Studies on the Flower Initiation of Spring Wheat in Sterile Culture

I. Effects of Photoperiods and Photo-sensitive Growth Stage

Abstract

1) The spring wheat, Konosu No. 25, was cultured aseptically in test tube containing the modified White's medium under various light conditions.
2) The flowering and growth of spring wheat were depressed under the prolonged short days, and especially in darkness.
3) The photoperiods inserted in continuous darkness promoted flowering and growth. The photoperiod of 5 days was not enough for flowering, but that of 10
days was sufficient.
4) The early growth stage from the sixth to the tenth day after germination was most sensitive in photoperiodic response. The sensitivity decreased gradually with proceeding growth stages in dark culture.
5) The plants cultured in darkness for 50 days did not initiate flower primordia, but those cultured for 160 days initiated on the tillers and rarely on the main axes.