The effect of additional blue light doses in combination with an artificial solar spectrum on growth and morphology of Solanum Lycopersicum.

MSc-thesis abstract (submitted 28 May 2015):
Through its impact on photosynthesis and morphogenesis, light is the environmental factor that most affects plant architecture, which has great impact on light interception. Especially, plant sense and respond to the fraction, or the absolute amount of blue light.

Blue light can manipulate leaf and plant properties under low irradiance such they would normally be associated with high irradiances. In this study tomato plants were used to assess the effect of elevated fraction of blue light on young tomato plants growth and morphology under artificial solar background and low fluence rate.

The results showed that plants grown under higher doses of blue have developed compact morphology with shorter hypocotyls, stems, internodes and petioles, whereas there was not any difference regarding the leaf expansion and structure. Concerning the dry matter gain, there was not any differentiation due to the manipulation of the blue light. But differences were revealed on dry mass partitioning on the different plant parts, where the leaf mass fraction increased in higher blue light doses while the stem mass fraction was decreasing. Finally, total light interception seems not to be influenced by the higher doses of blue light due to unchanged leaf structure.