How Mineral Ions transport in Plants

The plant vascular system carries out two essential functions, namely the delivery of resources (water, essential mineral nutrients, sugars, and amino acids) to the various plant organs, and the provision of mechanical support. In addition, the vascular system serves as an effective long-distance communication system, with the phloem and xylem serving to input information relating to abiotic and biotic conditions above and below ground, respectively. This combination of resource supply and delivery of information, including hormones, peptide hormones, proteins, and RNA, allows the vascular system to engage in the coordination of developmental and physiological processes at the whole-plant level. 

Xylem tissues may well have evolved independently from WCCs (water-conducting cells)/hydroids. Although hydroids have a number of similar features to the early tracheary elements, including functioning after death, there are many important differences. A further defining feature of the early vascular plants was that their tracheary (water-conducting) elements had pits of varying architecture that spanned the secondary wall. In contrast to the WCCs of the bryophytes, the formation of these pits is not dependent upon the dissolution of plasmodesmata (PD) and in the early tracheary element, the tracheid, the primary cell wall remains imperforate.