I have stored Bromeliad pollen. Best dried with silica gel and then frozen it should keep at least a few months. Dried and refrigerated it will keep a few days, just stored at room temperature it loses its viability very quickly.
It needs to be brought to room temperature still sealed otherwise water will condense on the pollen and render it unusable
Mammillaria, Echinopsis, Gymnocalycium, Matucana, Turbinicarpus pollen collected on cotton wool bud sticks wrapped in aluminium foil and in an airtight container will last for 4 to 5 months in a fridge
Endeavouring to grow Aylostera, Echinocereus, Echinopsis, Gymnocalycium, Matucana, Rebutia, and Sulcorebutia. Fallen out of love with Lithops and aggravated by Aeoniums.
Currently being wooed by Haworthia, attempting hybridisation, and enticed by Mesembs.
From my readings of it, basically Calcium Chloride flakes to dry (so they don't dry the pollen too much) in a sealed container for two hours or overnight. Seal in an airtight container before freezing.
Before use defrost (by holding the container in your hand for 5 minutes) and then place in 75% humidity for 1-2 hours before use.
ta. Not that long, really. I don't have calcium chloride but I do have silica gel Anyway, we'll see. it was my aim to use the Aloe mutabilis pollen on Aloiampelos striatula flowers but I am not sure I'll get any this year as all the stems on nearly all my plants have been frosted!
To preserve pollen by freezing you need to remove sufficient moisture so that Ice crystals are unable to form. All pollen will behave differently when dried so if you were to equilibrate a selection of pollen to a particular relative humidity they would probably have different amounts of residual moisture.
One way to realise a particular % RH is to use a binary salt solution, that is the salt and water in equilibrium in a sealed container, Its so reliable, it can be used to check the calibration of humidity meters. I chose calcium chloride because it was readily available and 'cheap as chips' This is what I used https://www.kilrock.co.uk/product/damp- ... kg-refill/ and Wilco had it in stock at the time. To get it into the right state just expose a sample to the air for a short while until the flakes appear to be wet, then put it into a sealed container.
Silica gel is great if you want to dry something down to 5% RH or less to preserve it. It would need to be freshly dried in the oven (105-120 °C for a couple of hours). If you were to dry pollen using fresh silica gel it would most likely remove too much moisture and kill it. The second problem with silica gel is that as it absorbs moisture the equilibrium RH will increase and without an accurate humidity meter you won't really know what you've got. The self indicating gels transition colour at quite a low RH. This is one of the properties that curators use to preserve museum exhibits in sealed cases. They use a large excess of silica gel that has been stabilised at the %RH that they need. https://www.musecc.com/silica-gel
Anyway, we'll see. it was my aim to use the Aloe mutabilis pollen on Aloiampelos striatula flowers but I am not sure I'll get any this year as all the stems on nearly all my plants have been frosted! 