Pollen Analysis

Pollen and Spores objectives distinguish between and explain how pollen and spore evidence can be used in crime investigation define a pollen fingerprint classify the different organisms that produce pollen and spores compare and contrast the female and male reproductive parts in plants distinguish between gymnosperms and angiosperms

Pollen Samples Are unique to each species Vary in appearance, size and color Can last unchanged for extended periods of time

Forensic palynology is a specialized field that studies pollen and spore evidence Since both pollen and spores have resistant structures, they at times can help determine such things as whether a body was moved, a crime’s location, whether it occurred in a city or in the country, or in which season it may have occurred.

Pollen/spore-Producing Plants Forensic palynologists know each pollen-producing plant provides a pollen fingerprint—a specific type of pollen grain. They also know there will be a certain number of grains found in a specific geographical area during particular times of the year. –Examples of non-seed plants (spores) would be ferns, mosses, liverworts, and horsetails. –Examples of seed plants would be gymnosperms (cycads, ginkgoes, and conifers like an evergreen) and angiosperms (flowering plants like roses).

Gymnosperms Gymnosperms are the oldest seed plants. Evergreens are conifer gymnosperms. They produce their seeds in a hard, scaly structure (cones). Pollination occurs when pollen is transferred from the male cones to the female cones. Which of the two structures shown above transfers pollen to the other?

Angiosperms The most recent plant group to evolve is known as the flowering plant. Identify its different parts in the illustration above. Plants in this group produce seeds in an enclosed fruit. These plants are very diverse and include corn, oaks, maples, and the grasses.

Spore producers Spore producers include certain protists (algae), plants, fungi, and the bacteria that produce a unique type of spore. Bacterial spores, endospores, can cause diseases such as anthrax and botulism. Spore analysis has the advantage that the spores possibly can be grown and the species identified with certainty.

Evidence

Collection of evidence During an investigation, control samples must be collected as well as evidence samples. Samples must be collected wearing gloves and with clean tools (such as brushes and cellophane tape) and placed in sterile containers, which then must be sealed and labeled with care. Sampling instruments must be cleaned after each use, or new ones must be used. Collected evidence must be secured, and the chain of custody must be maintained

Examine evidence To identify pollen and spores, specialists can use a compound light microscope, a scanning electronic microscope, reference collections that may consist of photos and illustrations or perhaps even actual dried specimens arranged systematically (herbariums). Pollen and spore evidence that has been collected, analyzed, and interpreted can be presented in court. These “fingerprints” can be used to confirm certain aspects of a crime.

Match suspect with crime scene Any residue found to be a match on clothing, shoes, or person could place suspect at the scene Flower Pine tree

All pollen is unique

You can identify the type of plant and maybe its location by its pollen

Angiosperm structure

Lily pollen