Effects of nursery shading on plant growth, chlorophyll content and PSII in 'Lane Late' navel orange seedlings

Citrus is grown in tropical, semitropical and subtropical climate conditions. In these regions high temperature lead to reductions of the plant growth and photosynthesis. In the citrus nursery, seedlings are frequently shaded to avoid heat damage. More recently, photo-selective shade materials designed specifically for manipulating plant development and growth has decreased solar radiation and temperature. In this work, we examined the effect of different colours and shade intensities (50% aluminet, 20% Red Leno, 13% Clear combined and 75% black shade net) on one-year-old 'Lane Late' seedling growth. Leaf number, plant scion diameter, plant rootstock diameter, SPAD and PSII parameters were investigated. At the end of the experiment, leaf number was found to be higher in 75 and 50% shade net treatments. In control plants leaf number was the least among the treatments. Scion and rootstock diameter were induced in 75 and 50% shade net treatments and the other treatments were found to be similar. PSII and chlorophyll content was found to be highest in 75% shade treatment. The lowest chlorophyll content was obtained from control plants.