Response of potted plants of tropical origin to changes in the night temperature regime

Abstract

Growth of 1-year-old plants of Ficus benjamina cultivars ‘Golden Princess’ and ‘Starlight’, but not of young ‘Starlight’ plants, was inhibited when they were grown at a night temperature of 12°C in comparison with 18°C. Exposure of the plants to alternating night temperatures promoted growth of the young ‘Starlight’ plants, but did not affect the older plants of either cultivar of Ficus benjamina in comparison with plants grown at 18°C. Growth and branching (number of lateral shoots) of croton ‘Petra’ were promoted by exposure to an alternating night temperature regime relative to a constant temperature of 18°C. The growth of ‘Norma’ was promoted under such conditions only when plants were decapitated. Alternating temperature caused an increase in the number of lateral shoots of Peperomia and Pilea, although the variegated Peperomia was not affected. The growth of Areca palms was not affected by alternating night temperatures in comparison with a higher constant temperature. Stem length, fresh weight and development of lateral shoots, but not new leaves of Diffenbachia, were suppressed by exposure to an alternating temperature regime in comparison to a constant higher night temperature.