Eustele refers to a type of plant vascular tissue organization found in certain groups of plants, particularly within the evolutionarily advanced angiosperms. It is a pattern in which the xylem and phloem, the two main types of tissues responsible for transport within plants, are arranged in a distinct cylinder or solid core at the center of the plant stem or root.
The term "eustele" is derived from the Greek words "eu," meaning true or well-organized, and "stēlē," meaning column or rod. This perfectly encapsulates the essential feature of eustele, which is the presence of a well-defined central region containing vascular tissues.
In plants with eustele organization, the vascular tissue arrangement is highly efficient for conducting water, minerals, and nutrients throughout the plant. The xylem, responsible for water and mineral transport, is located towards the center, while the phloem, which transports organic compounds such as sugars, is present in a layer just outside the xylem.
Eustele is commonly found in various flowering plants, including most monocots, such as grasses, lilies, and orchids, as well as some dicots, like roses and sunflowers. It is a characteristic feature of evolved plants and is considered more complex than other types of vascular tissue arrangements, such as siphonosteles or protosteles, which are observed in more primitive plant groups. The organization of vascular tissues in eustele plays a crucial role in the growth, development, and survival of plants.
