Kokubo A, Kuraishi S, Sakurai N
Department of Environmental Studies, Faculty of Integrated Arts and Sciences, Hiroshima University, Naka-ku, Hiroshima 730, Japan.
Plant Physiol. 1989 Nov;91(3):876-82. doi: 10.1104/pp.91.3.876.
Grass culms are known to differ in breaking strength, but there is little physicochemical data to explain the response. The fourth internode of four brittle and two nonbrittle barley (Hordeum vulgare L.) strains were used for physical and chemical studies of culm strength. Inner and outer culm diameters of brittle strains (3.6 +/- 0.2 and 5.0 +/- 0.1 millimeters) were not significantly different from those of nonbrittle strains (3.9 +/- 0.2 and 5.2 +/- 0.2 millimeters). Maximum bending stress, at which the culm was broken, was 192 +/- 34 g/mm(2) for brittle and 490 +/- 38 g/mm(2) for nonbrittle strains. Wall thickness and cell dimensions of epidermal, sclerenchyma, and parenchyma cells were measured in culm cross sections. The area of cell wall per unit cell area for each tissue was significantly correlated with the maximum bending stress (r = 0.93 for epidermis, 0.90 for sclerenchyma, and 0.84 for parenchyma). Cell walls of brittle culms had 6 to 64% as much cellulose content as those of nonbrittle culms. Maximum bending stress correlated significantly with cellulose content of the cell walls (r = 0.93), but not with the contents of noncellulosic compounds. The lower cellulose content of the brittle culm was significantly correlated with brittleness.
已知禾本科植物的茎秆在抗折断强度方面存在差异，但几乎没有物理化学数据来解释这种差异。本研究选用了4个脆秆大麦和2个非脆秆大麦（Hordeum vulgare L.）品系的第四节间进行茎秆强度的物理和化学研究。脆秆品系的茎秆内径和外径（3.6±0.2毫米和5.0±0.1毫米）与非脆秆品系（3.9±0.2毫米和5.2±0.2毫米）无显著差异。脆秆品系茎秆折断时的最大弯曲应力为192±34克/平方毫米，非脆秆品系为490±38克/平方毫米。对茎秆横切面的表皮细胞、厚壁细胞和薄壁细胞的壁厚及细胞尺寸进行了测量。各组织单位细胞面积的细胞壁面积与最大弯曲应力显著相关（表皮细胞r = 0.93，厚壁细胞r = 0.90，薄壁细胞r = 0.84）。脆秆茎秆细胞壁的纤维素含量是非脆秆茎秆的6%至64%。最大弯曲应力与细胞壁纤维素含量显著相关（r = 0.93），但与非纤维素化合物含量无关。脆秆茎秆较低的纤维素含量与脆性显著相关。
