Innovative Photoselective and Photoluminescent Plastic Films for Protected Cultivation

The aim of this research was to investigate the radiometric properties of innovative covering films for protected cultivation capable of modifying the spectral distribution of the transmitted radiation and thus the vegetative activity. Two photoselective films, three photoluminescent films and one low-density polyethylene film were used as greenhouse coverings for potted wheat (Triticum durum) plants. The transmissivity of the different films under natural radiation was measured to compute R/FR and B/FR ratios. The photoselective films were characterised by a reduction of the R/FR ratio in comparison to the natural solar radiation. Gas exchange, measured as stomatal conductance, and plant growth were monitored from emergence until the phenological stage of booting. When compared to the photoluminescent films, the photoselective films induced an increase in stem height and dry matter, and a decrease in stomatal conductance, lateral tillers and leaf area. Under the photoselective films and under the low-density polyethylene control film the emission of lateral tillers was slightly lower than in open field.