Lavandula latifolia Medik. grown with LED emitting diode light technology, an initial approach

Spike lavender (Lavandula latifolia Medik.) is an aromatic-medicinal plant, native to the Mediterranean region. It is cultivated for the production of essential oil and Spain being the largest producer with 150-200 t per year of these plant. Although LED technology is widely used in horticultural and fruit crops, to the best of our knowledge, there has been no attempt to use this technology to improve this lavandula species. Some authors indicate that LEDs could influence the ways of response of plants in terms of growth, as well as the production of chemical compounds. Furthermore, exposure to different LED spectra could be used to induce changes in the molecular structure of plants, increasing their ability to overcome stressful situations such as drought or salinity. In light of the above, our goal was to make a preliminary study on the effect of different LED wavelengths (blue, red and white) on the growth, polyphenolic profile and antioxidant activity of spike lavender. To this end, spike lavender plants resulting from in vitro culture were acclimated under greenhouse conditions for two months. Subsequently, ten plants were assigned randomly to three homogeneous groups and transferred to LED light chamber for 35 days. One group of plants was exposed to blue light, one to red light and the third to white light (control) with a photon flux density (PFD) of 35 μmol m^‑2 s^‑1. Growth parameters, antioxidant activity and polyphenolic profile were measured in the leaves of each group. At the end of the experiment, plants exposed to blue light showed greater growth than the red and control groups, as well as higher antioxidant activity. However, plants exposed to red light showed a significant increase in σ-coumaric acid compared with blue and control treatments.