STUDIES ON THE FORMATION AND SPROUTING OF AERIAL TUBERS IN BEGONIA EVANSIANA ANDR. IX. EFFECTS OF TEMPERATURE ON TUBER INITIATION

Abstract

The effects of temperature on the aerial tuber initiation of Begonia evansiana Andr. in response to short-day condition were investigated. Tuberization was inhibited by relatively low and high temperatures during the dark periods. The optimal nycto-temperature was 23° and hardly changed by not only photo-temperature but also daylength. There were two temperature-sensitive phases in the dark period; one came at its beginning, and the other later one came at various times depending on the length of the light period. Low temperatures were effective at both of these sensitive phases, but high temperatures had an influence only at the later one. Photo-temperatures exerted little influence on tuberization under the sub-optimal daylength, but the lower temperatures were promotive under longer daylengths.