Grafting relations in atemoya (Annona x atemoya Mabb.) plants: peroxidase and phenolic compounds

Abstract

The aim of this study was to evaluate if variations in the peroxidase activity (PRX) and the phenolic compounds (PC) concentration in atemoya scion (Annona x atemoya Mabb.) grafted onto different rootstocks are related to incompatibility. The experiment was conducted in a greenhouse, with atemoya scion grafted onto Annona species rootstocks [A. emarginata 'var. terra-fria'; A. emarginata 'var. mirim; A. mucosa and atemoya (homograft)] and these species ungrafted. The evaluations were performed at 30 and 60 days after grafting (DAG) in the hypocotyl region, where the grafting was performed, in each grafting combination and the same region corresponding to the stem tissue in ungrafted plants. The atemoya scion grafted onto A. mucosa showed higher PRX than A. mucosa ungrafted, although smaller than A. emarginata 'var. mirim' rootstock. In atemoya grafted onto A. emarginata 'var. fria' rootstock, no significant change in PRX compared to A. emarginata 'var. fria', atemoya ungrafted and homograft. The PC concentration at 30 DAG showed no significant differences in the grafted plants, although higher than in their respective ungrafted. At 60 DAG, no differences between grafted plants were observed, however, the PC concentrations in atemoya grafted onto A. emarginata 'var. terra-fria' and 'var. mirim' rootstocks were higher than those observed in A. emarginata 'var. terra-fria' and 'var. mirim' ungrafted, respectively. We concluded that variations in PRX and the PC are not related or triggered to incompatibility between atemoya scion grafted onto A. emarginata 'var. terra-fria', 'var. mirim ' and A. mucosa.

Peroxidase activity and initial growth of ‘Barbosa’ peach on clonal rootstocks

“…The higher peroxidase activity detected in the rootstock bark in relation to the scion bark, for several combinations (Table 1), can be attributed to the differences in the degree of lignification of tissues of both parts, considering that this enzyme acts on lignin biosynthesis (PASSARDI et al, 2005;NOCITO et al, 2010;ZARROUK et al, 2010;LIU, 2012;PINA et al, 2012;PEREIRA et al, 2013;FERNÁNDEZ-PÉREZ et al, 2015BARON et al, 2018. Plant lignification is a complex cellular process that occurs in three sequential steps: synthesis of monolignols in the cytosol; transport of monomeric precursors across the plasma membrane; and oxidative polymerization of monolignols to form lignin macromolecules within the cell wall (LIU, 2012).…”

“…Herrero et al (2014) reported that, although of great importance, high peroxidase activity cannot be considered as a definitive early diagnosis of incompatibility, since it seems to be more related to cell wall lignification rather than to tissue degradation. Therefore, the role played by peroxidases in lignification does not generally allow justifying the reason for graft incompatibility and should be proposed with caution (BARON et al, 2018).…”

“…Studies have been conducted to understand the involvement of peroxidase activity and phenolic compounds in graft compatibility, and participation in tissue lignification (PASSARDI et al, 2005; ZARROUK et al, 2010; LIU, 2012; PEREIRA et al , 2013; FERNÁNDEZ-PÉREZ et al, 2015;BARON et al, 2018), important in the early stages of connection between graft and rootstock ERREA, 2005;HARTMANN et al, 2011), because cell walls are dynamic structures composed of polysaccharides, proteins, minerals, and phenolic compounds such as lignin (HERRERO et al, 2014).…”