本文關(guān)鍵詞：毛竹纖維細(xì)胞壁微纖絲取向與超微構(gòu)造研究　出處：《中國林業(yè)科學(xué)研究院》2016年博士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 竹纖維細(xì)胞壁 超微構(gòu)造 纖維素微纖絲 原子力顯微鏡 微纖絲角

【摘要】：竹材纖維細(xì)胞壁是植物體的力學(xué)承載單元,決定著植物體的物理、力學(xué)和化學(xué)性能,其獨特的厚薄交替多壁層結(jié)構(gòu)賦予了竹材纖維優(yōu)良的物理力學(xué)性質(zhì)。深入研究竹纖維細(xì)胞多壁層微纖絲取向與超微構(gòu)造,不僅有助于深入理解竹子的解剖構(gòu)造,而且對于竹材高附加值利用以及仿生材料設(shè)計等都具有重要的理論和現(xiàn)實意義。本文主要以毛竹(Phyllostachys edulis(Carrière)J.Houz.)第10節(jié)中部的纖維細(xì)胞為研究對象,利用偏振光顯微鏡(PLM)、場發(fā)射環(huán)境掃描電鏡(FEG-SEM)、原子力顯微鏡(AFM)對竹纖維細(xì)胞壁形貌以及纖維細(xì)胞壁各壁層微纖絲取向進(jìn)行了研究。重點利用原子力顯微鏡研究了毛竹纖維細(xì)胞各壁層微纖絲取向、細(xì)胞壁內(nèi)部精細(xì)結(jié)構(gòu)以及微纖絲超微構(gòu)造。在了解纖維細(xì)胞結(jié)構(gòu)的基礎(chǔ)上,利用同步輻射廣角X射線散射技術(shù)(SR-WAXS)從晶體角度對纖維素微纖絲的晶胞模型、結(jié)晶度、晶粒尺寸與晶型等晶體結(jié)構(gòu)進(jìn)行研究。然后利用X射線粉末衍射儀(XRD)、同步輻射廣角X射線散射(SR-WAXS)技術(shù)、小角X射線散射(SR-SAXS)技術(shù)等多種方法研究竹材微纖絲角,通過多種計算方法研究竹材的微纖絲角,從多角度探索竹材纖維細(xì)胞壁的多壁層微纖絲取向與超微構(gòu)造。得出以下的主要結(jié)論:(1)利用PLM、FEG-SEM、AFM對纖維細(xì)胞微纖絲取向方法比較得知:利用PLM可以初步判斷次生壁微纖絲角,纖維細(xì)胞厚層的微纖絲角較小,近乎與細(xì)胞軸平行,而薄層的微纖絲角較大,與細(xì)胞軸近乎垂直。利用PLM更易觀察壁層數(shù)量,具有2~3個厚層纖維細(xì)胞在纖維鞘中的占比為66%。利用FEG-SEM觀察脫木素處理后的縱切片,可以清晰的觀察到局部壁層的微纖絲角。利用AFM不僅觀察到部分壁層的微纖絲角,還可測量初生壁、胞間層、薄層等厚度。綜合以上3種設(shè)備的測試結(jié)果,AFM研究微纖絲取向是一種較優(yōu)的技術(shù)手段。(2)利用AFM觀察脫木素弦切片,纖維細(xì)胞次生壁的微纖絲角有90°、60°、30°、10°等分布。利用AFM對竹纖維細(xì)胞壁斜切面進(jìn)行連續(xù)觀察,通過三維重構(gòu)的方式無法獲得完整纖維細(xì)胞壁的結(jié)構(gòu),但可以對壁層內(nèi)部和微纖絲的超微構(gòu)造進(jìn)行研究。纖維細(xì)胞中有與紋孔相通橫向物質(zhì)。細(xì)胞壁壁層內(nèi)部結(jié)構(gòu)是由一層層定向排列良好的微纖絲層(細(xì)胞壁亞層)組成,其厚度為20nm,亞層之間填充著直徑約為18nm的木質(zhì)素顆粒。微纖絲可以由單個或多個原纖絲組成,絕大多數(shù)微纖絲截面是由3~4個原纖絲組成,尺寸為15~20nm。基于多種手段的研究結(jié)果和前人研究的基礎(chǔ)上,細(xì)化了具有2個生長周期層與細(xì)胞壁亞層結(jié)構(gòu)的細(xì)胞壁模型:初生壁微纖絲呈網(wǎng)狀排列,微纖絲與細(xì)胞主軸的夾角度數(shù)較大,初生壁厚度范圍在50nm~80nm之間。初生壁向內(nèi)是最外層的次生壁(O),微纖絲角為80°~90°,其厚度分布在100nm~1μm之間。一個生長周期層內(nèi),靠外側(cè)的微纖絲角較大,約為80°,向內(nèi)側(cè)的微纖絲角從70°至30°快速遞減,構(gòu)成過渡層,過渡至微纖絲角較小的厚層,厚層的微纖絲角分布范圍在5°~20°。過渡層厚度在整個纖維細(xì)胞中的厚度不同,在細(xì)胞中部的厚度較薄,在紡錘形纖維細(xì)胞兩端厚度較大,過渡層厚度范圍在100nm~400nm之間,在顯微鏡下呈現(xiàn)為薄層。細(xì)胞腔內(nèi)的微纖絲取向的排列整齊度較差,微纖絲角在30°~60°之間。(3)毛竹纖維素晶胞為單斜晶系,模型若以b軸為纖維軸,晶胞參數(shù)為:a=8.35?,b=10.38?,c=8.02?,β=84.99°。毛竹在赤道方向和子午方向均探測到竹材具有結(jié)晶性,利用峰高法的計算結(jié)晶度結(jié)果比分峰擬合法的計算值高15%~20%。毛竹纖維素晶體的長為16.15nm、寬為2.69nm。毛竹中的纖維素是由單斜晶系的纖維素Ⅰβ占據(jù)絕對主導(dǎo)地位。(4)當(dāng)竹材細(xì)胞沿主軸方向的旋轉(zhuǎn)時,使用0.6T法計算竹材微纖絲角的結(jié)果無明顯影響,這與0.6T法的計算理論相違背,因此,0.6T法計算毛竹平均微纖絲角存在一定局限性。通過XRD和SR-WAXS對毛竹試樣(002)和(040)晶面衍射峰的比較,利用SR-WAXS測試得到的曲線光滑程度明顯較好,使用(002)晶面計算平均微纖絲角的結(jié)果分別為9.19°和7.91°,通過XRD對試樣(040)晶面衍射峰積分法計算得到的平均微纖絲角為11.02°,通過SR-WAXS的測試結(jié)果竹材微纖絲角為6.37°,若不扣除基底,利用(040)晶面計算得到毛竹微纖絲角為11.35°,以上結(jié)果均顯示毛竹具有較小的微纖絲角。通過SR-SAXS研究結(jié)果表明毛竹的微纖絲主要以軸向分布為主,結(jié)合毛竹的解剖特征,纖維細(xì)胞的微纖絲角為0°~15°,薄壁細(xì)胞的微纖絲角約為60°。
[Abstract]:Bamboo fiber cell wall is the mechanical bearing unit of plant. It determines the physical, mechanical and chemical properties of plants. Its unique thickness and alternate multi walled structure endows bamboo fiber with excellent physical and mechanical properties. Further studies on the orientation and ultrastructure of bamboo fiber cell multi wall microfibrils not only help to understand the anatomical structure of bamboo deeply, but also have important theoretical and practical