This image is of pollen from a Rosa ‘Iceberg’ flower. The image shows pollen shaped like seeds and colors varying between dark brown and golden. The golden color is possibly due to nectar mixing with the pollen or it could be the natural color of the pollen. The pollen is clumped together in the center of the photo (in focus). It is worth noting that while the average shape of the pollen is “seed”-like, some of the pollen is close to circular and some of the pollen is quite elongated.

The sample of pollen shown above was obtained at 5:44 pm on Wednesday, May 8th, 2019. The flower (from which the pollen was obtained) was obtained from the California Institute of Technology- specifically from a bed of flowers in front of the Center for Student Services. The address for this location is 414 S. Holliston Avenue in Pasadena, California (91125). The flower bed where the flower was collected is shown below:

To obtain this sample, a glass slide was rubbed against the anthers of a flower from the flower bed (the specific flower is shown below) to let pollen residue from the flower collect on the slide. Then, a cover slip was placed over the slide and the slide was mounted in the foldscope. For reference, in the photo below, the anthers are the tubes in the center of the flower (i.e., the part of the flower that is not the white petals).

After referencing an online site with types of white flowers, https://www.ftd.com/blog/design/white-flowers, the species of the flower shown above was determined to be Rosa ‘Iceberg’ (other photo evidence strongly supported this conclusion) under the family of Floribunda rose.

Still, I have questions about my image. 1) I am curious as to what makes some of the pollen slightly golden colored, whether it is the natural color of pollen or whether there is nectar from the flower that is mixed with the pollen. I could learn more about this by trying to isolate flakes of pollen that are not golden and flakes of pollen that are golden, and test for the presence of nectar in a lab setting. If both batches lack nectar, then this would indicate a natural discrepancy in color. If the non-gold batch lacks nectar and the gold batch has nectar, then it might indicate that nectar influences color. There are other possible outcomes too, that would suggest different conclusions about the color of pollen vs. presence of nectar.

2) I am also curious about the differences in shapes of the pollen. It would be interesting to map out the distribution of area, perimeter, area/perimeter ratios, etc. for the 2D cross sections of the pollen particles and see if there is some unifying quantitive trait that links them (and move onto 3D analysis as well). This would help me determine why the pollen particles have the shapes they do, which could be random OR determined by a mathematical property of the pollen particles.

#caltechbi1