抄録
The size of micro-capillaries within cell walls of xylem parenchyma cells of woody plants has been estimated by the plasmolysis method using hypertonic solutions consisted of various size of molecules ranging from 0.8 nm to 5.2 nm. All xylem parenchyma cells examined, including xylem ray parenchyma cells exhibiting typical deep supercooling to -40℃, produced distinct plasmolysis by treatment with these all hypertonic solutions, indicating that size of cell wall micro-capillaries in xylem cells exceeded more than 5.2 nm. Water located in cell wall micro-capillaries in size larger than 5.2 nm cannot supercool at least below -20℃. Thus, it is suggested that the cause of deep supercooling of xylem parenchyma cells in woody plants cannot be explained solely by structural property of cell walls in relation with the size of micro-capillaries.
