Structural Insight into Cell Wall Architecture ofMicanthus sinensiscv. using Correlative Microscopy Approaches

Abstract

Structural organization of the plant cell wall is a key parameter for understanding anisotropic plant growth and mechanical behavior. Four imaging platforms were used to investigate the cell wall architecture of Miscanthus sinensis cv. internode tissue. Using transmission electron microscopy with potassium permanganate, we found a great degree of inhomogeneity in the layering structure (4-9 layers) of the sclerenchymatic fiber (Sf). However, the xylem vessel showed a single layer. Atomic force microscopy images revealed that the cellulose microfibrils (Mfs) deposited in the primary wall of the protoxylem vessel (Pxv) were disordered, while the secondary wall was composed of Mfs oriented in parallel in the cross and longitudinal section. Furthermore, Raman spectroscopy images indicated no variation in the Mf orientation of Pxv and the Mfs in Pxv were oriented more perpendicular to the cell axis than that of Sfs. Based on the integrated results, we have proposed an architectural model of Pxv composed of two layers: an outermost primary wall composed of a meshwork of Mfs and inner secondary wall containing parallel Mfs. This proposed model will support future ultrastructural analysis of plant cell walls in heterogeneous tissues, an area of increasing scientific interest particularly for liquid biofuel processing.

Super-Resolution Imaging of Xylem Cell Wall Nanostructure Using SRRF Microscopy

“…Some of the concentric lamellae observed with SRRF analysis of rhodamine B staining were associated with the boundaries between ligni cation levels within the S2 layer. Similar variations in ligni cation within the secondary cell wall have been reported in bamboo bres by TEM [2,[11][12][13][14][15]. However, concentric lamellae in Douglas r latewood cell walls are indistinct by conventional light microscopy and have not previously been described.…”

“…Bamboo parenchyma, phloem, and xylem bres have polylamellate cell walls with multiple layers associated with changes in micro bril orientation, ligni cation, and amount of xylan [2,[11][12][13][14][15].…”

How did correlative atomic force microscopy and super-resolution microscopy evolve in the quest for unravelling enigmas in biology?

“…39,40 The possibility of retrieving physical, chemical and biological information in complex systems using correlative microscopy methods set the stage for the emergence of hybrid systems. 41,42 Over the past two decades AFM has been combined with electron microscopy, 43,44 confocal Raman microspectroscopy 45 and optical [46][47][48] and fluorescence microscopy techniques. Fluorescence microscopy is a popular imaging technique † Contributed equally.…”

Super-resolution imaging of Douglas fir xylem cell wall nanostructure using SRRF microscopy

“…Some plant cell walls are known to contain concentric lamellae at different scales [ 14 , 16 , 17 ]. Observations by TEM often show lamellae consisting of individual cellulose microfibrils and matrix materials on a scale of about 3 nm [ 1 , 18 ].…”