Microstructure and fiber size of the castor-oil plant

Key words: 
• material science /
• castor-oil plant /
• microstructure /
• cell type /
• fiber size

Abstract: To better use the castor-oil plant as a high quality fiber-material，the microstructure and fiber size of the cortex，xylem，and marrow of the castor-oil plant was studied with a Scanning Electron Microscope （SEM），Optics Microscope，and Motic Images Plus 2.0 image processing software system. Results showed the presence of fibers，axis-thin-wall，and radial cells in the cortex of the plant. The xylem microstructure was similar to diffuse-porous wood with the pipe orifice developed close up marrow and having linear-heterotype and non-linear-heterotype rays. Border pits were found on the fiber cell which curved in a plant burl. There also were polyhedral-shin wall cells and spiral vessels in the plant marrow. The cortex fiber cell was most to 26.50 mm in length，high to 540.00 in ratio of length to width and had a cell wall：cell cavity in width of 0.56∶0.83. The fiber cell of the plant’s branch-cortex was longest in length and largest in length to width ratio. The plant’s fiber cell of spike-cortex was shortest in length，smallest in length to width ratio and wall to cavity in width. The xylem fiber cell was from 0.75 to 0.90 mm in length，from 4.38 to 5.40 μm in width，and had a length to width cell ratio of 31.78∶37.54. The cell wall∶cell cavity in width was from 0.56 to 0.83. For the axes，the average length and width of the cell cavity and the length：width of the branch fiber cell was smaller than those of the trunk fiber cell，but the cell wall to cell cavity ratio for the width of the branch fiber cell was greater than or equal to those of the trunk fiber cell. In the spike the length，cell width，and cell cavity width of the fiber cell was smallest，but the cell length∶width and the width of the cell wall ∶ cell cavity was largest. In middle part of the xylem the radial length，cell cavity width，and the length∶width ratio of the fiber cell was larger，and the cell width，cell wall width，and cell wall ∶ cell cavity in width of the fiber cell in outside were largest. Thus，the fiber size was different in the different parts of the castor-oil plant. Since this fiber is an excellent material，it can be used to make paper or make artificial boards. ［Ch，9 fig. 3 tab. 10 ref.］