摘要
应用原子力显微镜观察了女贞(Ligustrum lucidum)、珊瑚树(Viburnum odoratissimum)幼叶和成熟叶的表面特征,并探讨了叶面微结构对滞尘能力的可能影响以及抵抗干旱、污染物等胁迫的能力。女贞幼叶和成熟叶正背面的粗糙度Ra分别为417.8、794.5、1069、957.4 nm;珊瑚树幼叶和成熟叶正背面的粗糙度Ra分别为471.3、469.6、291.1、865.9 nm。和幼叶相比,成熟叶表面的粗糙度发生变化,但2个物种的变化趋势不同,这种变化可能与气孔的发育以及外界环境条件对叶片表面形态结构、蜡质含量和成分的影响不同有关。叶片表面存在大量的沟状、孔状峰谷区域和直径约为10μm的凹陷,有利于PM10的滞留。女贞和珊瑚树成熟叶气孔只分布在叶下表皮且下陷。这些特征均说明女贞和珊瑚树具有较强的滞尘能力和抵抗干旱、污染物胁迫的能力,作为绿篱植物对消减城市大气颗粒物污染和提高空气质量具有重要的意义。
Leaf surfaces are multifunctional interfaces between plant and their environment which affect both ecological and biological processes.Leaf surface topography is an important characteristic that directly affects microhabitat and microclimate availability for dust deposition,water storage and microbial colonization.However,few studies have been conducted which measure accurately the three dimensional structure of the leaf surface or record precise changes of leaf surface microstructure over time.The Atomic Force Microscopy（AFM） is one of the most powerful tools for determining the surface topography of native biomolecules at subnanometer resolution,and can image a wide variety of samples under variable conditions,thus providing a new way to probe biological structures.Using oscillating mode AFM,we measured the two- and three-dimensional coordinates of adaxial and abaxial surfaces of Ligustrum lucidum and Viburnum odoratissimum,two common perennial plant species for urban greening in Xi′an City,on leaves of two age classes.We then produced topographic maps of these leaf surfaces,which revealed striking differences between adaxial and abaxial surfaces and between age classes.The leaf surface was uneven due to wax crystals,stomata,various cells,papillae and hollows.For Ligustrum lucidum,the roughness of adaxial and abxaxial surface was 417.8 nm and 794.5 nm for young leaves,1069 nm and 957.4 nm for old leaves,respectively.Old leaves had much rougher surfaces than young leaves.However,in Viburnum odoratissimum,the roughness of adaxial and abaxial surface for young leaves was 471.3 nm and 469.6 nm respectively,and 291.1nm and 865.9 nm for old leaves.The adaxial surface of young leaves was rougher than old leaves,but the abaxial surface was the converse.The roughness of plant leaves was much greater than artificial surfaces with only several nanometer elevation.The different change of leaf surface roughness in the two plants may be related to the development of stomata,the changes of amount,chemical composition,and crystal structure of cuticular wax.There existed many papillae and hollows on the adaxial surface of these two plants with a radius of about 10 μm;a structure able to capture PM10（particle matter with aerodynamic diameter less than 10 μm）,which was now thought to be the most important of the commonly occurring air pollutants.The shape of the epidermal cells of the old leaves in these two plants was irregular,and the stomatal apparatus only distributed on the abaxial surface and sunk into epidermis.It can be inferred that the two species examined in this study showed high dust capturing capacity and stress tolerance of drought and environmental pollutants,and can be recommended for introduction as avenue trees along road sides or as road dividers.Our results also indicated that AFM was an effective method for quantifying and comparing leaf surface landscape patterns and identifying the critical features at a scale relevant to both biological and physical processes on the leaf surfaces.
出处
《生态学报》
CAS
CSCD
北大核心
2011年第5期1471-1477,共7页
Acta Ecologica Sinica
基金
国家自然科学基金项目(31070541)
陕西省环境科学重点学科建设项目资助
关键词
原子力显微镜
叶表面微结构
粗糙度
滞尘
atomic force microscopy（AFM）
leaf surface morphology
roughness
dust capturing
