Beet Juice & Pollen - maybe

[Baley]

I just set up my Ortholux for POL having made one filter from some plastic POL sheets used to test stress in glass, and using another glass filter over the field lens. So I began looking at things. I dried some juice from a bottle of Felix beets and found some interesting effects. The granules were green in brightfield but showed structure in XN. Beet crystals? Later I examined a slide that I had left outside for a few hours to collect pollen and found something that looks somewhat similar. There was no beet juice on this slide. I thought this was very strange since in normal light the objects do not look like pollen and they look remarkably like the beet juice specimens. Comments or suggestions are welcome. Slide #1 was 25x phaco brightfield, #2 63x Phaco brightfield. I don't have any POL objectives yet.

[gpmatthews]

These look like starch grains. In polarised light the dark cross is characteristic and is centred on the hilum of the grain. You can see the hilum as a dark spot in the brightfield images.

Try looking at wheat flour, corn flour, washings from rice and potato. You should see similar grains. Starch from different sources has different appearances - an interesting field for comparisons.

Starch gets everywhere - very easy to get cross-contamination. A very common source of contamination is dusting powder from inside rubber gloves, for example - and of course is found in roots, rhizomes etc., such as beet.

[Baley]

Thanks for that explanation. They certainly do not look like crystals. I'll do as you say with starch and report back.