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林业科学 ›› 2018, Vol. 54 ›› Issue (9): 38-43.doi: 10.11707/j.1001-7488.20180905

• 论文与研究报告 • 上一篇    下一篇

常绿园林植物顶花板凳果叶片低温条件下的结冰模式分析

解卫海, 王仲礼, 朱建军   

  1. 鲁东大学生命科学学院 烟台 264025
  • 收稿日期:2017-08-09 修回日期:2017-09-28 出版日期:2018-09-25 发布日期:2018-09-10
  • 基金资助:
    国家自然科学基金项目(31371540,31260080)和山东省自然科学基金项目(ZR2012CM007)。

On the Freezing Mode of Leaves of an Evergreen Ornamental Plant Pachysandra terminalis under Low Temperatures

Xie Weihai, Wang Zhongli, Zhu Jianjun   

  1. College of Life Sciences, Ludong University Yantai 264025
  • Received:2017-08-09 Revised:2017-09-28 Online:2018-09-25 Published:2018-09-10

摘要: [目的]分别用热力学和显微观察分析常绿植物顶花板凳果结冰过程的胞外结冰,以了解该种常绿植物叶片的结冰模式,为阐明常绿植物抗冻机制提供理论依据。[方法]用高分辨率差热扫描分析模式植物叶片结冰过程中的热力学行为,同时用显微镜观察植物叶片组织的结冰特征。[结果]高分辨率差热扫描法监测到顶花板凳果活叶片在冷却过程中出现双放热峰,呈现双相结冰和细胞外先结冰的特征,而预先冰冻杀死的叶片和叶片组织提取液仅有1个快速的单放热峰,呈现单相均一溶液结冰,即细胞内外同时结冰的特征。活叶片的结冰弛豫时间为195秒,过冷度为5.05℃,冰冻杀死叶片的结冰弛豫时间为73 s,过冷度为5.45℃。由显微观察可知,细胞间隙中细胞间隙溶液形成大体积的无色冰晶。[结论]顶花板凳果叶片组织在冷却过程中的胞外结冰现象。同时,本研究提供了高分辨率差热分析植物叶片结冰模式的方法。该结果为从热力学角度进一步深入了解植物的冰冻伤害机制提供新的途径。

关键词: 顶花板凳果, 冰冻胁迫, 差热分析, 胞外结冰

Abstract: [Objective] The freezing mode,namely intercellular or intracellular freezing, in an evergreen plant Pachysandra terminalis. was investigated with the differential thermal analysis and light microscopy.[Method] This study employed differential thermal analysis and microscopic observations to seek evidence of extracellular freezing in P. terminalis Sieb. et Zucc. duiring cooling and freezing.[Result] High resolution differential scanning calorimetry was used to detect the evidence of extracellular freezing in the P.terminalis leaves.The living leaves of the plants consistently exhibited biphasic freezing exotherms, i.e., an initial small exotherm followed by a slow but much larger exotherm. In contrast, the freeze-killed leaves, as well as the filter paper drenched with extracted tissue solutions from the leaves of the two plants, exhibited just one fast and large exotherm typical for a single phase freezing. The relaxation time of the freezing course was 195 seconds for the living leaves, and 73 seconds for the killed leaves; the supercooling degree was 5.05℃ for the living leaves and 5.45℃ for the freeze killed leaves. Colourless ice crystals were observed in the intercellular spaces in the living leaves, and however coloured ice crystals in killed leaves with a microscope, which was in agreement with the result from the differential thermal analysis.[Conclusion] Although differential thermal analysis has been used in analysing the phase change temperature and the saturation degree of membrane lipids, reports on the use of the technique in analysing the freezing mode of plant tissues has not yet been seen. The experiment provided another new approach to the researches on the mechanisms of freezing injury to plants.

Key words: Pachysandra terminalis, freezing stress, differential thermal analysis, extracelluar freezing

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