Physiological dynamic response of four potted plants under the stress of formaldehyde Indoor potted plants of Marantaceae and Pteridophy-tes for purification of formaldehyde polluted air Studies on the Characteristics of Response to Photoperiod in Calceolaria × herbeohybrida‘Dainty’ Studies on the Characteristics of Response to Photoperiod in Calceolaria × herbeohybrida‘Dainty’