栽培时间对香樟半致死温度及抗寒性的影响

Effects of Cultivation Time on Semi-lethal Temperature and Cold Resistance Evaluation of Cinnamomum camphora

为探索引种栽培对香樟(Cinnamomum camphora(L.)Presl.)抗寒性变化的影响,保证香樟安全越冬,在低温胁迫时,观察香樟形态特征,并测定相对电导率的变化,利用逻辑斯蒂(Logistic)方程拟合相对电导率与温度之间的函数关系,计算出香樟半致死温度,根据半致死温度采取相应的抗寒栽培措施。结果表明:①从形态学观察发现,胁迫温度高于-10℃时,香樟未有冻害发生,叶片和枝条均为绿色;在-10℃时,香樟枝条和叶片冻害形态变化有明显差别,叶片萎蔫且由绿色变为褐色,皮层变为褐色,变褐色的程度从大到小依次为栽培时间1、5、10、15 a,横切面髓部、木质部完好;在-15℃时,所有香樟枝条都表现为严重冻害,栽培1、5、10、15 a的香樟冻害指数分别为78.94%、72.36%、68.65%、61.36%,随着栽培时间的增加,冻害指数不断降低;-20℃时,所有枝条发生不可逆冻害,冻害指数均为100%。②随着栽培时间的增加,相同胁迫温度的香樟相对电导率下降,呈近似“S”形曲线,栽培1、5、10、15 a的香樟半致死温度分别为-10.26、-11.04、-11.63、-12.39℃,栽培15 a香樟较1 a香樟半致死温度降低了2.13℃。因此,驯化栽培可以提高植物的抗寒性,根据半致死温度采取抗寒栽培措施,可减少香樟冻害的发生。

To explore the effect of introduction and cultivation on the cold resistance of Cinnamomum camphora(L.)Presl.,the morphological characteristics and relative conductivity of C.camphora under low temperature stress were studied,the semi-lethal temperature of C.camphora was fitted by Logistic equation to fit the functional relationship between relative conductivity and low temperature,and the corresponding cold-resistant cultivation measures were taken according to the semi-lethal temperature.The results showed that:(1)the stress temperature was above-10℃,the leaves and branches of C.camphora were green,and no freezing injury occurred,the morphological changes of branches and leaves of C.camphora were obviously different from each other,the leaves wilted and turned brown from green,the cortex turned brown and the degree of turning brown was 1,5,10 and 15 a in the descending order.At-15℃,all the branches of C.camphora showed severe freeze injury with the freeze injury indexes of 78.94%,72.36%,68.65%and 61.36%,respectively,and the frost injury index was decreased continuously.When the temperature was-20℃,all branches were damaged irreversibly,and the frost injury index was 100%.(2)With the increase of cultivation years,the electrical conductivity of C.camphora decreased under the same stress temperature,which showed an approximate“S”curve.The fitting semi-lethal temperatures of C.camphora under were-10.26,-11.04,-11.63 and-12.39℃,respectively,and the semi-lethal temperature of C.camphora decreased by 2.13℃.Acclimated cultivation can improve the cold resistance of plants,and take cold-resistant cultivation measures according to the semi-lethal temperature to reduce the occurrence of freezing injury of C.camphora.