Lennutransport

Lennutransport is a term used in physiology and ecology to describe the movement of nutrients across biological barriers or through space over extended distances. The concept encompasses processes that move essential elements such as sugars, amino acids, minerals, and vitamins from sites of uptake or production to tissues or ecosystems where they are used or stored.

In organisms, long-distance nutrient transport primarily occurs through circulatory systems. Nutrients absorbed in the gut or produced in tissues enter the bloodstream or hemolymph and are distributed to organs through flow driven by the heart or heart-like pumps; cells access nutrients via transport proteins and vesicular trafficking. In plants, long-distance transport occurs in the xylem and phloem; the xylem conveys water and mineral nutrients from roots to shoots, driven by transpiration, while phloem distributes photosynthates and other solutes from source to sink by pressure-flow mechanisms.

Molecular mechanisms involve channels, carriers, and pumps that move nutrients across membranes, with regulation by hormones and signaling pathways that adjust uptake, loading, unloading, and storage according to need and environmental conditions. Energy-dependent steps include active transport and vesicular trafficking, while passive steps include diffusion and bulk flow driven by pressure gradients.

Lennutransport is central to growth, metabolism, and homeostasis. Impairment can contribute to diseases such as diabetes or iron-deficiency anemia in animals and nutrient deficiency or toxicity in crops. Understanding lennutransport informs agriculture, medicine, and ecological studies of nutrient cycling and ecosystem productivity.

Because lennutransport is not a standardized term with universal definition, its meaning varies across sources. Some use it specifically for long-distance transport within organisms; others apply it more broadly to inter-organism or environmental nutrient fluxes within ecosystems.