thanks for the info. the silica gel I have is not telltale with a moisture indicator dye. now that makes sense. I guess we could use for storing maize pollen as well. thanks for your input

Lebo

I usually use silica gel to collect for far distances, and I use a normal "soup spoon" to add the silica in the zipplock bag (apron 4x6cm) I put the leaves inside the bag (like 500mg) and in another bag to transport them to the Lab. My field work is for like 5 days, I don't change the silica until I get to the Lab (and if the silica didn't change the color, I don't change the silica). Normally I keep the samples in a box (at room temperature like 70-80ºF). :)

But test the exact method you will use first. Some plant leaves are perfectly fine this way, but for others for example a lot of Proteaceae in my experience the DNA degrades rapidly long before the leaf dries. For those it's necessary to cut the leaf in pieces and stick the tissue in 1.5 or 2ml tubes of saturated solution of CTAB instead of silica gel.

Thank you all for your inputs

Any suggestion to store leaves for 2 weeks of field work?

Andrew, do I store the leaves in concentrated CTAB in a freeze i.e. -4 C? 

Along with that, after the silica has changed colour and the leaves have dried, can I store the leaves without silica gel? 

Hey you all,

I have used silica gel in bulk, 100 lbs. or so, but, it is contaminated with trace amounts of old, very tiny plant fragments. Do you see a problem using this recharged silica for samples in permanent storage in a freezer? I was thinking to use it with samples that are sealed in those 2-inch manila envelopes anbd hen sealed inside platic bags containing the used silica.

@ Eric Feltz,

I don't see a problem, as long as the contaminated samll trace amount of old tissue don't accidentally get into the envolopes which have your new plant tissues. The mixture of the contaminated old tissue with your new tissue might give you unexpected experiment results (ex. PCR).

Use paper bags to separate the plants from the silica gel crystals! to make ensure it will not be mechanically crushed. The zip lock (thick plastic bag) will serve in very low humidity penetration. Just make sure that you will replace the silica gel after a couple hours, for quick drying!

If new silica gel is separated from leaf samples by putting the leaf samples in teabags, can the silica gel be dried afterwards and used again to dry new leaf samples without contaminating DNA? Similarly, can samples from separate plants (each in separate teabags) be stored in the same container in a freezer? My research question is about introgression so I am cautious about DNA contamination but also (of course) short of money and freezer space.

See this link:

https://www.thermofisher.com/in/en/home/references/protocols/nucleic-acid-purification-and-analysis/rna-protocol/genomic-dna-preparation-from-rnalater-preserved-tissues.html