Seasonal and clonal variation in cellulose microfibril orientation during cell wall formation of tracheids in Cryptomeria japonica
Seasonal and clonal variation in cellulose microfibril orientation during cell wall formation of tracheids in Cryptomeria japonica
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日本柳杉管胞细胞壁形成过程中纤维素微纤丝方向的季节和克隆变化
DOI：
10.1093/treephys/tpu008
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发表时间：
2014
期刊：
影响因子：
4
通讯作者：
Hisashi Abe
中科院分区：
文献类型：
--
作者：
Tuula Jyske;Takeshi Fujiwara;Katsushi Kuroda;Taiichi Iki;Chunhua Zhang;Tuomas K. Jyske;Hisashi Abe
为探讨树木控制针叶树管胞次生细胞壁微纤丝（MF）取向变化的生物学机制，研究了柳杉（Cryptomeria japonicaD.）日本中部（36°36′N，140°39′E）。在2010年的生长季节，从4个16岁的不同来源的克隆重复收集样品块，以调查壁层之间的纤维素MF取向的变化表现出季节性和克隆差异的假设。用场发射扫描电子显微镜观察到管胞初生和次生细胞壁层上新沉积的微纤维取向的渐进变化。光学显微镜观察管胞的产生和分化。在S2和S1层中，从早材到晚材，沉积的MFs的取向呈下降趋势，其中MFs以Z-螺旋的形式出现。与此相反，没有季节性的模式中的方向的MF的S-螺旋观察。在管胞产生和分化的物候学上观察到较小的克隆变异。我们的结论是，在S1和S2的Z-螺旋的方向的MF的季节性下降的趋势，而在其他层的MF表现出轻微的随机变化。因此，S2层中MF的取向受到季节因素的影响，而其他层中MF的取向则更多地受到内在控制。环内的MF方向的变化，从而产生的平均MF角也可能与管胞生产和分化率的基因型差异。然而，我们的研究结果并不排除其他内在的和环境的规定，在MF取向的变化，这仍然是一个主题，为未来的研究。
To investigate the biological mechanism by which trees control the changes in microfibril (MF) orientation among secondary cell wall layers of conifer tracheids, we studied seasonal variation in the orientation of newly deposited MFs during tracheid cell wall development in Japanese cedar (Cryptomeria japonicaD. Don) trees growing in Central Japan (36°36′N, 140°39′E). Sample blocks were repeatedly collected from four 16-year-old clones of different origins during the growing season of 2010 to investigate the hypotheses that changes in cellulose MF orientation between wall layers exhibited seasonal and clonal differences. The progressive change in the orientation of newly deposited MFs on the primary and secondary cell wall layers of tracheids was detected by field-emission-scanning electron microscopy. Tracheid production and differentiation was studied by light microscopy. We observed a decreasing trend in the orientation of deposited MFs from earlywood to latewood in the S2and S1layers, where MFs appeared in a Z-helix. In contrast, no seasonal pattern in the orientation of the MFs in the S-helix was observed. Minor clonal variation was observed in the phenology of tracheid production and differentiation. We concluded that a seasonal decreasing trend in the orientation of the MFs in the Z-helix in S1and S2was present, whereas the MFs in other layers exhibited minor random variations. Thus, the orientation of the MFs in S2was affected by seasonal factors, whereas the MFs in other layers were more intrinsically controlled. The within-ring variations in the MF orientation and thus the resulting average MF angle might also be related to genotypic differences in the tracheid production and differentiation rate. However, our results do not exclude other intrinsic and environmental regulations in the change in MF orientation, which remains a topic for future studies.