Desiccants are hygroscopic substances such as activated alumina, calcium chloride, silica gel, zinc chloride, etc. They absorb water vapor and maintain a dry atmosphere in the container meant for food packaging, chemical reagents, etc. Desiccants induce shedding of leaves by accelerated drying of various parts of the plant. Desiccants and defoliants facilitate harvesting. A tightly-closed vessel, usually of glass, containing a desiccant is used in the laboratory for drying test materials, and is known as a desiccator. Some types of desiccators maintain partial vacuum.
