| dc.description.abstract | The objective of this work was the anatomical description of the rhizogenesis of minicuttings,
from clones selected from the adventitious rooting of A. mearnsii (black wattle) and I.
paraguariensis (yerba mate), as well as to bring new insights on how barriers can affect
adventitious rooting. For this purpose, anatomical characteristics of semi-hardwood
minicuttings clones of A. mearnsii and I. paraguariensis treated with indolbutyric acid (IBA),
grown in polyethylene trays with commercial substrate based on pine bark, coarse grained
sand and medium vermiculite were analyzed. , kept in a humid chamber. Black wattle minicuttings
(B5, AB6, A1845) were collected at intervals of 0, 1, 5, 10, 15 and 30 days and yerba
mate clones (13SM05, 10SM07, 06SM15) were collected at 0, 30 and 60 days. Histochemical
tests were performed to detect the presence of starch, and primary and secondary metabolites
with rhizogenesis. The place of origin of the root primordia was verified. The general results
contributed to understand the rooting process of both species, and black wattle, regardless of
the sclerenchyma layer in the phloem region, was not an anatomical barrier here for the
present study, since the formation of roots occurred in a endodermal proliferation, vascular
tissue and primary and secondary phloem activity to form new cells. In black wattle, it was
also verified that the absence of tissue, due to the occurrence of fungi in the first hours of
cultivation, appeared as such an environmental barrier, for these studied clones. In yerba
mate, the presence of starch in abundance was remarkable in clones with greater rooting
competence, whereas for black wattle it was indifferent. He also observed that small
differences between species may be associated with the response speed for adventitious
rooting. However, the formation of adventitious roots in both species and studied clones
showed similarity, from callus formation, adventitious vascularization and root formation by
the indirect pattern. Therefore, for both studied species, rhizogenesis presented barriers, but
these are not necessarily anatomical. | |
