摘要
许多树木管状分子细胞的细胞壁在冰冻期间并不随细胞内的水分迁移到细胞外冰晶上而塌陷。此时细胞内产生负压 ,负压的产生引起腔隙的形成 ,腔隙又会引起栓塞 ,导致树木内水分运输受阻。冻融循环可导致腔隙和栓塞的形成 ,或者冰冻之后 ,温度急剧回升时树木组织内的冰晶升华所致。在春季树木的根压得到恢复 ,从而使腔隙和栓塞部分消除 ,水分运输又得以畅通。冰冻胁迫对在高纬度和中高纬度的某些地区的树木的生长造成很大的危害 ,管状分子内腔隙和栓塞的形成就是其中之一 ,也是引起树木生长衰退或死亡的主要原因。本文对腔隙和栓塞的形成的原因、机理及其恢复进行了综述。
Cell wall of treacheary elements in some trees does not collapse as the cellular_water migrates to the extracellular ice during freezing, thus negative pressure comes up in cells. Negative pressure induce cavitation, and it results in embolism. Therefore, water transport is blocked in trees. Development of cavitation and embolism is regarded as the result of freeze_thaw cycles or of ice sublimation in some tissues when temperature rises fast after freezing. Root pressure forms again during vernal season, and cavitation and embolismare repaired in part. So water transport in trees isn't blocked too. Freezing stress results a great injury of trees in high latitude and some areas of mid_ high latitude. Cavitation and embolism in xylem treacheary elements are a kind of injury induced by freezing stress, and also the main reason that result in growth declines or death of trees. The paper reviews the causes of formation of cavitation and embolism, its mechanism and repair.
出处
《植物学通报》
CAS
CSCD
北大核心
2001年第1期58-63,共6页
Chinese Bulletin of Botany
基金
国家"九五"科技攻关项目! ( 96_0 1 1_0 2_0 1 )