Background and Aims
During an 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 3D structure of rye meiocytes throughout meiosis.
Methods
We used two types of volume light microscopy: confocal laser scanning microscopy and non-confocal brightfield scanning microscopy combined with alcohol and aldehyde fixation as well as serial block-face scanning electron microscopy.
Key Results
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 micronuclei 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.
Conclusions
INM 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 two-dimensional perception of plant male meiocytes. INM cannot be ignored in any studies involving manipulations of rye anthers.
