THE EFFECTS OF LIGHT REGIME AND SUBSTRATE ON FLOWER PRODUCTIVITY AND LEAF MINERAL COMPOSITION IN TWO GERBERA CULTIVARS

Abstract

This research evaluates the influence of light regime and substrate composition on the flower productivity and leaf macronutrient content of two gerbera cultivars (‘Ruby Red’ and ‘Vino’) grown in a greenhouse. A special emphasis was given to macro-element ratios in gerbera leaf. The results confirm positive influence of supplemental lighting on flower yield in both gerbera cultivars. Also, mixed substrate (coco fiber + rice husks) resulted with higher flower yield. Cultivar ‘Vino’ showed better productivity and significantly lower concentration of nitrogen (N), potassium (K), and magnesium (Mg) as compared to ‘Ruby Red’. The total flower productivity per plant correlated with some of the tested macronutrients in gerbera leaf (N, K, Mg) only in natural light conditions. Among all calculated leaf nutrient ratios, only P/Mg was significantly and positively correlated to flower yield, based on data from both light variants.

Keywords:

• gerbera
• Gerbera jamesonii L.
• foliar analyses
• macronutrients
• light regime
• substrate composition
• flower yield

ACKNOWLEDGMENTS

This work was an integral part of the PhD thesis of Jadranka Mustapić-Karlić and research project no.: 079-0790494-0559 (“Physiological mechanisms of plant tolerance to abiotic stress”) supported by The Ministry of Science, Education and Sports, Croatia. The authors are thankful to Sara Teklić Ward and Stephen Ward for language help.