2008 Volume 7 Issue 2 Pages 235-240
The effect of temperature on the occurrence of yellow-leaf-spot, a physiological disorder of cut chrysanthemum, was investigated in ‘Seikou-no-makoto’ chrysanthemum. After long day treatment, plants were grown under natural day length in a temperature gradient chamber (TGC), in which air temperature followed the fluctuation of outside ambient temperature. Slight yellow-leaf-spot occurred in plants grown at intermediate temperature in TGC. This temperature regime was similar to the temperature regime before transfer to TGC. However, yellow-leaf-spot occurred remarkably higher in low or high temperature regimes. To investigate the effect of fluctuation of temperature on the occurrence of yellow-leaf-spot, plants were grown in low, intermediate and high temperature regimes in TGC, and after 10 days, plants were transferred to other temperature regimes or grown under the same temperature. The occurrence of yellow-leaf-spot was slight in low or intermediate temperature regimes 10 days after the start of treatment, but severe in high temperature regime. The occurrence of yellow-leaf-spot remarkably increased in plants transferred from high temperature regime to low temperature regime. In conclusion, the occurrence of yellow-leaf-spot in ‘Seikou-no-makoto’ was promoted by high temperature, and further increased by a drop in temperature after exposure to a high temperature.
