Effects of different light quality and biofertilizers on structural and physiological traits of spinach plants

In this work, the effects of light quality and beneficial microbes (biofertilizer) supply on structural and ecophysiologicaltraits of spinach were investigated. Plants were grown under four light quality regimens: white light (WL), red-blue (RB),red-green (RG), and red (R) light, with or without the addition of biofertilizer. RG and R plants without biofertilizershowed morphological traits typical of shaded plants as wide leaf lamina and high photosynthetic pigment content. Theseplants also exhibited a higher photosynthetic capacity compared to WL and RB plants. The improved photosynthesis in RGplants was due to both morphological and physiological adjustments allowing a better utilisation of light energy, whereasin R plants it has been attributed to a reduced photorespiration rate. Biofertilizer application under WL improved plantperformance enhancing photosynthesis. The high carbon gain compensates the costs of symbiosis. Biofertilizer applicationunder R light favouring too much the microbial root colonisation, removed the benefits of symbiosis. The interaction oflight quality and biofertilization significantly affects the root-microbe relationship.