Light micrograph (LM) of protoxylem in transverse section. Xylem is one of two types of transport tissue in vascular plants, the other being phloem. Its basic function is to transport water, but it also transports some nutrients. Protoxylem is the first xylem to develop in a young plant. It is distinguished in appearance by narrower vessels formed of smaller cells. Magnification: 120X at 4x6"