Influence of Tendrils and IBA on Rhizogenic Responses in Cuttings of Black Pepper Cultivars: Histological and Histochemical Aspects

The Black pepper (Piper nigrum L.) is appreciated worldwide for its pleasant aroma and spicy flavor. New plants are established by vegetative propagation of stem cuttings and addition of growth regulators to improve rooting. Here, we aimed to evaluate the influence of tendrils and indole-3-butyric acid (IBA) on the anatomy and adventitious rooting of cuttings from three black pepper cultivars, namely 'Bragantina', 'Guajarina', and 'Iacara'. The following variables were assessed: survival percentage; sprouting; total, basal, and nodal rooting; number and length of basal, nodal, and total roots; and total root volume. The highest rooting rates (76.4%) were recorded in IBA-treated cuttings lacking tendrils, highlighting the potential of 'Guajarina' (81.1%) and 'Iacara' (78.6%). Histological analyses revealed the presence of perivascular fibers and lignification of the collenchyma, which might have restrained rhizogenesis in the cuttings. Histochemical analysis revealed reduced levels of starch in the cuttings of 'Bragantina', which might explain the significantly low rooting rates, with starch concentration described by the color code as common in the pith and rare in the cortex, phloem and xylem.

Automated summary

This study evaluated the influence of tendrils and indole-3-butyric acid (IBA) on the anatomy and adventitious rooting of cuttings from three black pepper cultivars. Results showed that IBA-treated cuttings without tendrils had the highest rooting rates. Histological and histochemical analyses revealed some anatomical characteristics and starch content in the cuttings were related to rooting rates.