Anatomy and Histochemistry of Araticum (<i>Annona crassiflora</i> Mart.) on Three Annonaceae Rootstocks

Abstract

The cultivation knowledge about the Cerrado native fruits is incipient. These plants are found in wild conditions and its fruits are obtained through extraction, as the case of araticum ( Annona crassiflora Mart.), which is a species with the great economic potential. This plant propagation by grafting, among other methods, has proved problematic. Possible incompatibility causes were investigated using histochemical and anatomical studies. Transverse and longitudinal stems sections were analyzed in the araticum grafting area on rootstocks of araticum-de-terra-fria ( Annona emarginata (Schltdl.) H. Rainer “Terra-fria”), biribá ( Annona mucosa (Jacq.) Baill), and soursop ( Annona muricata L.). Araticum graft survival rate was low with these rootstocks, which seems to be associated with anatomical and histochemical factors. The periderm and pith are more developed in araticum than in the other plants, which affects the alignment and juxtaposition of the cambium and vascular bundles in the graft area, hindering a successful graft. The histochemical reactions for phenolic compounds detection were very strong in cortical parenchyma, pith and xylem fibers of araticum ( A. crassiflora ). The presence of phenolic compounds is increased depending on the cut for grafting and the formation of these compounds is evidenced as an important limiting factor for successful grafting. It is recommended practices for reducing these compounds and a larger diameter of the graft, as a mean to overcome these anatomical difficulties.