INTERACTIONS BETWEEN LIGHT, TEMPERATURE AND CO₂ IN ROOTING OF CONIFER CUTTINGS

The effect of artificial light, CO₂ and temperature on rooting was studied in ornamental cultivars of Chamaecyparis, Cupressocyparis and Juniperus species.
The effect on rooting, growth and development varied with season and the species or cultivar concerned.
Light could depress or enhance rooting percentages.
In general, it enhanced the increase in fresh weight.
CO₂ enrichment had positive effects on rooting percentages, numbers of roots and the increase in fresh weight and dry weight of the cuttings.
Interactions-between artificial light and CO₂ were found for rooting percentages, number of roots and for fresh and dry weight.

CO₂ levels in propagation units in climate rooms varied with light intensity and temperature.
In general, rooting was better at a constant temperature of 23°C than at 17°C and 29°C. Juniperus rooted better under a high light intensity (66–83 μmol.sec^-1.m^-2), but Chamaecyparis and Cupressocyparis rooted better under a low light intensity (27–37 μmol.sec^-1.m^-2).

The feasibility of predicting the effect of climate conditions on the rooting is discussed, on the basis of the results obtained in the glasshouse and in growth chambers.

III International Symposium on Artificial Lighting in Horticulture

B.P.A.M. Kunneman, J.B. Ruesink

https://doi.org/10.17660/ActaHortic.1997.418.12