Effect of red and blue light-emitting diodes on germination, morphological and anatomical features of Brassica napus

Effect of red and blue light on seed germination, anatomical and ultrastructural features of chloroplasts were studied in oilseed rape (Brassica napus ‘Modena’). Oilseed rape seeds were germinated in 2, 4 and 8 h light under various light emitting-diodes (LED) treatments: white light (control), red light (638 nm) and blue light (450 nm) in the laboratory. In greenhouse experiment, potted plants were grown under 4, 8 and 12 days of blue and red lights and white light at the background. The photoperiod of 16 h and 28/18 °C day/night temperature and 30 % relative humidity were maintained in the greenhouse. Seed germination percentage under red light increased significantly when compared with the control; however, blue light decreased significantly germination percentage of oilseed rape seeds. Red and blue lights had negative effect on shoot and seminal root growth of oilseed rape in all the treatments. In greenhouse experiment, shoot length, plant biomass, stem diameter, were significantly increased by blue light treatment. It seems blue light treatment induces higher photosynthesis in leaves and produced higher biomass of the whole plant in this treatment than the control or red light treatment. 174 P. Farrokh Tehrani et al.