Pomegranate Tree Pollen
This image shows the pollen grains in clear detail.
Pollen sample of Punica Granatum (Pomegranate tree) viewed under a Foldscope.
This tree was found on Caltech campus, Pasadena, California, just East of the South houses. The sample was taken on the 8th of May 2019 at 5:30pm.
The sample was taken by tapping a healthy flower on the tree which had large amounts of pollen, and letting the pollen fall onto a microscope slide. A cover sheet was placed on top to seal the sample. The pollen is very small and groups in approximately 0.3-2mm bright yellow clumps.
As is visible under the microscope, the pollen stays in a clump. The shown image group has diameter 0.9 mm. Each pollen is a small oval shape within this greater group.
The magnification of this image is M = 55/0.9=61. Thus, the size of the pollen grains is 0.03 x 0.01 mm (length x width). The lighting used was a bright white background.
This tree has some history, as it is the Senior Class of 2006 gift. The tree has grown fruits in previous years near Summer.
This tree seemed to be in full bloom.
The age of this tree is currently unknown, however this information could be determined by finding out more about the tree’s history. Since it is a Class of 2006 gift, it is likely that there is knowledge about the tree’s age.
I am also interested in in what is contained within the pollen – its structure. This could be determined by using a microscope with a higher magnification.
I am also interested in understanding what causes the pollen to form into groups of ~1mm in size. This could also be determined from closer investigation of the pollen.
While investigating the tree type, I learned that pomegranate pollen does not spread by itself, and pollination must occur via a symbiotic relationship with insects, in this case usually bees. In this case, what species are the insects that pollinate this tree, and when/where can they be found? This question can be answered by observation of the tree at various times of the day.
The tree’s pollen was not observed to fluoresce. This was determined by shining a UV LED lamp on the sample, which did not glow significantly. Using UV light during microscopy also did not lead to interesting results.
UV microscopy did not lead to interesting results.

• Other flowers. The pomegranate’s characteristic hard skin texture can be seen on the flower on the right. Notice the pollen lying on its petals.
• Flower that was sampled
• Full tree

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