Nuclei of Taxus baccata: Flavanols Linked to Chromatin Remodeling Factors
Nuclear flavanol patterns as evidenced by blue colouration with the selective DMACA reagent. (*Size of the nuclei in m diameter). Elongating shoot tips (a)–(d). (a) Dark blue interphase cell (nucleus*8 m in diameter). Pale blue nucleus with a large nucleolus (<) and pale chromosome staining during metaphase. (b) Mature cell from the phloem region showing a large kidney-like vacuole filled with flavanols. The halfway enclosed nucleus (*7 m in diameter) stains only a moderate blue. Two nearby located nuclei of vacuole-free cells (nucleus*11 m in diameter) stained a comparatively darker blue (see right side of (b)). (c) Two multi-vacuolate cells having achieved large quantities of stored flavanols. The nuclei are compacted (*6 m in diameter), and stain a very deep blue colour together with fine granules of condensed chromatin. Two adjacent cells without vacuoles possess enlarged and moderate blue nuclei (*about 12 to 13 m in length). Condensed chromatin spots are fine structured. The size of the nuclei points to a prophase stage. (d) Two adjacent lineages exhibit a slightly unequal size and show a different nuclear flavanol pattern (nucleus* 8 m in diameter). Upper lineage: pale blue nuclei with finer grained chromatin spots. Lower lineage: moderate blue nuclei with coarse grained chromatin spots. Elongating needles (e)–(k). (e) cells with distinct nuclear flavanol aggregation patterns. The nuclei of the lineage cells stain dark blue (*7 m in diameter) which stand out in sharp contrast against the lighter blue cytoplasm. Patches of dark blue heterochromatin indicate a special nuclear condition. The nuclei of the starch cells (s) stain pale blue. (f) Members of two cell lineages consist of four cells each, but only two cells are shown. Size, shape, and nuclear staining patterns differ markedly. The small lineage cells indicate more nuclear flavanol deposition (nucleus*7 m in diameter), compared with the large lineage cells. (g) this cell lineage is characterized by nuclei which are almost the same in size and shape. The nuclear flavanol pattern is generally smooth, lacking dense chromatin spots (nucleus*8 m in diameter). Strikingly, each nucleus has a small nucleolus. (h) two multivacuolate parenchyma cells each stores abundant flavanols. Their centrally located nuclei are less coloured than those of the adjacent five vacuole free cells (nucleus*7 m in diameter). The five single cells are derivatives from a former lineage and have started to differentiate in size, shape, and nuclear flavanol pattern. (i) elongated cell with anaphase chromosomes and two daughter cells resulting from a recent transversal division (nucleus*8 m in diameter). Distinct chromosomal and nuclear domains stain a dark blue. (j) ana-telophase chromosomes and four interphase cells with dark blue nuclei. Somewhat diffuse but marked spots of heterochromatin are distributed throughout the euchromatin (nucleus*10 m in length). (k) very compacted, somewhat diffuse chromatin during mid-telophase. The nucleus of the interphase cell is slightly diffuse and of a deep colour (*8 m in diameter) together with some large heterochromatin patches.
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