Spatial and temporal dynamics of peroxidase and amine oxidase activity is linked to polyamines and lignin in wheat grains

Abstract

The regulation of contents and activities of peroxidase (POX), diamine oxidase (DAO) and polyamine oxidase (PAO) were determined in relation to polyamines and lignin content in wheat (Triticum aestivum L.) grains. Two cultivars WH 542 (heat susceptible) and PBW 343 (heat tolerant) were used. Activities of POX, DAO and PAO were substantially higher in PBW 343 as compared with WH 542 and appeared to be independently regulated. POX and PAO showed peak activities at mid-milky stage (15 d post anthesis) while the activity of DAO showed continuous decline. Histochemical localization of POX and PAO in situ revealed their presence in the chalazal cell walls, crease and seed coat. Substantially higher activities of enzymes in PBW 343 correlated well with a higher degree of lignification in the chalazal cells as compared to WH 542.

Keywords

• diamine/polyamine oxidase
• lignification
• triticum aestivum