plantsap

Plantsap is a term used to describe the viscous fluids that circulate within the vascular system of plants. In botany, sap commonly refers to two distinct fluids: xylem sap, which consists mainly of water and dissolved minerals and is transported from roots to shoots by transpiration-driven tension; and phloem sap, a richer mixture of water, sugars (primarily sucrose), amino acids, hormones, and other organic compounds moved from photosynthetic tissues to non-photosynthetic tissues and storage organs.

Composition and flow vary between the two types. Xylem sap is relatively dilute and follows a passive, upward flow driven by evaporation at the leaves. Phloem sap is actively loaded in source tissues and unloaded at sink tissues, often under pressure, enabling the distribution of photosynthates and signaling molecules throughout the plant. The relative abundance of sugars, minerals, and other compounds in sap can change with species, developmental stage, season, and environmental conditions such as drought or nutrient availability.

Functions and significance are broad. Sap provides hydration and nutrient transport, contributes to turgor pressure, and carries hormonal and defense signals that coordinate growth and stress responses. It also underpins interactions with other organisms; many sap-sucking insects feed specifically on phloem sap, influencing plant ecology and pest management. In agricultural and research contexts, sap analysis can inform nutrient management and plant health assessments. A well-known exception is maple sap, a xylem-derived fluid harvested seasonally for syrup production.