|Authors: ||T. Eguchi, R. Hernández, C. Kubota|
|Keywords: ||edema, LED, light quality, oedema, Solanum lycopersicum, transplants|
Effects of end-of-day far-red (EOD-FR, 700-800 nm) light and high blue photon flux ratio during the photoperiod on intumescence injury were examined for 'Beaufort' and 'Maxifort' tomato rootstock seedlings (Solanum lycopersicum × Solanum habrochaites) grown with 13 mol m-2 d-1 daily light integral (199 µmol m-2 s-1 photosynthetic photon flux, 18 h photoperiod). The EOD-FR light treatment (1.1 mmol m-2 d-1 provided by 6.0 µmol m-2 s-1 FR photon flux for 3 min at EOD) significantly reduced intumescence injury.
For example, by the EOD-FR light treatment, the incidences of leaf abscission were reduced from 88 to 8% for 'Beaufort' and from 79 to 25% for 'Maxifort'. However, EOD-FR light caused undesirable stem extension (41% greater than that without EOD-FR light). By combining relatively high B (blue, 400-500 nm) to R (red, 600-700 nm) photon flux ratio (50%B-50%R) during the photoperiod with EOD-FR light, intumescence injury was further decreased without causing undesirable stem extension.
For example, the incidences of leaf abscission were reduced from 88 to 0% for 'Beaufort' and from 79 to 0% for 'Maxifort', compared to those under 10%B-90%R without EOD-FR light.
Also, the percentages of leaves that exhibited intumescences were reduced from 68 to 30% for 'Beaufort' and from 55 to 19% for 'Maxifort'. Our study demonstrated that blue-rich light quality combined with a small dose of EOD-FR lighting could be applied to mitigate the problematic intumescence injury of tomato seedlings grown under LEDs.
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