COVER FILMS AND LIGHT QUALITY RESPONSES IN SAINTPAULIA IONANTHA

The use of cover films with different light transmission spectrum have been introduced in commercial greenhouse of ornamental plants without a previous evaluation.
Forty Saintpaulia ionantha plants were grown under each three different cover films: (1) CONTROL [red:far red ratio = 1.1; blue:red ratio = 0.33; blue:far red ratio = 0.37], (2) RED [red:far red ratio =0.9; blue:red ratio = 0.0035; blue:far red ratio = 0.0033] and (3) BLUE [red:far red ratio = 0.02; blue:red ratio = 7.2; blue:far red ratio = 0.17] at similar photosynthetic photon fluence rate.
Plants grown under RED and BLUE films showed a decrease in the main growth parameters evaluated.
Net photosynthetic rate (mg CO₂ m^-2 s^-1) were signifficant lower under RED and BLUE cover plastic.
These results determined a lower photoassimilated accumulation (expressed as plant dry weight) at RED and BLUE treatments.
The decrease in leaf shape would be related to a lower photosynthetic assimilates availability under cover plastics which changes solar light spectrum.
The response increased when new leaves were expanded.
An effect of light quality on biochemical reactions of photosynthetic system would be proposed.

XXV International Horticultural Congress, Part 5: Culture Techniques with Special Emphasis on Environmental Implications Chemical, Physical and Biological Means of Regulating Crop Growth in Ornamentals and Other Crops

C. Boschi, A. Di Benedetto, P. Papayani, C. Cremona, D. Benedicto

Photosynthesis, photomorphogenesis, pot plant

https://doi.org/10.17660/ActaHortic.2000.515.16