Radiometric properties of photoselective and photoluminescent greenhouse plastic films and their effects on peach and cherry tree growth

Two photoselective and three photoluminescent greenhouse plastic films were studied for their effects on the spectral distribution of solar radiation and their influence on the growth of cherry and peach trees in the field and in laboratory tests. The two photoselective films modified the ratio of the photon fluence rate in the red to that in the far-red (R/FR), while the three photoluminescent films increased both the blue and red solar radiation by moving energy from the ultra-violet range to the blue and red wavelength range. The photoselective film that reduced the R/FR ratio, from 1.14 (open-field) to 0.93, enhanced shoot growth in peach (46.1 cm) and cherry trees (68.7 cm) compared to trees grown in the open-field (13.5 cm and 39.3 cm for peach and cherry trees, respectively). Trees grown under the red-emitting photoluminescent film showed increases in shoot length of 27.2 cm and 55.8 cm for peach and cherry trees, respectively; while plants grown under the blue-emitting photoluminescent film showed increases of 22.4 cm and 48.9 cm for peach and cherry trees, respectively. This research showed that a significant enhancement of shoot growth in peach and cherry trees can be obtained using plastic films that modify the spectral distribution of solar radiation. Further research should explore the potential for the development of film-additives that promote more compact vegetative growth.