THE INFLUENCE OF TEMPERATURE AND WATER POTENTIAL ON ROOTING OF POINSETTIA CUTTINGS (EUPHORBIA PULCHERRIMA L. ‘LADY’)

The water retention curves and oxygen diffusion rate (ODR) was investigated for Jiffy-7, Grodan, and Jiffy-9.

There was found only small differences in air content at low tension (< 4 cm), but at higher tensions there was considerably more air in Grodan than in Jiffy-7 and Jiffy-9.

The oxygen diffusion rate (ODR) measured with the platinum electrode was higher in Jiffy-9 than in Jiffy-7 and Grodan at the same tension.
The diffusion coefficient was higher in Grodan than in Jiffy-9 at low tension (low air content). At high tension the opposite was the case.

The rooting of Poinsettia cuttings proved to be very difficult when the rooting media were subjected to 0 cm tension, but at higher tension the cuttings formed roots rather easily.

When the temperature of the rooting media was raised from 20 to 26–28°C the rooting of the cuttings increased significantly.

Symposium on Propagation in Arboriculture

H.R. Gislerød

https://doi.org/10.17660/ActaHortic.1975.54.17