We have developed a technique to stimulate flower shoot emergence of Phalaenopsis plants, which requires temperature at about 20°C for flower shoot emergence in the summer. In a nonair-conditioned greenhouse, mature Phalaenopsis plants were placed between guide rails on which an insulated cabinet moved back and forth. The cabinet completely covered the plants from 10:00 to 16:00, when air temperature and irradiance in the greenhouse were high, and from 19:00 to 5:00 (night). When it was colsed, air temperature inside the cabinet was keps at 20°C. During other periods of the day, the plants were exposed to ambient greenhouse conditions.
The treatment started July 12, 1992 and continued for 12 weeks. The Phalaenopsis plants continued their growth and showed leaf area increases similar to plants in the greenhouse without the treatment. Flower shoot emergence was stimulated by the treatment, while no emergence was observed without the treatment. The number of florets per plant and number of days to anthesis were comparable to those observed when other methods are employed for flower shoot initiation, such as temporary relocation of plants to a coolar place and air-conditioning of the entire greenhouse.
This technique can be applied to greenhouse cooling. When the cooling area is covered by aluminum coated film, the heat load of air-conditioning due to radiand energy will be reduced during the daytime.
