PacMan Pollen

[Baley]

We've had a lot of pollen in the air lately so I took a slide outside for about an hour, put some glycerine-water on it, covered, and had a look. As I was looking at this stalk I noticed the pod was blowing a bubble. Is this pollen?
22x Ultropak

40x Leitz APO

[BJ]

Hi Baley,

an interesting photo!

Firstly, I think that the filament and the pakman are not connected. The filament might just be a stray cotton fibre.

I think that pakman is indeed a pollen grain and I think is pollen from a cypress (Cupressus sp) or related tree (NB I am not an expert on this). Pollen has two wall layers; an outer sculptured "exine" and an inner smooth "intine". Normally pollen germinates by producing a tube through a pore in the wall.
(see here for example: http://www.sciencephoto.com/media/32951/view )

Cypress pollen is unusual as it germinates by taking up water and the intine-bound pollen bursting out - as per your pakman. The process is described and illustrated here: http://aob.oxfordjournals.org/content/e ... 4.full.pdf

There is a clear space between the intine and the membrane surrounding the cytoplasm - and presumably as water is taken up into this space, the pressure builds up and eventually bursts the exine.


thanks for posting !

Brian

[Baley]

Brian,
Thanks for that explanation and link. You are correct that the pod and stalk are not related - I found several other pods with intines nearby in other areas of the slide. We do have a lot of cypress here and I appreciate your ID.