常绿阔叶树种的耐低温特性及其生态学评价  

Low-temperature tolerance characteristic and ecological evaluation of broad-leaved evergreen tree species

作　　者：谢晓金[1] 郝日明[1] 张纪林[2] 

机构地区：[1]南京农业大学园艺学院,南京210095 [2]江苏省林业科学研究院,南京211153

出　　处：《生态学报》2004年第11期2671-2677,共7页Acta Ecologica Sinica

基　　金：国家林业局"948"资助项目 ( 2 0 0 1-5 9-0 1)~~

摘　　要：选取在南京地区已露地引种的 2 4种常绿阔叶树种 ,其自然分布北界止于亚热带不同的纬度 ,运用生理生态方法 ,测定它们在模拟低温处理下的电导率 ,并结合寒冷指数和引种后其适应性表现 ,分析这些树种的耐低温能力。结果表明 ,以某一树种自然分布北界气象资料为依据的寒冷指数与其自然植被的水温条件关系更为密切 ,寒冷指数有时不能反映树种本身耐低温能力的高低。如乐东拟单性木兰 ,其自然分布于亚热带南部 2 6°N,引种到南京耐低温表现明显好于自然分布于亚热带北部的香樟。而采用低温循环仪自动降温程序模拟冰冻处理来测定离体叶片的相对电导率 ,计算出各常绿阔叶树种叶片的半致死温度 ,能定量地反映这些树种本身的耐低温能力高低。在测试中如借助已知耐低温能力的树种作对照 ,其数据结果可作为常绿园林阔叶树种能否向更高纬度引种的重要参考依据。在上述研究基础上选出 6种 ,以其离体叶片为试材 ,测定其可溶性糖和游离脯氨酸含量 ,结果显示 ,随处理温度的降低 ,可溶性糖和游离脯氨酸的含量呈增加趋势 ,然而只有在适宜的处理下才呈现规律性变化 ,这些研究结果可作为树种耐低温能力的定性补充证据。Three eco-physiological characteristics including electric conductivity under lower temperature treatment, coldness index and adaptability of growth were used to analysis the ability of 24 broad-leaved evergreen tree species to withstand the rigors of cold temperature. These plants which naturally distributed over the north limit of differently subtropical latitude were introduced to the open in Nanjing. It is found that coldness index based on the meteorological records of the north limit of their natural habitats is closely related to climate condition of natural vegetations, but is not tightly correspondent to their low temperature tolerance. The best example is that the hardness of Parakmeria lotungensis in Nanjing was stronger than that of Cinnamomum camphora which naturally distributed over the north of subtropical area, although the former naturally distributed over 26° N south of subtropical area. Electric conductivities of excised-leaves under simulated freezing treatment were measured and lethal temperature 50(LT50) were calculated. The results could correctly indicate the low temperature tolerance of these tree species in quantitative determination. They are also important indexes to introduce new broad-leaved evergreen tree species to higher latitude by comparing with the tree species of known adaptabilities. Six species selected from 24 broad-leaved evergreen tree species were chosen to measure the contents of soluble sugars and proline in excised-leaves. The results show that the contents of soluble sugars and proline were increased under the proper conditions as the temperature was decreased, suggest that they could be supplementary characteristics of the low temperature tolerance. Altogether the research results demonstrate high value to predict the low temperature tolerance of broad-leaved evergreen tree species and provide the best clue as to the potential usefulness of that species in its new habitat.

关 键 词：常绿树种 耐低温特性 寒冷指数 电导法 

分 类 号：Q945[生物学—植物学]