Kasuga Jun, Takata Naoki, Yamane Kenichi, Kuroda Katsushi, Arakawa Keita, Fujikawa Seizo
Laboratory of Woody Plant Biology, Hokkaido University, Sapporo, Japan.
Cryo Letters. 2007 Mar-Apr;28(2):77-81.
In previous studies, xylem parenchyma cells (XPCs) in the boreal softwood species larch, which has thick and rigid walls similar to those of XPCs in boreal hardwood species, were shown to respond to subfreezing temperature by deep supercooling during summer but change their freezing behavior to extracellular freezing during winter. In this study, we re-examined freezing behavior of XPCs in larch by observation of deep etching of frozen samples as well as observation of re-warmed samples after freezing using a cryo-scanning electron microscope. The results showed that XPCs in larch adapts to subfreezing temperature by deep supercooling throughout all seasons. Such freezing behavior is the same as that of XPCs in boreal hardwood species.
在先前的研究中，北方针叶林软木树种落叶松中的木质部薄壁细胞（XPCs），其细胞壁与北方硬木树种的XPCs一样厚且坚硬，研究表明这些细胞在夏季通过深度过冷却来应对亚冰点温度，但在冬季其结冰行为会转变为细胞外结冰。在本研究中，我们通过对冷冻样品的深度蚀刻观察以及使用低温扫描电子显微镜观察冷冻后复温的样品，重新研究了落叶松中XPCs的结冰行为。结果表明，落叶松中的XPCs在所有季节都通过深度过冷却来适应亚冰点温度。这种结冰行为与北方硬木树种中XPCs的结冰行为相同。
