水稻中的纳米硅及其紫外吸收  

Nanoscale Silicas in Oryza Sativa L. and Their UV Absorption

作　　者：房江育[1] 宛晓春[1] 马雪泷[2] 

机构地区：[1]安徽农业大学园艺学博士后流动站,安徽合肥230036 [2]黄山学院生物多样性研究所,安徽黄山245021

出　　处：《光谱学与光谱分析》2006年第12期2315-2318,共4页Spectroscopy and Spectral Analysis

基　　金：国家自然科学基金项目(30170185);安徽省教育厅自然科学基金项目(2005kj398zc);安徽省高等学校"十五"学科带头人培养计划项目资助

摘　　要：为了了解水稻中硅的亚显微结构及其紫外吸收特性，根据强酸不会腐蚀SiO2玻璃的事实，选择湿消化方法分离水稻中的硅体。以浓硫酸和硝酸混合液分别处理水稻叶片和稻壳，经多级沉降分离出其中的硅体。X射线光电子能谱结果表明硅体距离表面10nm以内碳相对质量为35．05％，远高于硅体表面（5．88％），说明硅质壁能够阻止强酸进入硅体内部，避免硅体内氧化，保持硅体结构完整和相对独立的理化性质。电镜显示硅体SiC）：结构致密，由1～2nm的SiO2凝胶粒子粘聚而成，纳米颗粒相互融合组成排列方向一致的纳米棒，内部还有微米尺度（≤1μm）和纳米尺度（≤1～2nm）的隙孔。颖壳硅体最大吸收位于285nm；叶片纳米硅对紫外辐射的吸收极其有限，表明水稻颖壳和叶片硅体对紫外辐射具有不同的抵抗机制。To reveal the unique microstructure of silica in rice and its absorption of ultra violet, wet digestion was chosen to isolate silica bodies from rice leaves and bract according to the fact that concentrated acid cannot destroy glass made of SiO2. A mixed solution of sulfuric and nitric acids was applied to the leaves and bract of rice, respectively. After keeping the treated sam ples in 60-70 ~C water bath for 30 hours and times of washing and sedimentation in water, pure silica bodies were obtained. The detection by X-ray photoelectron speetroscopy（XPS） indicated that there was 35. 05% of carbon 10 nm under the surface of the silica body, much more than the amount of 5.88% on the out surface which might be due to the contamination of the air contact with the sample. This fact showed that acid couldn＇t get into the silica body to oxidize the inner organic compounds to alter the structure, therefore the chemical and physical properties of the silica measured could account for the original status in the leaf and bract. Scanning electron microscopy and transmission electron microscopy observation revealed that the silica body of rice is made up of inseparable SiO3 particles of 1-2 nm, sticking slackly to form nano-scale rods of average 45 nm wide and arranging in the same direction. Besides, there were lots of pores inside the inner part of the silica body, including both micron-scale pores（≤ 1 μm） and nano interstitial pores（≤1-2 nm）. The bract silica has the greatest absorption at 285 nm of UV-B, while the leaf silica has a very low UV absorption, indicating that silica in the two organs of rice has different mechanism of radiation resistance.

关 键 词：水稻 硅体 纳米 紫外吸收 

分 类 号：Q63[生物学—生物物理学] Q944