Do plants actually take up salt while the water diffuses in?
Ions get into the roots via several mechanisms. Ions that are at lower concentrations outside the plant that inside are taken up by a processes called active transport which requires energy and is mediated by a protein. Ions that exist at higher concentrations outside the plant than inside can diffuse in, but again, a protein is probably involved. These proteins are called transporters, pores or channels depending on their exact nature and how they operate. Both roots and shoots of plants grown in saline environments will have higher salts levels.
