Results of the first photobiological studies of optimisation of LED phyto irradiators spectrum and irradiance level, when growing salad­greengrocers plants in greenhouses and plant factories in photoculture conditions, are presented in the article. The results are given as a series of producing capacity curves for salad and basil plants when irradiating by quasi­monochromatic spectrum for three PAR ranges: blue, green and red. In the experiment, levels of photosynthetic photon irradiance (70 ? 230) µmol/s·m2 and of irradiance (13 ? 60) W/m2 were varied within a wide range. “Rough” spectra of optical radiation action estimated over producing capacity of plants with different irradiance levels are given, and questions of additivity of different spectral radiation influence in forming vegetable biomass are considered. Evaluations of efficiency of various PAR intervals for synthesis of biochemical combinations determining nutrition facts of the studied cultures are performed.

The results of the ending phase of photo biological studies of capacity of lettuce and basil grown in conditions of a phytotron with irradiation by radiation of different ratio of fractions in the red-blue and blue-green-red regions of photosynthetic active radiation (PAR) are presented. The spectral variants of PAR providing the maximum or near to maximum capacity of the specified cultures are found. The complex and multiple-valued nature of effect of main PAR spectral regions on photo energetic and photo regulatory processes in plants providing their capacity is highlighted, which makes it impossible to determine common unified requirements to optimal parameters of artificial irradiation for growing of plants. These requirements shall be defined on the basis of direct photo biological experiments with main species of agricultural plants and be the most important element of the general photo culture macro technology. The general principles of fulfilment of the specified requirements to PAR spectra of phytoemitters are reviewed, including with consideration of setting of normal vision conditions for personnel of greenhouses and other protected ground structures.

Contemporary light engineering is ready to make its contribution in the development of new, automated and (in the nearest future) fully computerised production facilities based on application of artificial irradiation for technological purposes. It is referred to cultivation of plants using the photo-culture technology in multi-layer phytoinstallations with spectral characteristics and level of irradiation taking the species and tasks of cultivation into account. The major type of plants for these installations is lettuce cultures, consumption of which in Russia significantly lags behind the recommended values, especially during winter. The article reviews major specifications of LED-based irradiation devices and lighting systems based on them, used for cultivation of lettuce in automated multi-layer phytoinstallations in photo-culture environment. An example of such phytonstallations is the automatic research installation developed in S.I. Vavilov VNISI, which has no parallel in Russia. A principal distinction of the irradiation devices used in this installation is application of multi-component LED compositions based on white and colour elements allowing us to vary spectral characteristics in the PAR region within a wide range. Generally, the installation is notable for contemporary hardware and availability of computer control.

The present study comprises comprehensive research of red, green and blue light emitting diodes (LED), which are widely used in phytoirradiators for plant growing in protected ground in the environment of a photo-culture including their spectrum measurements within the wide range of current values at room temperature. Shifts of spectral peaks of radiation of red and green LEDs after increase of operating current were discovered. On the basis of the conducted study, recommendations for selection of current operating mode of light sources used in phytoirradiators for plant growing in the environment of photo-culture were worked out, and a model of a phytoirradiator was proposed and studied in this work with red, green and blue LEDs, which have their spectrum covering all regions of photosynthetic active radiation (PAR).

No abstract