Freezing behavior of xylem ray parenchyma cells in softwood species with differences in the organization of cell walls
Freezing behavior of xylem ray parenchyma cells in softwood species with differences in the organization of cell walls
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DOI：
10.1007/bf01279251
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发表时间：
1999-01-01
期刊：
影响因子：
2.9
通讯作者：
Ohtani, J
中科院分区：
文献类型：
--
作者：
Fujikawa, S;Kuroda, K;Ohtani, J
通过低温扫描电镜，我们研究了不同软木种类的木质部射线薄壁细胞细胞壁组织对冷冻行为的影响，即过冷和细胞外冷冻的能力。细胞壁组织的明显差异与冻结行为的差异有关。木质部射线薄壁细胞具有薄且未木质化的初生壁，在整个区域（松木的所有细胞和密松的未成熟细胞）或大部分区域（密松的成熟细胞和异花松的所有细胞）对冷冻条件的反应是细胞外冷冻，而木质部射线薄壁细胞具有厚且未木质化的初生壁。大多数地区木质化的初生壁（日本冷杉的所有细胞）或次生壁（落叶松的所有细胞）对过冷的冷冻反应。尽管细胞壁组织没有明显的变化，但木质部射线薄壁细胞的冻结行为从夏季的过冷到冬季的细胞外冻结有季节变化。这些结果表明，木质部射线薄壁细胞的冻结行为不仅与细胞壁组织的明显差异平行，而且与细胞壁结构的细微亚电子显微镜差异平行。
By cryo-scanning electron microscopy we examined the effects of the organization of the cell walls of xylem ray parenchyma cells on freezing behavior, namely, the capacity for supercooling and extracellular freezing, in various softwood species. Distinct differences in organization of the cell wall were associated with differences in freezing behavior. Xylem ray parenchyma cells with thin, unlignified primary walls in the entire region (all cells in Sciadopitys verticillata and immature cells in Pinus densiflora) or in most of the region (mature cells in P. densiflora and all cells in P. pariflora var. pentaphylla) responded to freezing conditions by extracellular freezing, whereas xylem ray parenchyma cells with thick, lignified primary walls (all cells in Crytomeria japonica) or secondary walls (all cells in Larix leptolepis) in most regions responded to freezing by supercooling. The freezing behavior of xylem ray parenchyma cells in L. leptolepis changed seasonally from supercooling in summer to extracellular freezing in winter, even though no detectable changes in the organization of cell walls were apparent. These results in the examined softwood species indicate that freezing behavior of xylem ray parenchyma cells changes in parallel not only with clear differences in the organization of cell walls but also with subtle sub-electron-microscopic differences, probably, in the structure of the cell wall.