Intrusive growth of flax phloem fibers is of intercalary type
Intrusive growth of flax phloem fibers is of intercalary type
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DOI：
10.1007/s00425-005-1536-2
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发表时间：
2005-11-01
期刊：
影响因子：
4.3
通讯作者：
van Lammeren, AAM
中科院分区：
文献类型：
--
作者：
Ageeva, MV;Petrovská, B;van Lammeren, AAM
亚麻（Linum usitatissimum L.）韧皮部纤维在其发育过程中显著伸长并侵入现有细胞之间。我们质疑纤维伸长是由细胞尖端生长还是由中间生长引起的。具有尖端生长的细胞的特征在于在细胞尖端中具有两个特定的细胞质区域，一个具有囊泡，并且在非常尖端处没有大的细胞器，另一个具有各种细胞器，其中包括在亚尖端中纵向排列的皮质微管。在拉伸亚麻纤维时没有观察到这种区域。相反，细胞器移动到最顶端的区域，和皮质微管显示横向和螺旋状的配置，如已知的细胞生长在中间的方式。此外，使用Calcofluor白色的脉冲追逐实验导致整个纤维长度上的细胞壁中出现点状荧光。因此，得出纤维伸长不是通过尖端生长而是通过插层生长实现的结论。侵入生长的纤维是一个没有胞间连丝的多核细胞，使纤维在茎内成为一个共质体孤立的区域。
Flax (Linum usitatissimum L.) phloem fibers elongate considerably during their development and intrude between existing cells. We questioned whether fiber elongation is caused by cell tip growth or intercalary growth. Cells with tip growth are characterized by having two specific zones of cytoplasm in the cell tip, one with vesicles and no large organelles at the very tip and one with various organelles amongst others longitudinally arranged cortical microtubules in the subapex. Such zones were not observed in elongating flax fibers. Instead, organelles moved into the very tip region, and cortical microtubules showed transversal and helical configurations as known for cells growing in intercalary way. In addition, pulse-chase experiments with Calcofluor White resulted in a spotted fluorescence in the cell wall all over the length of the fiber. Therefore, it is concluded that fiber elongation is not achieved by tip growth but by intercalary growth. The intrusively growing fiber is a coenocytic cell that has no plasmodesmata, making the fibers a symplastically isolated domain within the stem.