significance for the high value added utilization of bamboo and bionic material design. This paper mainly from bamboo (Phyllostachys edulis (Carri re) J.Houz.) tenth middle cells as the research object, using polarized light microscopy (PLM), field emission scanning electron microscope (FEG-SEM), atomic force microscopy (AFM) on the cell wall of bamboo fiber morphology and fiber cell wall layer of the wall of microfibril orientation to study. The microfibril orientation, the fine structure inside the cell wall and the ultrastructure of the microfibril were studied by atomic force microscopy. On the basis of understanding the structure of fibroblasts, synchrotron radiation, wide angle X ray scattering (SR-WAXS) technology was used to study the crystal cell structure, crystallinity, grain size and crystal structure of cellulose microfibrils from the point of view of crystal. Then using X - ray diffraction (XRD), wide-angle X-ray scattering of synchrotron radiation X (SR-WAXS), small angle X ray scattering (SR-SAXS) technique and other methods to study the bamboo microfibril angle, through a variety of calculation methods of microfibril angle of bamboo, explore the wall layers of cell wall of bamboo wood microfibril orientation with the micro structure from multiple perspectives. Draw the following conclusions: (1) compared with that by PLM, FEG-SEM, AFM on fibroblast microfibril orientation method: PLM could estimate the secondary wall of microfibril angle, microfibril angle of small fiber cell thick, almost parallel with the cell axis, and microfibril angle is large and thin, near the cell axis vertical. The number of wall layers was more easily observed with PLM, and the proportion of 2~3 thick layer fibroblasts in the fiber sheath was 66%. The longitudinal section of the delignification was observed by FEG-SEM, and the microfibril angle of the local wall could be clearly observed. AFM is used not only to observe the microfibril angle of the partial wall, but also to measure the thickness of the primary wall, intercellular layer and thin layer. According to the test results of the above 3 kinds of equipment, the AFM study of microfibril orientation is a better technical means. (2) using AFM to observe the delignification section, the microfibril angles of the secondary wall of the fibroblasts were 90, 60, 30 and 10 degrees. Using AFM to observe continuously the oblique section of bamboo fiber cell wall, we can not get the structure of the whole fiber cell wall by three-dimensional reconstruction, but we can study the ultrastructure of the inner wall and microfibril of the bamboo wall. In the fibroblast, there is a transverse material that is connected with the striate hole. The inner structure of cell wall layer is composed of a well arranged microfibril layer (cell wall sub layer). Its thickness is 20nm, and its sub layer is filled with lignin particles with diameter of 18NM. The microfibrils can be composed of single or multiple fibrils. Most of the microfibrils are made up of 3~4 fibrils with a size of 15~20nm. Based on the research results of previous studies