Bladderworts (Utricularia, Lentibulariaceae) possess an extra-ovular female gametophyte that penetrates the sporophytic tissue (placenta). Some parts of the placenta serve as ‘nutritive tissue’, providing nutrients to the female gametophyte and later to the endosperm. Płachno et al. studied the complexity of nuclei structures of ‘placenta nutritive tissue’ across eleven bladderwort species.
Płachno and colleagues used transmission electron microscopy (TEM) to visualize the complexity of the nuclear structures. They also made 3-D ultrastructural reconstructions, using the serial block face scanning electron microscopy (SBEM) technique. They examined the nuclei of 11 Utricularia species, i.e. U. nelumbifolia, U. reniformis, U. cornigera, U. nephrophylla (sect. Iperua), U. asplundii, U. alpina, U. quelchii (sect. Orchidioides), U. longifolia (sect. Foliosa), U. intermedia, U. minor and U. gibba (sect. Utricularia).
They observed unusual nuclei, with spindle-like tubular projections, in the placental tissue of Utricularia nelumbifolia. The authors call the placental nuclei structures ‘chromatubules’. Due to the apparent association with the plasma membrane and plasmodesmata, they speculate that chromatubules are involved in nucleus-to-cell-to-cell communication.
This paper is part of the Special Issue on Morphology and Adaptation. It is FREE access for a limited period to the end of January 2018. It will then be free access from November 2018.