PROBLEM TO BE SOLVED: To obtain a pressure-sensitive adhesive sheet for fixing mosses capable of carrying out treatment with abscisic acid of the mosses and enhancing the drying preservation properties, and to provide a method for treating the mosses with the abscisic acid in the pressure-sensitive adhesive sheet comprising the mosses fixed thereto in which the mosses are bonded to a pressure-sensitive adhesive tape or sheet while maintaining the community. SOLUTION: This pressure-sensitive adhesive sheet comprising the mosses fixed thereto and having the enhance drying preservation properties can be prepared by fixing base parts 5 of gametophytes of the mosses treated with a solution of the abscisic acid to one surface of the pressure-sensitive adhesive tape or sheet 2 with an adhesive.
