Light intensity effects on dynamic growth of kermes oak (Quercus coccifera L.)

Abstract

Kermes oak (Quercus coccifera L.) is a sclerophyllous evergreen shrub of the Mediterranean region. In Greece, it grows either atone or in a mixture with other sclerophyllous species in shrublands or as an understory in the Pinus brutia forests. The effect of light intensity on growth and productivity of Kermes oak plant at two phenological stages were investigated under two different light regimes-, as an understory species in a P. brutia forest and in adjacent open shrublands. Leaf area (LA) , twig length (L) , leaf weight (W) , total dry matter production and total non-structural carbohydrate content (TNC) were measured both at the flash-growth stage and at the end of the growing season, both in shaded and sun plants. The specific leaf weight (SEW) , relative growth rate (RGR) and the unit leaf ratio (ULR) were also estimated. Shaded plants had higher growth, LA (8,5% and 27%) and L (44% and 29%) respectively at the flash-growth stage and at the end of the growing season, but lower dry matter production as compared with the open-grown plants. The SEW and RGR had the same growth rate in the sun-and shade-grown plants, while the ULR was found to have lower values under low light intensities. This is an indication that the lower dry matter production in the shaded plants as compared to the sun plants was probably due to the higher respiration loss of the former than of the latter plants. This is supported by the lower content in TNC found in shaded plants as compared to the sun plants.