and various methods on the refinement of the model with 2 layers of cell wall growth cycle and cell wall layer structure: the microfibrils in reticular arrangement, and spindle cell microfibril angle number of degree is large, the primary wall thickness in the range of 50nm~ 80nm. The primary wall is inward in the outer layer of the secondary wall (O), and the microfibril angle is 80 ~90 degrees, and its thickness is distributed between 100nm~1 and M. In a growth cycle, the lateral microfibril angle is larger than about 80 degrees, and the microfibril angle decreases rapidly from 70 to 30 degrees. It forms a transition layer, and transfers to a thicker microfibril angle. The thickness of microfibril angle ranges from 5 to ~20 degrees. The thickness of the transition layer is different in the whole fiber cell, the thickness in the middle part of the cell is thinner, the thickness at the ends of spindle fiber cells is larger, the thickness of the transition layer is between 100nm~400nm, and it appears as thin layer under microscope. The alignment of microfibril orientation in the cell cavity was poor, and the microfibril angle was between 30 degrees ~60 degrees. (3) the cell of bamboo cellulose is monoclinic, and the model is b axis, and the parameters of cell are a=8.35?, b=10.38?, c=8.02?, beta =84.99. Bamboo has crystallinity in the equatorial direction and meridional direction. The calculated value of the calculated crystallinity of the peak height method is 15%~20% higher than that of the peak fitting method. The cellulose crystal of Phyllostachys pubescens is 16.15nm in length and 2.69nm in width. The cellulose in Phyllostachys pubescens is dominated by the cellulose I beta of the monoclinic system. (4) when bamboo cells rotate along the main axis, the results of bamboo fiber microfibril angle calculated by 0.6T method have no obvious effect, which is contrary to the calculation theory of 0.6T method. Therefore, the 0.6T method has limitations in calculating the average microfibril angle of bamboo. Through XRD and SR-WAXS on bamboo samples (002) and (040) comparison of diffraction peaks, using SR-WAXS test smooth curve was significantly better, the use of (002) crystal surface to calculate the average microfibril angle results were 9.19 degrees and 7.91 degrees, the XRD of the sample (040) the average microfibril calculation get the diffraction peak integral angle is 11.02 degrees. Through the test results of SR-WAXS bamboo microfibril angle is 6.37 degrees, if not less substrate, using (040) crystal plane calculated bamboo microfibril angle is 11.35 degrees, the above results show that bamboo has smaller microfibril angle. The results of SR-SAXS showed that the microfibrils of bamboo were mainly axial distribution. Combined with the anatomical characteristics of Phyllostachys edulis, the microfibril angle of fibroblasts was 0 degree ~15 degrees, and the microfibril angle of parenchyma cells was about 60 degrees.
【學(xué)位授予單位】：中國林業(yè)科學(xué)研究院
【學(xué)位級別】：博士
【學(xué)位授予年份】：2016
【分類號】：S795.7
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本文編號：1339256