Impact of a combination of light spectra and intensities on grafted cucumber seedlings growth during healing and acclimatization

M. Mohammadian, S. Aliniaeifard, F. Bekhradi, M. Lotfi
Since newly-grafted seedlings have no vascular connections during the healing period, they are extremely susceptible to desiccation. Therefore, keeping the newly-grafted seedlings under favorable environmental conditions is of vital importance for successful production. Here the effects of combining light spectra and intensities on the performance of grafted cucumber scion on squash seedlings were investigated. Newly-grafted seedlings were placed under different light including red (R), blue (B), green (G), white (W), red:far red (R:FR), red:blue (R:B in ratios of 50:50 and 70:30) at four intensities (25, 50, 100, and 200 µmol m‑2 s‑1 photosynthetic photon flux density). Our results show that light intensity of 200 µmol m‑2 s‑1 was detrimental for seedling survival and stem fresh weight. The highest root fresh weight was obtained under 100 µmol m‑2 s‑1 of R:B (50:50), whereas the lowest values were recorded under 25 µmol m‑2 s‑1 PPFD in all light spectra. The highest root fresh weight was achieved under the highest light intensity of R and R:FR light (200 µmol m‑2 s‑1). The longest roots were recorded under 200 µmol m‑2 s‑1 of R light, while the shortest roots were detected under 200 µmol m‑2 s‑1 of G and 25 µmol m‑2 s‑1 of R:FR light. In all light spectra, the thinnest stem in the rootstock part was obtained under 200 µmol m‑2 s‑1 of G light, whereas the thickest rootstock stems were detected in 25 and 100 µmol m‑2 s‑1 of R:B (50:50), 25 and 50 µmol m‑2 s‑1 of R:FR and 50 µmol m‑2 s‑1 of B light. R:FR strongly promoted stems growth while the other light regimes did not induce significant differences. The highest leaf area was recorded using R, B and R:B light at moderate intensity. Considering that short seedlings exhibiting enough leaf areas and strongest root systme are desirable traits for the grafted seedling production, B light represents a good compromise. In an effort to save energy, both 50 and 100 µmol m‑2 s‑1can be recommended for production of grafted cucumber seedlings. Further work is needed to evaluate the possible interactions between each factor.
Mohammadian, M., Aliniaeifard, S., Bekhradi, F. and Lotfi, M. (2023). Impact of a combination of light spectra and intensities on grafted cucumber seedlings growth during healing and acclimatization. Acta Hortic. 1365, 91-96
DOI: 10.17660/ActaHortic.2023.1365.11
https://doi.org/10.17660/ActaHortic.2023.1365.11
cucumber, grafting, light intensity, light spectrum, squash
English

Acta Horticulturae