phloemiin

Phloemiin is a term used in theoretical discussions and some educational simulations to denote a hypothetical small molecule that could influence phloem transport in vascular plants. The name combines the word phloem with a common chemical suffix to suggest a substance acting within the phloem network.

In these contexts, phloemiin is described as a polar organic compound envisioned to move through sieve tubes and plasmodesmata. Proposed modes of action include altering the osmotic balance within sieve elements, modulating the loading or unloading of photoassimilates such as sucrose, or affecting the conductivity of sieve plates and related hydrodynamic properties of the transport pathway. The concept serves to illustrate how changes at the molecular level could impact whole-plant carbohydrate distribution.

Status and sources: there is no peer‑reviewed empirical evidence for the existence of phloemiin. It has not been isolated, synthesized, or detected in plant tissues, and it does not appear in major chemical databases or metabolite catalogs. As such, phloemiin is treated as a conceptual placeholder rather than an established chemical entity.

Use and significance: in education and modeling, phloemiin is used to demonstrate principles of phloem transport, assimilate partitioning, and the potential impact of molecular regulators on source–sink dynamics. Related concepts include phloem transport, sieve elements, plasmodesmata, and assimilate partitioning.