Abstract
Grafted tomato (Lycopersicon esculentum Mill., scion: cv. Momotaro; rootstock: cv. Herupa M) plug seedlings were stored at 10°C for 28 d under different gas compositions (0.05% CO2+20% O2, L; 0.5% CO2+ 10% O2, M; 1% CO2+5% O2, H) at a photosynthetic photon flux density of 0 (dark, D) or 2 (low light irradiation, LLI, using an array of red light emitting diodes, R) μmol m-2 s-1. The percentages of the seedlings with subjective visual quality scores 5 and 4 (seedlings with scores 5 and 4 are considered stored successfully and acceptable) in MR and HR were both about 70% on the last day of storage (day 28), while the percentage in LD (control: usual low temperature storage) was 0%. The total percentage of the seedlings with scores 5 and 4 in LD, MD and MR did not fall below 90% until day 9, day 15 and day 24, respectively, indicating that acceptable storage duration of the seedlings stored under controlled atmosphere (CA) and CA combined with LLI was prolonged nearly 1.7 times and 2.7 times longer, respectively, than that under usual low temperature storage. There was no significant difference in dry weight of the seedlings in R between day 0 and day 28, while the seedling in D lost their dry weight during storage. Regardless of the gas composition, survival percentages of the seedlings after storage in R were 100%, in contrast to 20% in LD, 60% in MD and 80% in HD. These results indicate that CA combined with LLI was more effective than both CA without LLI and LLI without CA, respectively, for low temperature storage of grafted tomato plug seedlings with high visual quality and growth potential after storage.
