Articles
TEMPERATURE EFFECT ON SOME FOLIAGE PLANTS GROWN UNDER POOR LIGHT CONDITIONS
Because of this low light intensity and the very short daylength, plantgrowth conditions are poor.
The daily radiation in December and January at Aas is estimated to less than 25 gm.cal.cm-2. It is assumed that when no artificial light is used, it is necessary to lower the temperature in the greenhouses in that season, even when foliage plants are concerned.
Temperature experiments carried out the last three winters in the phytotron at Aas, however, show that some foliage plants seem to grow well under poor light conditions if give optimal temperatures.
Young plants, well rooted after potting, were left in rooms with temperatures 12, 15, 18, 21 and 24°C. Some plants were left at these temperatures constantly days and nights, while others received different day- and nighttemperatures.
The experiments were started in November and finished in February each year.
The development of new leaves, plant height and fresh weight were recorded.
Some of the plants died or were damaged at low temperature.
Codiaeum and Dieffenbachia for instance could not tolerate 12°C.
Rhoicissus rhomboidea, Philodendron scandens got injured leaves at 12°C, and the same happened to Raphidophora aurea at lower temperatures than 18°C.
Table 1 shows temperatures which on basis of these experiments, seem to be optimal, and those temperatures which can be tolerated without any damage, are given.