冬季异常高温对亚热带地区树木休眠解除的影响

[Objective]Cold accumulation in winter is the main factor affecting tree dormancy release.Under the influence of global warming,the occurrence frequency of abnormal high temperature in winter increases,especially in subtropical regions where abnormal high temperature is often 20℃or above in winter.However,the existing cold accumulation model is based on the characteristics of the temperate climate,the temperature in the temperate region is low in winter,and it is unable to truly and accurately identify and deal with this abnormal high temperature,resulting in the model cannot be fully applicable to subtropical tree species.Under the background of climate warming,the effect of abnormal high temperature in winter on the dormancy release of subtropical tree species and how to deal with such abnormal value in cold accumulation model need to be studied urgently.Cold accumulation in winter is the main factor affecting tree dormancy release.Under the influence of global warming,the occurrence frequency of abnormal high temperature in winter increases,especially in subtropical regions where abnormal high temperature is often 20℃or above in winter.However,the existing cold accumulation model is based on the characteristics of the temperate climate,the temperature in the temperate region is low in winter,and it is unable to truly and accurately identify and deal with this abnormal high temperature,resulting in the model cannot be fully applicable to subtropical tree species.Under the background of climate warming,the effect of abnormal high temperature in winter on the dormancy release of subtropical tree species and how to deal with such abnormal value in cold accumulation model need to be studied urgently.[Method]In order to explore the response of tree species in subtropical regions to the abnormal high temperature in winter,Torreya grandis,Sassafras tzumu,Torreya grandis,Sassafras tzumu,Cinnamomum camphora,Phoebe chekiangensis,Castanopsis sclerophylla,Ginkgo biloba L,Carya illinoinensis,Pseudolarix Kaempferi(Lindl)Gord and other tree species in subtropical areas were used as test materials,and five different accumulation and cooling treatments were used(the accumulation and cooling time were all 66d):Constant low temperature at 4℃,natural low temperature in winter,and high temperature(20℃,simulating abnormal high temperature in winter caused by climate warming)at different stages of accumulation of constant low temperature at 4℃(1w,4w,7w)were treated for a period of time,and then the seedlings were transferred to accumulated temperature climate chamber(20℃)to observe the germination and leaf spread.[Conclusion]Abnormal high temperature actually plays the role of temperature accumulation in the process of cold accumulation,and the temperature accumulation and cold accumulation interact and synchronize.This study revealed the effects of abnormal high temperature in winter on dormancy of subtropical trees and its effects in different stages of dormancy release,which can provide scientific basis for optimizing the existing cold accumulation model.