Department of Cytophysiology, University of Łódź, Pilarskiego 14, 90-321 Łódź, Poland.
Micron. 2010 Jun;41(4):283-8. doi: 10.1016/j.micron.2009.11.011. Epub 2009 Dec 4.
Internal organization of a nucleolus changes along with rRNA transcriptional activity. These changes mainly concern qualitative and quantitative alternations of three main nucleolar components: fibrillar centres (FC), dense fibrillar component (DFC) and granular component (GC). In the present work quantitative measurements of the number and sizes of FCs and DFCs in nucleoli of root meristematic cells of soybean seedlings grown at (1) chilling conditions that reduce transcriptional activity of soybean nucleoli (temp. of 10 degrees C) and at (2) conditions that increase this activity (recovery at optimal temp. of 25 degrees C after previous chilling), even more than (3) the control, have been carried out. Morphometric measurements showed that the highest number of FCs and DFCs was in the most active nucleoli, while the smallest number - in those with the lowest activity. The average size of an individual FC was similar in all nucleoli regardless of their transcriptional activity, that of the individual DFC varied, being bigger in the nucleoli of the chilled plants and smallest in those of the recovered plants. The numbers of FCs and DFCs seem to be indicators of transcriptional activity of plant nucleoli - the higher number of FCs and DFCs the more active nucleoli.
核仁的内部组织随着 rRNA 转录活性的变化而变化。这些变化主要涉及三种主要核仁成分的定性和定量变化：纤维中心（FC）、致密纤维成分（DFC）和颗粒成分（GC）。在本工作中，对在以下条件下生长的大豆幼苗根分生细胞核仁中 FC 和 DFC 的数量和大小进行了定量测量：（1）在降低大豆核仁转录活性的冷胁迫条件下（温度为 10°C）；（2）在先前冷胁迫后恢复到最佳温度 25°C 时，增加转录活性的条件下；（3）作为对照。形态计量学测量表明，在最活跃的核仁中，FC 和 DFC 的数量最多，而在活性最低的核仁中，FC 和 DFC 的数量最少。无论转录活性如何，单个 FC 的平均大小在所有核仁中都相似，而单个 DFC 的大小则不同，在冷胁迫植物的核仁中较大，在恢复植物的核仁中最小。FC 和 DFC 的数量似乎是植物核仁转录活性的指标——FC 和 DFC 的数量越多，核仁越活跃。
