School of Life Science, Shaoxing University, Shaoxing 312000, China; College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
Tea Research Institute of Sichuan Academy of Agricultural Science, Chengdu 610066, China.
Ecotoxicol Environ Saf. 2022 Nov;246:114178. doi: 10.1016/j.ecoenv.2022.114178. Epub 2022 Oct 13.
Plant root growth is inhibited markedly by aluminium (Al) even at micromolar concentration and Al is mainly accumulated in plant roots outer layer cell walls. But the underlying reason for this asymmetric transverse distribution is unknown. In this study, two wheat (Triticum aestivum L.) genotypes ET8 and ES8 differing in Al resistance were investigated by hydroculture. The Al-tolerant ET8 expressed a higher root elongation rate (RER) than Al-sensitive ES8 under Al stress. Morphological examination showed symptoms such as root surface ruptures were observed in ET8 and ES8, with ES8 being more obvious. The cation exchange capacity (CEC) values of root tips of ES8 under different Al concentrations are higher than those of ET8. The sensitive genotype ES8 accumulated more Al than ET8 in plant apical root tips as well as cell walls. Under 48 h Al exposure, the root cell wall pectin concentration was increased with a higher magnitude in ES8 than in ET8. The functional groups on ET8 and ES8 roots outer layer and inner cells were investigated by Fourier transform infrared spectrometry (FTIR) under Al stress. The FTIR spectra of selected examined areas showed that the characteristic absorption peaks were located at 1692, 2920, and 3380 cm. The outer layer cells had stronger peaks than inner cells at wavenumber 1680-1740 cm, indicating root outer layer cells contain more carboxyls in both ET8 and ES8. The results demonstrate that Al transverse distribution on plants apical root cross section is likely influenced by functional groups such as negatively charged carboxylic acid.
植物根系的生长会被铝（Al）显著抑制，即使在微摩尔浓度下也是如此，而且 Al 主要积累在植物根部外层细胞壁中。但是这种不对称的横向分布的根本原因尚不清楚。在这项研究中，通过水培法研究了两个小麦（Triticum aestivum L.）基因型 ET8 和 ES8，它们在耐铝性上存在差异。在 Al 胁迫下，耐铝性较强的 ET8 的根伸长率（RER）高于 Al 敏感型 ES8。形态学检查表明，ET8 和 ES8 都出现了根表面破裂等症状，而 ES8 更为明显。不同 Al 浓度下 ES8 的根尖阳离子交换量（CEC）值高于 ET8。敏感基因型 ES8 在根尖和细胞壁中积累的 Al 比 ET8 更多。在 48 h Al 暴露下，ES8 中的根细胞壁果胶浓度增加幅度高于 ET8。通过傅里叶变换红外光谱（FTIR）研究了 Al 胁迫下 ET8 和 ES8 根部外层和内层细胞的功能基团。所选检查区域的 FTIR 光谱显示，特征吸收峰位于 1692、2920 和 3380 cm 处。在波数 1680-1740 cm 处，外层细胞的峰强于内层细胞，这表明 ET8 和 ES8 的外层细胞含有更多的羧基。结果表明，植物根尖横截面中 Al 的横向分布可能受到带负电荷的羧酸等功能基团的影响。
