STUDIES ON THE FORMATION AND SPROUTING OF AERIAL TUBERS IN BEGONIA EVANSIANA ANDR. VIII. DUAL EFFECT ON TUBERIZATION OF NEAR INFRARED LIGHT GIVEN IN DARK PERIODS

This preliminary report describes how the formation of aerialtubers of Begonia evansiana in response to short-days is inhibitedby near infrared irradiations given before and during dark periods.The time of application of red light during the dark period,which caused the maximum inhibition, was found to have no relationto the day. length while that of near infrared light causingthe same effect shifted from an early to a later part of thedark period as daylength was shortened. It was also observedthat the effect of near infrared light given before the darkperiod was inhibitive when the photoperiod was short, and somewhatpromotive when the latter was long. (Received October 31, 1962; )