【作者】 余焜；

【导师】 陈伏生；

【作者基本信息】 南昌大学 ， 园林植物与观赏园艺， 2010， 硕士

【摘要】 叶属性,如叶重比和C、N、P含量及化学计量比直接关系到植物的C同化、养分利用和能量平衡等各种生态生理功能,与植物的生态适应关系密切,对于指导城市园林的植物选择、群落配置和生态管理具有重要的意义。本研究以位于南昌市郊中亚热带丘陵红壤区的南昌大学前湖校区16种主要园林植物为研究对象,动态监测土壤养分供应能力、叶面积、叶质量、叶C、N、P含量,凋落叶养分含量,并换算出叶重比、植物养分再吸收效率等指标,分别以植物种类、植物功能群、群落结构类型、校园功能区等为划分标准,进行数据统计和对比研究。主要结论如下：(1)不同植物种类和不同植物功能群的土壤有机C、全N、全P含量差异均不显著,说明本研究选取植物的土壤养分含量的基本状况比较一致。而土壤铵态N、硝态N和矿质N既有明显的季节波动规律,还受植物种类、植物功能群、群落结构类型、校园功能区的影响,土壤供N能力是土壤与植物相互作用的结果。(2)不同植物种类、植物功能群和群落结构类型之间叶重比差异显著(P<0.05,以下同),具体表现为：桂花≥广玉兰≥香樟=含笑≥紫荆=杜鹃=桃树=柳树=鹅掌楸；常绿阔叶乔木>灌木=落叶阔叶乔木；乔草型≥灌草型=乔灌型≥纯灌型=纯乔型；而位于校园不同功能区植物的平均叶重比差异不显著。(3)不同植物种类和植物功能群叶全N含量的年均值差异显著,而不同群落结构类型和校园功能区植物叶全N含量的年均值差异不显著；不同植物种类、植物功能群和群落结构类型叶全P含量的年均值差异均显著,而不同校园功能区叶全P含量的年均值差异不显著；叶C／N表现为不同植物种类、植物功能群、群落结构类型和校园功能区均存在显著差异,而叶N／P仅表现为不同植物种类和不同植物功能群之间的差异,而不同群落结构类型和不同校园功能区之间显著均不差异。推断叶养分受多重因子,如植物遗传性状、土壤养分供应、外界环境因子等的调控,且影响叶N和P含量的主导因子有别。(4)养分再吸收力主要受植物种类、植物功能群、群落结构类型的影响,而与校园功能区无关；养分再吸收效率主要受植物种类和植物功能群的影响,而与群落结构类型和校园功能区无关。可见,养分再吸收主要受植物本身的属性决定。(5)植物叶重比与春、夏、秋、冬叶全N含量及年均值、N再吸收力之间均呈负相关,与N再吸收效率不相关；与春、夏季叶全P含量及年均值、P再吸收效率之间均负相关,与秋、冬季叶全P含量、P再吸收力不相关。这表明N限制植物的生长要强于P,且植物对P的限制性具有较强的适应能力。综合来看,叶结构和营养特性主要是由植物本身的遗传性状所决定的,且叶重比、叶N、P营养特性的生态适应机制表现为不同步性。继续深入地开展相关的基础研究,可以为园林植物的选择、群落配置、生态管理提供可靠的依据。更多还原

【Abstract】 Leaf traits including leaf mass per area (LMA), C, N, P concentrations and their ratios are directly related with many ecological and physical functions, such as plant’ C assimilation, nutrient use and energy balance. Additionally, leaf traits are closely related with plant ecological adaption, which is very useful to plant selection, community allocation, and ecological management in urban garden. We selected 16 garden plants to study their soil nutrients, leaf area, leaf mass, leaf C, N, and P concentrations, litterfall nutrient concentrations in Qianhu campus of Nanchang university, which located at suburban of Nanchang city, mid-subtropical hilly red soil region. Therefore, we compared the differences in LMA, leaf nutrient concentrations, plant nutrient resorption among different groups based on plant species, functional grouping, community structure type and campus functional area. Major conclusions as follows:(1) Soil organic C, total N and total P were not significant differences among either among 16 species or among six functional groupings, which showed similar soil nutrient status for all selected plants. However, the concentration of soil NH4+-N, NO3--N, mineral N were influcenced by season, plant species, functional grouping, community type and campus functional area. Thus, soil N supply was interacted by soil and plant.(2) Significant differences in LMA (P<0.05) were found among nine species (Osmanthus fragrans≥Magnolia grandiflora≥Cinnamomum camphora=Michelia figo≥Cercis chinensis= Rhododendron simsii= Prunus persica= Salix babylonica= Liriodendron chinese), three functional grouping (Evergreen broadleaved trees> Shrubs= Hardwoods) and five community types (Tree+herb> Shrub+herb= Tree+shrub> Shrub=Tree), while there was not significant differences among five campus functional areas.(3) The average concentrations of leaf N were significant differences among 16 species and six functional groupings, while no significant differences among five community structure types and five campus functional areas. The average concentrations of leaf P were significant differences among 16 species, six functional groupings and five community types, while no significant differences among five campus functional areas. The average values of leaf C/N were significant differences among 16 species, six functional groupings, five community structure types and five campus functional areas. The average values of leaf N/P were significant differences among 16 species and six functional groupings, while no significant differences among five community types and five campus functional areas. Therefore, leaf nutrient traits were influenced by multiple factors, such as plant genetic characteristics, soil nutrient conditions and ecological factors. Additionally, leaf N and P concentrations would be controlled by different limiting factors.(4) Nutrient resorption proficiencies were influenced by plant species, functional grouping, community structure type, and not related with campus functional area. Nutrient resporption efficiencies were influenced by plant species, functional grouping and campus functional area, and not related with community structure type. Thus, nutrient resorption depended on plant traits themselves.(5) LMA was negative related with leaf N concentrations in spring, summer, autumn, winter and average values, plant N resorption proficiency, leaf p concentrations in spring, summer and average values across four season, plant resorption efficiency, while not related with plant N resorption efficiency, leaf P concentrations in autumn and winter, plant P resorption proficiency. Therefore, we deduced that N was more important limiting factor to plant growth than P, and plants were stronger adaption ability to P than to N.In conclusion, leaf structure and nutrient traits depended on plant genetic characteristics, and the plant mechanisms in ecological adaption to LMA, N and P traits would be asynchronous across their evolution history. We suggested that further basic research focused on leaf traits would provide reliable theories for plant selection, community allocation and ecological management in urban garden construction.更多还原