木本植物木质部的冻融栓塞应对研究进展  

Research progress on responses of xylem of woody plants to freeze-thaw embolism

作　　者：李志民 王传宽[1,2] LI Zhi-Min;WANG Chuan-Kuan(Center for Ecological Research,Northeast Forestry University,Harbin 150040,China;Ministry of Education Key Laboratory of Sustainable Forest Ecosystem Management,Northeast Forestry University,Harbin 150040,China)

机构地区：[1]东北林业大学生态研究中心,哈尔滨150040 [2]森林生态系统可持续经营教育部重点实验室,哈尔滨150040

出　　处：《植物生态学报》2019年第8期635-647,共13页Chinese Journal of Plant Ecology

基　　金：国家重点研发计划(2016YFD0600201);教育部长江学者和创新团队发展计划(IRT_15R09)~~

摘　　要：冻融栓塞在中高纬度地区木本植物中普遍存在。抗冻融栓塞能力对在寒冷环境中木本植物的生长和安全越冬十分关键,这直接决定植物分布范围。冻融栓塞是由于冰中气体溶解度低,木质部水分在低温下冷冻,使之前水中溶解的气体逸出到导管中,随后木质部中的冰融化又使气泡扩张而引发的栓塞现象。木质部解剖结构的差异会影响植物的抗冻融栓塞能力,植物还可以通过调节木质部正压、代谢耗能等方式主动修复冻融栓塞,也可通过增加树液溶质含量等逃避冷冻,以减少低温损伤。然而,与干旱栓塞相比,目前对木质部冻融栓塞的形成以及植物响应和调节机制的理解不足。为此,该文首先综述了木质部冻融栓塞的形成机制和植物的逃避、忍耐、修复等3种冻融栓塞的应对策略,然后总结了木质部抗低温胁迫能力的生理表现、影响因子和评价指标,并在此基础上讨论了低温抗性、干旱抗性和水力效率之间的多元权衡关系,最后提出今后该领域中的5个优先研究问题:(1)不同植物冰冻的最低温度阈值;(2)是否存在应对低温胁迫的水力脆弱性分割机制;(3)冻融栓塞修复与代谢消耗的关系;(4)低温抗性、干旱抗性和水力效率之间的权衡关系;(5)抗冻融栓塞性状是否能够纳入经济性状谱系。Embolism induced by the freeze-thaw commonly occurs in the woody plant in mid-and high-latitude regions. In cold environments, the resistance capacity to freeze-thaw embolism of woody plants is critical for their growth and successful survival throughout winter, which directly determines their distribution in the earth. During freeze-thaw cycles, the freeze-thaw embolism of vessels is induced by the bubbles that are from dissolved frozen water because of the low solubility of ice. The resistance capacity to freeze-thaw embolism varies from plants with different anatomical structures. Plants can also reduce potential damages of freeze-thaw embolism through adjusting the xylem positive pressure by refilling embolism and metabolism, and/or increasing the sap solute contents to avoid the stress. Compared to embolism induced by drought, however, few studies have been conducted on embolism by freeze-thaw, and the underlying mechanisms of plant responses and regulation are poorly understood. In this paper, we first reviewed the process of formation and repair of freeze-thaw embolism of xylem, including the strategies of escaping freezing, tolerance, and repairing freeze-thaw cavitation. Then we summarized physiological characteristics of plant resistance to low-temperature stress, influencing factors and evaluating criteria, based on the multiple trade-offs between low-temperature resistance, drought resistance, and hydraulic efficiency. Finally, we proposed five priorities for future study in this field:(1) the threshold of freezing temperature for different plants;(2) the vulnerability segmentation of frost-induced embolism;(3) the relationships between freeze-thaw cavitation repair and metabolism exhaustion;(4) the potential trade-offs between low-temperature resistance, drought resistance and hydraulic efficiency;and(5) integration of the traits of freeze-thaw embolism resistance into the economic spectrum of plants.

关 键 词：冻融栓塞 栓塞修复 水力效率 权衡 水力特征 

分 类 号：Q945[生物学—植物学]