摘要：AbstractObjectivesThe living stems ofIsodon rubescens(Hemsley) H. Hara peels and withers when the air temperature is below 0 °C in winter. The peels and withers evidently hamper the growth ofI. rubescens. This report analyses the reason that causesI. rubescensstems to peel and wither in winter.MethodsThe field investigation and paraffin sections ofI. rubescensstems (peeled and intact) were performed.ResultsThe results showed thatI. rubescensstems extruded ice ribbons at air temperature below 0 °C. The enlarged ice ribbons separated the phloem from the xylem, burst the phloem and even the whole bark of theI. rubescensstems.ConclusionsThe phloem was separated from the xylem by the enlarged ice ribbons. The phloem and the whole bark of theI. rubescensstems were torn when ice ribbons appeared. The damaged stem could not transport water and nutrition to the upper section. The upper stem above the ice ribbons withered because it could not receives water and nutrition.
