【作者】 李刚；

【导师】 姜卫兵；

【作者基本信息】 南京农业大学 ， 果树学， 2006， 硕士

【摘要】 近年来，随着社会经济的高速发展和人们生活水平的日益提高，城市园林绿化事业方兴未艾，为园林植物的应用提供了更加广阔的舞台。由于地理、气候等条件的限制，北方城市的园林树种以落叶树为主，在漫长的冬季城市景观萧条，缺乏生机勃勃的绿色，同时城市生态环境也得不到有力的改善。随着全球气候变暖，城市多样性的小气候条件也为常绿植物提供了适宜的生长场所，因此，选择一些生态、观赏价值高的常绿园林树种引种、驯化、应用到北方城市受到政府部门和研究学者的广泛关注和重视，显示出良好的发展势头。 由于引种植物的原生境和引种地区的地理、气候等环境差异比较大，影响引种植物安全正常生长的因子也是多方面的，冬季低温和夏季高温成为限制引种的关键限制因子。目前关于常绿树种在北亚热带范围冬春季节的抗寒生理和光合生理生态特征研究还很少。本研究以原产于中亚热带以南地区、园林绿化应用前景广阔的几种木兰科常绿树种为材料，测定其抗寒能力，探讨其在冬季的抗寒生理变化以及冬春季节的光合日变化、光合特性、荧光日变化等。结果表明： 1 越冬期间木兰科常绿树种抗寒生理变化的研究 (1) 经过一段时期的低温锻炼后使供试树种抗寒能力增加，但中亚热带树种的提高要大于南亚热带树种，表现为中亚热带树种的冻害指数和半致死温度均要低于南亚热带树种，抗寒性排序为：乐东拟单性木兰(Parakmeria lotungensis)＞阔瓣含笑(MicheliaPlatypetala)＞金叶含笑(Michelia foveolata)＞红花木莲(Manglietia insignis)＞醉香含笑(Michelia macclurei)＞观光木(Tsoongiodendron odorum)。(2) 越冬期间所有树种的MDA含量均显著上升，表明因低温引起的膜脂过氧化作用加重，到冬末又均明显下降，此时供试树种的SOD活性均明显升高，对保护细胞膜系统起到了一定的作用，而POD活性则持续降低，受低温胁迫影响较大。(3) 越冬期间所有树种的叶绿素a含量均明显下降，受到了低温破坏，而叶绿素b的含量变化比较复杂，3个中亚热带树种的类胡萝卜素含量在越冬期间显著升高，明显高于3个南亚热带树种，这对保护细胞膜系统、提高抗寒能力可能有用。 2 冬春季节木兰科常绿树种的光合生理生态研究更多还原

【Abstract】 With the development of social economy and pepole’s lives, the gardening of cities had prospered lushly, which provided expansive arena for the use of gardening species. Because of the limination in geology and climate, the northern cities were most composed by hardwood which leaded the stagnancy of winter scenery and the lack of good ecological environment. By the warming of temperature in the world, the diversities of small climate in city also provided the good location for evergreen species. That was to say, we should attach much importance to the appliance of evergreen species in the northern cities.Other wise, because of the total environmental genes’s limination, there were many factors influence the safy of species, the key factors were low temperature in winter and high temperature in summer. For the moment, there were few researches about the chilling physiologic and photosynthetic characteristics of evergreen species in winter and spring in the northern-tropical area. This article studied the photo-ecological and chlorofluorescence characteristics in winter and spring of several evergreen species. The results showed:1 The performance and the physiological variation of evergreen species in winter(1) The magnolia species that distributed naturally in northern-subtropical areas had much lower TL50 than that distributed naturally in sourthern-subtropical areas. The chilling resistance abilities of six magnolia species were : Parakmeria lotungensis> Michelia Platypetala > Michelia foveolata > Manglietia insignis > Michelia macclurei > Tsoongiodendron odorurn. (2)All species’ contents of MDA ascended during the course of winter and descended at the end of winter. All species’ activities of SOD ascended during the course of winter thus to protect the cell, while the activities of POD descended all the time which manifested that it suffered strong breakage in winter.(3) All species’ contents of Chl a descended during the course of winter while Chl b varied complicated, three magnolia species that distributed naturally in northern-subtropical areas had much more Car than the other three species during the course of winter, that was probably a good way to protect the cell from cold menace in winter.2 The photo-ecological characteristics of evergreen species in winter and spring(1) The five species’ diurnal variation tapes of Pn and WUE in winter were different更多还原