How many types of cells constitute phloem tissue?

Phloem tissue is composed of four main types of cells, each serving distinct functions. Sieve tube elements are the primary conducting cells that transport organic nutrients throughout the plant. Companion cells are closely associated with sieve tube elements, providing metabolic support and helping regulate transport. Phloem parenchyma cells store nutrients and assist in lateral transport of materials. Phloem fibers provide mechanical strength and support to the phloem tissue. Together, these cell types work in coordination to ensure efficient translocation of photosynthetic products, amino acids, hormones, and other organic compounds from source tissues (like leaves) to sink tissues (such as roots, fruits, and growing regions).