Bryant Nathan, Engle Nancy, Tschaplinski Timothy, Pu Yunqiao, Ragauskas Arthur J
Department of Chemical and Biomolecular Engineering, University of Tennessee Knoxville Tennessee 37996 USA.
BioEnergy Science Center & Center for Bioenergy Innovation, Biosciences Division, University of Tennessee-Oak Ridge National Laboratory Joint Institute for Biological Science, Oak Ridge National Laboratory Oak Ridge TN 37831 USA.
RSC Adv. 2023 Jul 5;13(29):20187-20197. doi: 10.1039/d3ra03142j. eCollection 2023 Jun 29.
Lignin has long been a trait of interest, especially in bioenergy feedstocks such as . While the stem lignin of is well studied, foliar lignin has received significantly less consideration. To this end, leaves from 11 field grown, natural variant genotypes were investigated by NMR, FTIR, and GC-MS. Five of these genotypes were sufficiently irrigated, and the other six genotypes were irrigated at a reduced rate (59% of the potential evapotranspiration for the site) to induce drought treatment. Analysis by HSQC NMR revealed highly variable lignin structure among the samples, especially for the syringyl/guaiacyl (S/G) ratio, which ranged from 0.52-11.9. Appreciable levels of a condensed syringyl lignin structure were observed in most samples. The same genotype subjected to different treatments exhibited similar levels of condensed syringyl lignin, suggesting this was not a response to stress. A cross peak of / 74.6/5.03, consistent with the form of the β-O-4 linkage, was observed in genotypes where significant syringyl units were present. Principle component analysis revealed that FTIR absorbances associated with syringyl units (830 cm, 1317 cm) greatly contributed to variability between samples. Additionally, the ratio of 830/1230 cm peak intensities were reasonably correlated (-value < 0.05) with the S/G ratio determined by NMR. Analysis by GC-MS revealed significant variability of secondary metabolites such as tremuloidin, trichocarpin, and salicortin. Additionally, salicin derivatives were found to be well correlated with NMR results, which has been previously hypothesized. These results highlight previously unexplored nuance and variability associated with foliage tissue of poplar.
长期以来，木质素一直是人们感兴趣的特性，尤其是在生物能源原料等方面。虽然[植物名称]茎中的木质素已得到充分研究，但叶片木质素受到的关注要少得多。为此，通过核磁共振（NMR）、傅里叶变换红外光谱（FTIR）和气相色谱 - 质谱联用（GC - MS）对11种田间种植的天然变异[植物名称]基因型的叶片进行了研究。其中5种基因型得到充分灌溉，另外6种基因型以较低速率（该地点潜在蒸散量的59%）灌溉以进行干旱处理。通过异核单量子相干（HSQC）核磁共振分析发现，样品间木质素结构差异很大，尤其是丁香基/愈创木基（S/G）比，范围在0.52 - 11.9之间。在大多数样品中都观察到了可观水平的缩合丁香基木质素结构。同一基因型在不同处理下表现出相似水平的缩合丁香基木质素，这表明这不是对胁迫的反应。在存在大量丁香基单元的基因型中，观察到与β - O - 4键的[具体形式]一致的/ 74.6/5.03交叉峰。主成分分析表明，与丁香基单元相关的傅里叶变换红外光谱吸光度（830 cm，1317 cm）对样品间的变异性有很大贡献。此外，830/1230 cm峰强度比与核磁共振测定的S/G比具有合理的相关性（相关系数值<0.05）。通过气相色谱 - 质谱联用分析发现，次生代谢产物如震颤素、毛果杨素和水杨苷有显著变异性。此外，水杨苷衍生物与核磁共振结果有很好的相关性，这与之前的假设一致。这些结果突出了杨树叶片组织中以前未被探索的细微差别和变异性。
