Effect of different spectral composition led lighting on silver birch In Vitro plantlet morphology

Abstract

Roth.) clone in vitro cultures. Three different spectral compositions – red & blue (RB), red, green & blue (RGB) and red, green, blue, yellow & orange (RGBYO) LED luminaires and fluorescent light (FL) as control were used. Photon flux density of 110 μmol m-2 s-1 and 16/8h light/dark photoperiod was maintained for all luminaires. Stem and leaf morphological characteristics were affected by clone specific reaction to light treatment, while fresh and dry weight were affected only by clone. Partially opposite effect of red light amount in combination with yellow and orange light (RGBYO and FL luminaires) was observed on total plant length and main shoot elongation for two of ten birch clones. Length of third internode (four of ten clones) and leaf total and average area (three of ten clones) were stimulated by red light in combination with yellow and orange light. In general, our study shows that silver birch in vitro cultures exhibit clone specific, light-dependent morphological plasticity. We conclude that fluorescent lamps can be replaced with RGBYO, due to optimal spectral composition emitted by this luminaire and potential to adjust proportion of red light, thus providing individual approach for propagation of high-quality genotypes.