HORMONAL REGULATION OF TUBERIZATION IN DAHLIA

SADH and ethephon promoted the tuberization in whole dahlia plants but inhibited it in budless cuttings.
ABA enhanced tuberization and GA inhibited it both in whole plants and in budless cuttings.
GA enhanced thickening at the petiole base of budless cuttings.
No anatomical difference could be observed between the GA-induced thickening at the petiole base and the natural or ABA-induced thickening of the roots.
Short day conditions which promote tuberization increased the endogenous level of ABA. Evolution of endogenous ethylene reached a peak between the second and the third week after the start of short days, one week before the onset of tuberization, and then decreased to the low level found in plants growing under long days.
It is suggested that GA and ABA directly control tuberization by determining the site of the sink for assimilates.
Ethylene may have a different effect at different stages of development, promoting the initiation of tuberization and inhibiting the later stages of tuber filling.

II International Symposium on Flower Bulbs

A.H. Halevy, I. Biran

https://doi.org/10.17660/ActaHortic.1975.47.45