蔺草底部茎秆解剖构造与力学性能

Anatomical structure and mechanical properties from stem bottoms of Juncus effusus

蔺草Juncuse effisus茎秆是一种优质天然纤维.研究蔺草茎秆解剖构造与力学性能,为全面了解蔺草及其纤维的开发利用提供理论依据.以5份蔺草种质为研究对象,观测其解剖构造,运用电子万能力学试验机测试其力学性能,并分析解剖构造与力学性能之间的关系.结果表明：蔺草底部茎秆微观结构分为表皮、基本组织、维管束和髓;蔺草纤维呈纺锤形,长度为681.47-712.04μm,宽度为5.58-8.00μm,壁腔比范围为1.194-1.556;5份蔺草种质底部茎秆的最大拉力范围为61.59-72.71N,XY004的最大拉力最高,拉伸强度为33.28-59.11MPa,XY003的拉伸强度最大,拉伸弹性模量为1438.23-2297.10MPa;蔺草底部茎秆拉伸强度、拉伸弹性模量与其维管束总数目呈极显著正相关,相关系数分别为0.818和0.724,与茎壁厚/茎半径也呈极显著正相关,相关系数分别为0.740和0.748,与纤维的壁腔比呈显著正相关,相关系数分别为0.584和0.663,与粗纤维质量分数无显著相关性;蔺草底部茎秆力学性能主要取决于茎秆维管束总数目、基本组织厚度和纤维的壁腔比以及各组织及其各细胞之间的连接形式和连接强度.供试的5份蔺草种质中,XY003和XY004底部茎秆具有较高的强度和良好的弹性,可作为优良蔺草品种选育的种质资源。

To provide guidance for genetic breeding and better utilization of Juncus effusus, a high-quality nat-ural fiber material with strength and flexibility, the anatomical structure from stems of five cultivars （XY001, XY002, XY003, XY004, and XY007） was observed under a microscope. Then mechanical properties of rush stems in maturity were measured by an electronic testing machine （CTM 6000）, and relationships between anatomical structure and mechanical properties were analyzed with a correlation analysis. Results showed that the microstructure was composed of epidermis, elementary tissue, vascular bundles, and pith. The cell length was 681.47-712.04 !m, the width was 5.58-8.00 !m, and the ratio of the cell wall to the cavity of the fiber was 1.194-1.556. Also, the maximum tensile force was 61.59-72.71 N, the tensile strength was 33.28-59.11 MPa, and Young’s modulus of the rush stems was 1 438.23-2 297.10 MPa. The best of the maximum tensile force was cultivar XY004, but XY003 had the best tensile strength and Young’s modulus. The correlation analysis showed a highly significant and positive relationship of tensile strength to the total number of vascular bundles （8 〈 0.01, r = 0.818） and the ratio of wall thickness to radius of stems （9 〈 0.01, r = 0.740）. Also,Young＇s modulus was highly significant and positive correlated with the total number of vascular bundles （P 〈 0.01, r = 0.724） and the ratio of wall thickness to radius of stems （P 〈 0.01, r = 0.748）. A significant positive correlation was also found for tensile strength （P 〈 0.05, r = 0.584） and Young＇s modulus （ P 〈 0.05, r = 0.663） compared to the ratio of the cell wall to the cavity of the fiber. The mechanical properties from stem bottoms of Juncus ejfusus depended on the numbers of vascular bundles, the elementary tissue thickness, the ratio of the cell wall to the cavity of the fiber and the connecting form and strength of each organization. The findings suggested that compared with the other three cultivars, XY003 and XY004 had higher strength and flexibility making them better candidates for genetic breeding. [Ch, 4 fig. 4 tab. 33 ref. ]