HEIGHT CONTROL OF A BEDDING PLANT (SALVIA SPLENDENS F. SELLOW) BY COPPER SULPHATE FILTERS

This work describes a series of experiments performed with the aim of exploiting the possibilities of using high R/FR light, obtained with copper sulphate filters, as an environmentally friendly technique for the control of plant height.

Plantlets of Salvia splendens were grown under growth chambers made with polycarbonate panels filled with water and a solution of commercial copper sulphate at 8%.

The light filtered by water panel filters decreased only the light level, while the copper sulphate filter induced lower level of light and an higher R/FR. ratio in comparison to water filter and greenhouse natural light.

The experiment consisted of four different treatments: plants under water filter panel (W), under water filter panel + 15 minute-supplementary-end-of-day red light (W+R) and under copper sulphate growth chamber (all at the same Photosynthetic Photon Flux, P.P.F.) and plants placed in greenhouse.

The copper sulphate-induced reduction of plant height was between 22–48 %, depending on the environmental light conditions, but plant height was never shorter than greenhouse control.

It appears, that, in our experimental conditions and for this plant, is not possible to suggest the use of copper sulphate filter as a valid technique for the reduction in plant height.