不同低温胁迫对南京10种道路绿化树木形态及电导率的影响

为了揭示常见道路绿化树种抗寒能力,运用形态观察法分析南京10种绿化树种在越冬期间叶片冻害状况,同时,运用相对电导率法测定不同绿化树种的半致死温度并进行综合分类,结果表明:第1类是海桐、广玉兰和撒金珊瑚,它们的叶片多数表现为无冻害或轻微冻害,半致死温度分别为-19.60、-18.83、-18.21℃,抗寒性最强;八角金盘、桂花、红花檵木是第2类,它们的半致死温度分别为-10.78、-10.45、-9.71℃,叶片多表现为轻微冻害或无冻害,抗寒性强;第3类为香樟和小叶黄杨,其叶片多为轻微、轻度甚至中度冻害,半致死温度分别为-15.40、-7.88℃,它们的抗寒性中等;法国冬青和女贞为第4类,其半致死温度分别为-7.88、-5.63℃,法国冬青的叶片多为中度、轻度冻害,女贞为轻度或轻微冻害,它们的抗寒性弱。

Effects of Low Temperature Stress on Morphological and Electrical Conductivity of Ten Species of Afforestation Trees Along Road Sides in Nanjing

Morphological observation was performed to analyze the freezing injury of leaves of 10 species of afforestation trees in Nanjing during winter in order to reveal the anti-frigidity of common tree species along road sides.Relative electrical conductivity was applied to measure the semi-lethal temperature(LT50) of different tree species.The afforestation tree species were classified according to morphological characteristics and LT50.Results indicate that the first category includes Pittosporum tobira,Maqnolia grandiflora,and Aucuba japonica var.variegate,whose leaves suffered light or no freezing injury.LT50 values of P.tobira,M.grandiflora,and A.japonica var.variegate are-19.60,-18.83,and-18.21 degrees C,respectively,and their properties of anti-frigidity are the best.Fatsia japonica,Osmanthus fragrans,and Loropetalum chinense belong to the second category,whose LT50 values are-10.78,-10.45,and-9.71 degrees C,respectively.The leaf surface of F.japonica,O.fragrans,and L.chinense appeared light or no freezing injury,and their properties of anti-frigidity are relatively good.Cinnamomum camphora and Buxus sinica are in the third category,whose leaves suffered light,mild or moderate freezing injury.The LT50 values of C.camphora and B.sinica are-15.40 and-7.88 degrees C,respectively,and their properties of anti-frigidity are moderate.Viburnum awabuki and Ligustum lucidum belong to the fourth category,and the LT50 values are-7.88 and-5.63 degrees C,respectively.The leaves of V.awabuki exhibited moderate or light freezing injury,while the leaves of L.Lucidum appeared mild or light freezing injury,and their properties of anti-frigidity are the worst.