Institute of Cytology and Genetics, Siberian Branch of Russian Academy of Sciences, Novosibirsk, 630090, Russia.
Institute of Postharvest and Food Sciences, Agricultural Research Organization (ARO)-Volcani Institute, Rishon LeZion, 7505101, Israel.
Ann Bot. 2023 Dec 5;132(6):1159-1174. doi: 10.1093/aob/mcad107.
During the analysis of plant male meiocytes coming from destroyed meiocyte columns (united multicellular structures formed by male meiocytes in each anther locule), a considerable amount of information becomes unavailable. Therefore, in this study intact meiocyte columns were studied by volume microscopy in wild-type rye for the most relevant presentation of 3-D structure of rye meiocytes throughout meiosis.
We used two types of volume light microscopy: confocal laser scanning microscopy and non-confocal bright-field scanning microscopy combined with alcohol and aldehyde fixation, as well as serial block-face scanning electron microscopy.
Unusual structures, called nuclear protuberances, were detected. At certain meiotic stages, nuclei formed protuberances that crossed the cell wall through intercellular channels and extended into the cytoplasm of neighbouring cells, while all other aspects of cell structure appeared to be normal. This phenomenon of intercellular nuclear migration (INM) was detected in most meiocytes at leptotene/zygotene. No cases of micronucleus formation or appearance of binucleated meiocytes were noticed. There were instances of direct contact between two nuclei during INM. No influence of fixation or of mechanical impact on the induction of INM was detected.
Intercellular nuclear migration in rye may be a programmed process (a normal part of rye male meiosis) or a tricky artefact that cannot be avoided in any way no matter which approach to meiocyte imaging is used. In both cases, INM seems to be an obligatory phenomenon that has previously been hidden by limitations of common microscopic techniques and by 2-D perception of plant male meiocytes. Intercellular nuclear migration cannot be ignored in any studies involving manipulations of rye anthers.
在分析来自破坏的花粉母细胞柱（由每个花药室中的雄性花粉母细胞形成的联合多细胞结构）的植物雄性花粉母细胞时，会丢失大量信息。因此，在这项研究中，通过体视学显微镜研究了野生型黑麦的完整花粉母细胞柱，以最有效地呈现整个减数分裂过程中黑麦花粉母细胞的 3-D 结构。
我们使用了两种类型的体视学显微镜：共聚焦激光扫描显微镜和非共焦明场扫描显微镜，结合酒精和醛固定，以及连续块面扫描电子显微镜。
检测到称为核突起的异常结构。在某些减数分裂阶段，核形成突起，穿过细胞壁通过细胞间通道，并延伸到相邻细胞的细胞质中，而细胞结构的所有其他方面似乎都正常。这种核间核迁移（INM）现象在大多数花粉母细胞的细线期/合线期都有检测到。没有发现微核形成或双核花粉母细胞出现的情况。在 INM 过程中，两个核之间存在直接接触。没有发现固定或机械冲击对 INM 诱导的影响。
黑麦中的核间核迁移可能是一个程序化的过程（黑麦雄性减数分裂的正常部分），或者是一种无法避免的棘手假象，无论采用哪种花粉母细胞成像方法都无法避免。在这两种情况下，INM 似乎都是一种强制性现象，以前由于普通显微镜技术的限制和对植物雄性花粉母细胞的 2-D 感知而被隐藏。在涉及黑麦花药操作的任何研究中，都不能忽视核间核迁移。
