EFFECTS OF ROOT- AND AERIAL PART SUPPRESSION IN THE PLANT ON FLOWER INITIATION IN THE TULIP BULB

Bulbs of tulip, cvs. "Apeldoorn" and "Paul Richter", were used to produce 4 types of plants possessing, in addition to the mother-bulb, all- or only a part of their organs : normal plants, C ; plants whose aerial parts were suppressed and which only possessed roots, R ; plants whose rooting plate was suppressed and which only possessed aerial parts, A ; and non-planted bulbs, B, whose daughter-bulbs enlarged in the absence of root- and aerial part growth.

The absence of roots and aerial parts affects plant growth and strongly influences the capacity of the daughter-bulbs to initiate a flower.
In the absence of active roots, flower initiation occurs in very small bulbs : 3 g for "Paul Richter" and 5 g for "Apeldoorn". When plants only possessed roots, the daughter-bulbs have to be much heavier to initiate a flower : 7 to 9 g for "Paul Richter" and more than 9 g for "Apeldoorn". These results indicate that the presence of active roots in the plant negatively affects floral induction in the tulip bulb.

Root suppression, sample A, leads to an earlier plant maturity and to an earlier flower differentiation in the daughter-bulbs.

IV International Symposium on Flower Bulbs

M. Le Nard

https://doi.org/10.17660/ActaHortic.1986.177.23