Manipulation of photoperiod and light intensity in low-temperature storage of eggplant plug seedlings

Eggplant (Solanum melongena L.) plug seedlings, which were grown in a transplant production chamber for 3 weeks under environmental conditions of 28/20°C photo-/dark period temperature, 330 μmol m^-2 s^-1 photosynthetic photon flux (PPF), and 16 h photoperiod per day, were stored for 4 weeks under different combinations of PPF and photoperiod. Continuous illumination (24 h photoperiod) at a PPF close to the light compensation point (5 μmol m^-2 s^-1) maintained dry weight and quality (visual quality and regrowth ability) of the seedlings during storage. Under all the other combinations of PPF (10, 24, and 40 μmol m^-2 s^-1) and photoperiod (12, 5, and 3 h per day, respectively) providing the equal daily integrated PPF (430 μmol m^-2) to that under the conditions of 5 μmol m^-2 s^-1 PPF and 24 h photoperiod, the dry weight and quality of seedlings remained unchanged during storage as was in the treatment with 5 mmol m^-2 s^-1 PPF and 24 h photoperiod. Storage in darkness resulted in dry weight loss during storage, and the quality deteriorated due to leaf yellowing. PPF, photoperiod, and daily integrated PPF were shown to be important light environment factors in the preservation of transplant quality and suppression of growth of the seedlings during storage.