The ontogeny and (ultra)structure of vascular tissue in Lupinus luteus L. root nodules were studied by light and transmission electron microscopy in juvenile nodule primordia up to the 11th day after inoculation. Vascular meristem originated from centripetally dedifferentiated root cortical parenchyma, endodermis and pericycle. The vascular trace was formed between bacteroid tissue initials and the root stele. In the trace's proximal part, cambial strands connecting the vascular trace and root cambium were formed. In the distal part, non-anastomosing vascular bundles started differentiating from the trace at the end of the juvenile stage. In lupine, the formative stage of the indeterminate root nodule vascular system was shown to be unique within the legumes.
The development and (ultra)structure of vascular tissue was studied in Lupinus luteus L. mature root nodules 25 and 60 days after inoculation. In the proximal part of the nodule vascular trace, extensive growth took place to match the secondary growth of the root. Development of bacteroid and vascular tissues was correlated. The non-anastomosing nodule vascular bundles elongated and branched due to the activity of nodule lateral meristems, thus forming an extensive vascular network within deep lobes of bacteroid tissue. The vascular trace and vascular bundles differed mainly in the location and ultrastructure of transfer cells and parenchymatous cells, in which the inner membrane of the nuclear envelope formed tubular invaginations within the dense chromatin. Development of the vascular system in the collar root nodule of lupine differed from that of cylindrical indeterminate nodules.
Six seedling hypocotyl anatomical characters of sugar beet diploid lines and triploid hybrids were measured. Root yield and sugar content of these lines and hybrids were evaluated in replicated field trials. Some of the studied hypocotyl characters: the diameter of the central core, the diameter of parenchymatic cells outside the central core and the width of xylem, correlated negatively with sugar content and positively with root yield. This suggests that these parameters can be used in preliminary selection of sugar-beet breeding material. Introducing such criteria into the breeding process could speed up the selection and reduce the number of expensive field trials.