Kausch A P, Horner H T
Eur J Cell Biol. 1984 Jan;33(1):7-12.
Longitudinal files of raphide crystal idioblasts form within the cortical meristematic region of Vanilla planifolia aerial roots. Cell and nuclear enlargement occur gradually throughout idioblast development and nuclear diameter approximates idioblast maturity. Cytophotometric determination of nuclear DNA (Feulgen) contents, measured by the two-wavelength method, revealed that all cortical parenchyma cells are diploid (2C = 6.3 pg), whereas all crystal idioblast nuclei are endopolyploid. Idioblast nuclear DNA content ranged from 4C to 32C (106 pg) and averaged 5.9 times that of parenchyma telophase nuclei. Frequency distribution of individual DNA content measurements depicts multiple genomes (increasing with geometric periodicity) to the 8C level, followed by less strict DNA replication within the crystal idioblast genome. The largest nuclei had the highest DNA content. Endomitotic stages of preprophasic heterochromatic dispersion (Z phase) and partial prophasic chromosomal coiling are observed with light and electron microscopy. DNA content values above the 8C level do not fit the geometrical order which is found if the total genome is replicated during each endo-cycle, a result indicating differential DNA replication. Chromocenter counts substantiate the occurrence of endomitosis to the 8C level and suggest heterochromatin underreplication in higher endopolyploid idioblast nuclei. Possible relationships between observed cytological events of idioblast development and nuclear condition are discussed.
针晶异细胞的纵向列在香荚兰气生根的皮层分生组织区域内形成。在整个异细胞发育过程中，细胞和细胞核逐渐增大，细胞核直径接近异细胞成熟时的大小。通过双波长法测量的细胞核DNA（福尔根）含量的细胞光度测定显示，所有皮层薄壁细胞都是二倍体（2C = 6.3 pg），而所有晶体异细胞的细胞核都是内多倍体。异细胞细胞核DNA含量范围为4C至32C（106 pg），平均是薄壁细胞末期细胞核的5.9倍。单个DNA含量测量的频率分布描绘了到8C水平的多个基因组（以几何周期增加），随后在晶体异细胞基因组内DNA复制不太严格。最大的细胞核具有最高的DNA含量。用光镜和电镜观察到前前期异染色质分散（Z期）和部分前期染色体卷曲的核内有丝分裂阶段。高于8C水平的DNA含量值不符合如果在每个内循环期间整个基因组都被复制时所发现的几何顺序，这一结果表明存在差异DNA复制。染色中心计数证实了到8C水平的核内有丝分裂的发生，并表明在更高的内多倍体异细胞细胞核中异染色质复制不足。讨论了观察到的异细胞发育的细胞学事件与核状况之间的可能关系。
