crack the seed coat and 'roll' the seeds out. This is only possible with seeds that are quite hard to ensure that no damage occurs. 
Dry heat or desiccation
Many Australian plants are adapted to only release their seeds after being exposed to very high temperatures, which would naturally occur during a bush fire or during warmer temperatures. Sometimes we have to replicate these high temperatures in the lab which may involve flaming seed capsules to open them. Other seeds may however simply need a few hours or days exposure to warm air which dries the capsule causing it to shrink. For some rainforest species, this results in the explosive release of seeds from the capsule as the segments are forced apart. 
Excision
Seed capsules are often tough to protect the soft seed that is within - this means that seed damage is likely during cleaning. For a more precise approach, seeds can be carefully cut from capsules by hand either using a scalpel, hand saw or even a power saw or drill. For large collections this can takes a very long time!

Final cleaning to remove debris

Once seeds have been released, a final round of cleaning may be required to remove any debris - frass (insect droppings), leaves, twigs, dust etc - that will reduce the quality of the collection. Two simple ways this can be done include separating seeds by their size through a series of sieves, or by weight, in which case seeds are passed through an air current that 'blows' away the rubbish, allowing the heavier seeds to drop into a collection container. Larger debris may also be removed by hand.

Once the collection contains pure seeds, it’s time to package the seeds up ready for transport or storage. However, if we don't know the best way to store the seeds, then this is the time to start testing.