Stem and root anatomy of Mnesithea selloana (Hack.) de Koning & Sosef

MOYA, MARÍA ESTHER; GALUSSI, ALBERTO; SATTLER, NOELIA; FONTANA, SOLEDAD; GILLIJ, YANINA

PHYTON - INTERNATIONAL JOURNAL OF EXPERIMENTAL BOTANY BA ARGENTINA

FUNDACION ROMULO RAGGIO

Lugar: Buenos Aires; Año: 2018

0031-9457

Trabajo aceptado en mayo de 2018 para publicación (aún no publicado).The objective of this study was to analyze the anatomy of stems and roots of Mnesithea selloana. Free hand cross sections were made from fresh material of reproductive stems and adventitious roots; they were colored with safranin and mounted on glycerin jelly. Observations were made using an Olympus CH2 light microscope and photographed. In cross section, the stems are circular towards the distal end of the synflorescence and semicircular toward the proximal end, and have two ribs. A uniseriate, continuous epidermis presenting a smooth and thick cuticle and no hairs is observed. Parenchyma cells increase in size towards the pith; they have slightly thickened walls close to the epidermis and thin non-lignified walls near the pith. Vascular bundles form an atactostele, with 3-4 concentric rings; externally, small bundles enclosed within a continuous ring of sclerenchyma and toward the center, larger bundles without the ring are observed. The pith is hollow pith. The roots present rhizodermis with unicellular hairs, exodermis with markedly thickened walls, aerenchymatous parenchyma with well differentiated aeriferous spaces, and endodermal cells with markedly thickened inner tangential walls. The vascular cylinder presents uniseriate pericycle, with polyarch structure exhibiting between 13 and 16 xylematic poles, and pithy parenchyma.