Abstract: A water-retaining support for plants comprising a hydrogel-forming polymer (A) having a calcium ion absorption of 0-100 mg per 1 g of the dry weight thereof, having a chlorine ion content of 0.07-7 mmol per 1 g of the dry weight thereof and having a water absorption magnification in ion-exchanger water at 25° C. of 1.0×101 to 1.0×102; or a plant body-growing water-retaining material comprising a molded product of a mixture of such a polymer (A) and a plant body-growing support (B). The water-retaining support for plants and the plant body-growing water-retaining material are those which have an excellent water-retaining property and they substantially do not cause inhibition of root generation or inhibition of root elongation.

Abstract: An ion complex which comprises a water-insoluble polyion (P) and a water-soluble polyion (A); and is insoluble in water and soluble in an aqueous organic solvent. Such an ion complex becomes a coating material which can preferably be used for coating of various ionic substances (e.g., substance having biological activity such as an anticoagulant property or an antibacterial property).