Vascular tissue

Vascular tissue transports water, minerals, and sugars through plants. Its two main types, xylem and phloem, differ in what they carry and how they transport it.

Xylem: Plant vascular tissue that conducts water and dissolved minerals, chiefly from roots toward shoots. It carries water and minerals, the main substances transported by one branch of vascular tissue.
Cohesion-tension theory: An explanation of xylem water transport in which transpiration creates tension that pulls a cohesive water column upward. It explains how water can rise through xylem without a pump.
Girdling: The removal of a ring of bark that disrupts phloem transport around a woody stem. It demonstrates how interrupting phloem flow affects tissues above the cut.
Vascular plant: A plant with specialized conducting tissues, including xylem and phloem. Vascular tissue defines this broad group of land plants.
Phloem: Plant vascular tissue that transports sugars and other organic compounds between sources and sinks. It distributes sugars, complementing xylem's transport of water and minerals.
Transpiration: The loss of water vapor from plant surfaces, especially through stomata. Evaporation from leaves generates the pull that drives xylem flow.
Grafting: A horticultural technique that joins tissues of two plants so they grow as one. A successful graft depends on reconnecting vascular tissues across the join.
Plant anatomy: The study of plant structure, including cells, tissues, and organs. Vascular tissues are a major component of plant internal structure.
Tracheid: An elongated, water-conducting xylem cell with tapered ends and thickened walls. Tracheids are water-conducting cells found throughout vascular plants.
Pressure-flow hypothesis: An explanation of phloem transport in which sugar loading and unloading create pressure differences that move sap. It accounts for long-distance sugar movement through phloem.

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