Effect on the Quality of Grafted Tomato Plug Seedlings of Blue-light PPFD Percentage during Red and Blue LEDs Low Light Irradiation Storage

Abstract

Grafted tomato (scion : Lycopersicon esculentum Mill. cv. House Momotaro ; rootstock : cv. Kagemusha) plug seedlings were stored for 35 d at 10°C under total photosynthetic photon flux density (PPFD) of 2μmol m-2s-1 using mixed light from red and blue light emitting diodes (LEDs), with different percentages of blue-light PPFD (0%: R100, 2%: R98B2, 5%: R95B5, 10%: R90B10, and 50%: R50B50) . The stored seedlings were transplanted and then cultivated for 28 d at 27°C and 290μmol m-2s-1 PPFD from white fluorescent lamps during the 12h light period and at 18°C during the 12h dark period. The effect of blue-light PPFD percentage was investigated and the best percentage was synthetically determined based on 5 and 8 items for the last days of storage and cultivation, respectively. An improving tendency was observed by increasing the percentage of blue-light PPFD in visual quality scores and leaf area on the last day of storage, aerial- and subterranean- part dry weights on the last day of cultivation. There was no applicable tendency in other items with increasing the percentage. It can be concluded that the 50% of blue-light PPFD was the best percentage among the tested ones and increasing the percentage up to 50% contributed to quality improvements for low light irradiation storage of grafted tomato plug seedlings at 10°C and 2μmol m-2s-1 PPFD from red and blue LEDs.