EXTRACELLULAR FREEZING IN EQUISETUM HYEMALE
EXTRACELLULAR FREEZING IN EQUISETUM HYEMALE
复制标题
木贼属细胞外冷冻
DOI：
--
复制
发表时间：
1989
期刊：
影响因子：
--
通讯作者：
K. Niklas
中科院分区：
文献类型：
--
作者：
K. Niklas
木贼髓腔内发生细胞外冻结。当它们暴露在低于冰点的温度下时，会产生气生芽。髓腔内冰塞的重量与髓间组织的重量呈线性相关（r ~ 2 = 0.974，N = 10），冰塞的平均重量为32-38%（33？1.8%。解冻后，节间的水分逐渐被切下的枝条重新吸收。细胞外冷冻可以通过将切除的枝条暴露于逐渐降低的温度（5 ℃/天）至-20 ℃来诱导，并且与组织水势的降低有关。数据表明，节间组织表现为渗透压计和渗透压计，直到达到平衡与细胞外液的化学势intermodal髓腔。解冻后，间隙水被切下的枝条重吸收，组织水势增加。细胞外冷冻可以作为一种机制，减少细胞内冰的形成和组织损伤在极端寒冷的天气。
Extracellular freezing occurs within the pith cavities of Equisetum hyemale L. aerial shoots when they are exposed to subfreezing temperatures. The weight of plugs of ice within pith cavities correlates linearly with the weight of intemodal tissues (r2 = 0.974, N = 10); ice plugs are 32-38% (33 ? 1.8%) the weight of intact shoots. Upon thawing, internodal water is gradually reabsorbed by excised shoots. Extracellular freezing can be induced by exposing excised shoots to gradually decreasing temperatures (5 C/day) to - 20C, and is associated with a reduction in tissue water potential. Data indicate that internodal tissues behave as osmometers and dehydrate until reaching equilibrium with the chemical potentials of extracellular fluids within intemodal pith cavities. Upon thawing, intemodal water is reabsorbed by excised shoots and tissue water potential increases. Extracellular freezing may operate as a mechanism that reduces intracellular ice formation and tissue damage during extremely cold weather.