キュウリ挿し穂の低温貯蔵中における短期間の供給培養液の加温処理が貯蔵中の品質および貯蔵後の発根に及ぼす影響

Abstract

Nutrient solution supplied to cucumber (Cucumis sativus L.) cuttings during low air temperature storage was warmed for 1 day to reduce water stress of cuttings during storage and advance their rooting after storage. Cuttings were stored for 7 days in air temperature of 12-14°C with photosynthetic photon flux density of 12 μmol m-2 s-1. Nutrient solution was supplied to the cuttings through the hypocotyl cut-ends during storage. The nutrient solution temperature was maintained at 28°C for 1 day after starting of storage or before end of storage. The nutrient solution temperature was maintained at 14°C on other days. During storage, fresh weight and relative chlorophyll content of the cuttings treated in nutrient solution of 28°C for 1 day after the starting of storage was maintained higher than those that were untreated. Three days after planting the cuttings following storage, root fresh weight of the cuttings treated in nutrient solution of 28°C for 1 day after the starting storage or before the ending storage was 1.7-1.8 times as large as those that were untreated. Treatment using the warming nutrient solution increased water absorption rate and transpiration rate of cuttings ; moreover, it reduced wilting of cuttings during storage. These results indicate that application of nutrient solution of about 28°C for 1 day after the starting storage reduced the water stress of the cuttings, maintained high chlorophyll content, and advanced rooting after the end of storage in comparison with nutrient solution of about 14°C during storage. As a result of applying the treatment at various temperatures, the rooting after storage was most promoted at 29-36°C.