Chilling-tolerance of squash (Cucurbita moschata Duch. cv Shirogikuza) cotyledons was measured after 3 d of cold acclimation at 12℃. Squash seedlings grown at 12℃ (chilling-treated, CT) and 25 ℃ (non-treated, NT) were analyzed to examine whether the chilling treatment affected lipid composition and content. A slight decrease of sterol lipid/glycerophospholipid ratio was observed in CT seedlings, and although the levels of unsaturated fatty acids in phosphatidylglycerol were not significantly different between the two seedlings, the level of 3-E-hexadecenoic acid increased slightly in CT seedlings. In phosphatidylcholine, the level of linolenic acid slightly increased in the CT seedlings. In ceramide monohexoside, the levels of 8-Z- and 8-E-stereoisomerism of 4-hydroxy sphingoid bases were essentially the same between the two seedlings, while a slightly increased level of 2-hydroxy palmitic acid was observed in CT seedlings. The involvement of lipids in the change to chilling sensitivity is discussed in this experiment
