I was inspired to do a Google search on stigmas, since I have observed stigmas that are two parts (typical ), three parts (unusual, and makes me think triploid genetics), four parts ( never seen this before today), and fused stigmas. Well, the first search hits didn't get me what I wanted, but instead I came across a June 2020 research paper that although was not done on dahlias, I think would apply to dahlias. The study investigated the affect of heat stress on pollen and pollination. One conclusion in the paper that's of interest to me, and I think has been mentioned before in this forum states:
Taken together these results indicate that heat stress negatively impacts on pollen attachment to stigma as well as pollen viability.
I am now thinking of ways to reduce the heat stress on Dahlia buds that I want to use for pollination. I might be able to conclude that cut flowers brought inside a cool house would produce pollen more viable than pollen on a flower left in the heat.
To further conclude... Maybe I shouldn't be hand pollinating on days around 90 degrees. 😅
