Effects of Plant Age and Time of Transfer to Highland during Summer on Phalaenopsis Flowering

Abstract

Phalaenopsis plants, three to six years of age were transferred from lowland (Koshigaya, Saitama Prefecture) to highland (Nasu, Tochigi Prefecture) in summer 1979 and 1980 to see if plants flower earlier.
1. Koshigaya is located close to sea level and the height of Nasu is around 500 meters from sea level and it is cool enough to induce orchid flowering.
The plants used in this experiment had reached the stage at which plants differentiate flowers by cooling.
2. Plants, when transferred to highland, formed flower-stalk two months earlier and flowered three months earlier than plants kept at lowland.
3. Although number of flower-stalks were few on three year-old plants which had not flowered before, the plants aged four or more years and had flowered before tended to produce more flower-stalks with age.
4. Plants, when transferred to highland, formed first flower-stalk at one higher node than those at lowland, regardless of their age or time of transfer.
5. The node where flower-stalk was formed decreased in number and in length as well. The spikes and number of flowers per stalk also decreases in number by transferrence, no matter when transferred or what age of plants were used.
6. Concerning the length of time from start of cooling to flowering, the younger plants flowered later.
The time of bringing down the plants from highland to lowland caused time of flowering to be delayed, when they were brought down too late.