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How do xylem and phloem transport materials through a plant?

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fern life cycle — plant development The life cycle of the fern. (1) Clusters (sori) of sporangia (spore cases) grow on the undersurface of mature fern leaves. (2) Released from its spore case, the haploid spore is carried to the ground, where it germinates into a tiny, usually heart-shaped, gametophyte (gamete-producing structure), anchored to the ground by rhizoids (rootlike projections). (3) Under moist conditions, mature sperm are released from the antheridia and swim to the egg-producing archegonia that have formed on the gametophyte's lower surface. (4) When fertilization occurs, a zygote forms and develops into an embryo within the archegonium. (5) The embryo eventually grows larger than the gametophyte and becomes a sporophyte.

In vascular plants, xylem and phloem serve as specialized tissues for long-distance transport, functioning similarly to a circulatory system.1

Xylem Transport

Xylem conveys water and dissolved minerals upward from the roots to the rest of the plant. This process is primarily driven by the cohesion theory, where water is pulled through the plant by transpiration (the evaporation of water from leaves). As water molecules evaporate, they pull on the continuous column of water held together by cohesion and adhesion within the xylem vessels. Under specific conditions, such as in early spring, root pressure can also push water upward.213

Phloem Transport

Phloem transports the products of photosynthesis—primarily sugars—from leaves (sources) to growing tissues and storage organs (sinks), such as roots, fruits, and flowers. Unlike the unidirectional flow of xylem, phloem transport is variable and under metabolic control. The most widely accepted model is the pressure-flow hypothesis, which suggests that a pressure gradient is established between source and sink regions, allowing the solution to flow through sieve tubes.41