Potato starch grains (Solanum tuberosum)

Light micrograph of starch grains viewed with polarised light. Starch grains are produced throughout plant tissues, most highly concentrated in structures requiring long term energy storage such as the seeds, fruits and roots. They are composed of two glucose polymers (amylose and amylopectin) and are contained within amyloplasts. Their characteristic morphology, birefringent properties and the relative position of the arms of the polarisation cross, formed when viewed under cross-polarised light, allows for family, genus and, in some cases, species level identification of the plant from which the starch grains originated. Cross-polarised light micrograph; x 10; starch grains are approximately 30 micrometers in length.