Wood Science, Department of Forest Products, Swedish University of Agricultural Sciences, PO Box 7008, 750 07 Uppsala, Sweden.
Planta. 2012 Oct;236(4):1275-88. doi: 10.1007/s00425-012-1686-y. Epub 2012 Jun 19.
We investigated the microdistribution of xylans in different cell types of Arabidopsis stem using immunolocalization methods with LM10 and LM11 antibodies. Xylan labeling in xylary fibers (fibers) was initially detected at the cell corner of the S(1) layer and increased gradually during fiber maturation, showing correlation between xylan labeling and general secondary cell wall formation processes in fibers. Metaxylem vessels (vessels) showed earlier development of secondary cell walls than fibers, but revealed almost identical labeling patterns to fibers during maturation. No difference in labeling patterns and intensity was detected in the cell wall of fibers, vessels and protoxylem vessels (proto-vessels) between LM10 and LM11, indicating that vascular bundle cells may be chemically composed of a highly homogeneous xylan type. Interestingly, interfascicular fibers (If-fibers) showed different labeling patterns between the two antibodies and also between different developmental stages. LM10 showed no labeling in primary cell walls and intercellular layers of If-fibers at the S(1) formation stage, but some labeling was detected in middle lamella cell corner regions at the S(2) formation stage. In contrast, LM11 revealed uniform labeling across the If-fiber cell wall during all developmental stages. These results suggest that If-fibers have different xylan deposition processes and patterns from vascular bundle cells. The presence of xylan was also confirmed in parenchyma cells following pectinase treatment. Together our results indicate that there are temporal and spatial differences in xylan labeling between cell types in Arabidopsis stem. Differences in xylan labeling between Arabidopsis stem and poplar are also discussed.
我们使用 LM10 和 LM11 抗体的免疫定位方法研究了拟南芥茎不同细胞类型中木聚糖的微观分布。木聚糖在木质部纤维（纤维）中的标记最初在 S(1)层的细胞角处检测到，并在纤维成熟过程中逐渐增加，表明木聚糖标记与纤维中一般次生细胞壁形成过程之间存在相关性。木质部导管（导管）比纤维更早地发育次生细胞壁，但在成熟过程中与纤维表现出几乎相同的标记模式。在纤维、导管和原生木质部导管（原导管）的细胞壁中，LM10 和 LM11 的标记模式和强度没有差异，表明血管束细胞可能在化学组成上具有高度同质的木聚糖类型。有趣的是，束间纤维（If-纤维）在两种抗体之间以及在不同发育阶段之间表现出不同的标记模式。LM10 在 S(1)形成阶段的初生细胞壁和 If-纤维的细胞层中没有标记，但在 S(2)形成阶段的中间层细胞角区域检测到一些标记。相比之下，LM11 在所有发育阶段均在 If-纤维细胞壁上显示均匀的标记。这些结果表明，If-纤维具有与血管束细胞不同的木聚糖沉积过程和模式。在用果胶酶处理后，在薄壁细胞中也证实了木聚糖的存在。我们的研究结果表明，拟南芥茎不同细胞类型之间的木聚糖标记存在时间和空间差异。还讨论了拟南芥茎和杨树之间木聚糖标记的差异。
