EFFECT OF THE GROWTH SUBSTANCES ON PLANT GROWTH AND SHOOT APEX DIFFERENTIATION IN GLADIOLUS (GLADIOLUS HORTORUM CV. ACCA LAURENTIA)

Gladiolus corms were soaked in water solutions of IAA, NAA, IBA, GA₃ and kinetin in concentrations of 100, 500, 1000 and 2000 ppm for 24 hours before planting in a greenhouse on 10 January 1978. All hormones except GA₃ which stimulated corm sprouting and the initial stages of shoot growth, exerted inhibitory effects on the early phases of plant growth and in the case of NAA in concentrations of 1000 and 2000 ppm dying of plants was observed.
However, this stimulatory effects of gibberellin disappeared so that a decrease in leaf length was observed in GA₃ treated plants as compared to the control.
Kinetin, IBA and NAA (the latter in the lowest concentration) eventually increased leaf length.
IBA in concentration of 100 ppm nearly doubled the cormel number.

Anatomical observations of shoot apex sections made 22 and 54 days after planting revealed the inhibition of differentation of flower primordia by all growth regulators tested with the exception of GA₃ and IAA in two lower concentrations which promoted formation of inflorescences.
None of the substances used counteracted blasting of inflorescences occurring during the later stages of plant development due to unfavorable light conditions.

Symposium on Growth Regulators in Floriculture

J. Tonecki

https://doi.org/10.17660/ActaHortic.1979.91.23