Dicot storage root, SEM

Dicot storage root, coloured scanning electron micrograph (SEM). A fracture through a dicot root showing starch storage and vascular bundles. The starch grains are within the cellulose cell wall compartments. The stored starch grains are called amyloplasts. Starch is the predominant form of carbohydrate found in a variety of root crops. Starch is synthesized from sucrose, a sugar formed in the leaves during photosynthesis & transported to the root via the phloem. All plant seeds and tubers contain starch that is present as amylose and amylopectin. Starch is an important food resource for humans and is cultivated as a crop. A vascular bundle is a part of the transport system in vascular plants. The transport itself happens in vascular tissue, which exists in two forms: xylem ( tracheids, larger vessels) and phloem (sieve tubes, smaller tubes ). Magnification: x25 at 10 centimetres wide., by STEVE GSCHMEISSNER/SCIENCE PHOTO LIBRARY