The Germination capacity of stored pollen.

[Rob]

The Germination capacity of stored pollen, from this paper is probably not what you may have expected, especially when we look at this table below. The pdf of the study, is below the table.

Screenshot 2026-04-28 at 17-00-21 Germination capacity of stored pollen of Ficus carica (Moraceae) and their maintenance - Khan &amp Perveen Pak.J.Bot. (2008).pdf.png

[Rob]

I should have pointed out that pollen on it's own will not germinate, it needs to be inside of a fig, in a sugar solution, or in this case sugar and boric acid solution to begin to grow. When it does grow, the pollen grains look like they are growing arms, and once there is any sign of the pollen tube growing, it is considered germinated. Of course all this is only seen under a microscope.

[Rob]

This is not pollen from a caprifig, but it is pollen, and I will try to germinate my own here over the next few days to show here, but here the dark balls are the pollen grains viewed under a microscope, and the small lighter arm like parts are the pollen tubes, showing that many grains have in fact germinated. As the pollen germinates further, the arm like tubes grow much longer. In our figs, the female flowers, short or long styles, have secretions that prompts pollen growth, with or without sugar added to the pollen and water mix for hand pollination.

[Rob]

In Saleeb's 1965 paper, he shows us this picture of fig pollen growing pollen tubes. He also mentions that Condit stated, "0viposition by Blastophaga injures the cells of the stylar canal producing a toxic effect which inhibits growth of the pollen tubes", and this is why a fig seed cannot grow once the flower has had an egg inserted into it..

GENETICS AND CYTOLOGY OF SYCONIUM PERSISTENCE - Saleeb 1965_dissertation.pdf.png

[epiphyte]

ooooo, hmm. i was under the impression that the developing seed is exactly what the larvae eat!

[Rob]

Ah, the way it seems to work is, once the flower has an egg inserted, and even if the wasp happens to drop a few pollen grains onto the stigma, it will take a number of hours for pollen grains germinate and for pollen tubes to grow enough to fertilize the seed in the flower...so the egg wins. Condit was incorrect in his assumption, regarding the toxic effect in the stylar canal according to Neeman and Galil below, but something clearly prevents the pollen tube from fertilizing the seed once the egg is there. I will read further on this, but from my memory, the larvae does consume the unfertilized seed though.

Screenshot 2026-07-29 at 13-13-47 Neeman1978.pdf.png

The pdf of the complete study is here...

Neeman1978.pdf

[Rob]

This is from a study by Finn Kjellberg and Emmanuelle Jousselin, and I am guessing Finn was the one in France submitting the data on carica, and carica of course is passively pollinated. The complete article is here, along with the paragraph that mentions that "most pollinators of carica, will develop in unfertilized flowers", and "they are true ovule gallers"..... So the wasp larvae do not need to feed on the fertilized seed to grow.

Screenshot 2026-07-30 at 11-39-00 Jousselin2001EL.pdf.png

Jousselin2001EL.pdf