Daily red LED illumination improves the quality of cabbage plug seedlings during low-temperature storage

Summary

Seedling storage can help to match supply with demand. To develop a method to preserve the quality of stored cabbage (Brassica oleracea L.) plug seedlings, we investigated the effects of the duration of daily red light-emitting diode (LED) illumination during storage on shoot growth, carbohydrate concentrations, and photosynthetic characteristics. Seedlings were stored at 10ºC for 3 weeks in the dark or under red LED illumination at a photosynthetic photon flux density of 0.8 µmol m^–2 s^–1 for 5, 20, 60, 240, or 1,440 min (continuous light) d^–1. Shoots elongated and remained succulent during storage when the duration of illumination was < 60 min d^–1. LED illumination did not affect shoot dry weight, or the concentrations of starch and soluble sugars. Regardless of its duration, LED illumination maintained high concentrations of chlorophyll and ribulose-1,5-bisphosphate carboxylase/oxygenase in the leaves. After removal from storage, seedlings stored in the dark or under continuous illumination showed lower recovery of their net rates of CO₂ fixation than all other seedlings. We conclude that red LED illumination for 60 min d^–1 was most effective at suppressing shoot elongation and reducing the loss of photosynthetic ability in cabbage seedlings during low-temperature storage.