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

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 10 degrees C for 3 weeks in the dark or under red LED illumination at a photosynthetic photon flux density of 0.8 mu mol m(-2) s(-1) for 5, 20, 60, 240, or 1,440 mm (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 mm d(-1) was most effective at suppressing shoot elongation and reducing the loss of photosynthetic ability in cabbage seedlings during low-temperature storage.