Peach Tree Short Life (PTSL) is a syndrome characterized by a collapse of the peach trees (Prunus persica (L.) Batsch) during the flowering, or in the beginning of the bud break period, after a drastic reduction of the temperature. The aim of the present work was to determine the peroxidase activity (UE min-1 g-1 MF) during the dormancy period in buds and twigs tissues of peach trees cv. Jubileu with and without PTSL symptoms. Two experiments were conducted separately, one for each appraised tissue, in two peach orchards with four years of implantation, both located in the colonial region of Pelotas, RS, in the Santa Helena and Cascata districts. The tissues consisted in buds and twigs collected in four dates during the dormancy period (June 11th, July 11th, July 29th, and August 05th) in 2003. The peroxidase activity determinations were carried out at the Vegetal Physiology Laboratory of Embrapa Clima Temperado. The plants with symptoms of PTSL showed higher peroxidase activity than the healthy plants along the dormancy period in both tissues analyzed. The syndrome triggering could lead to the dormancy interruption and the premature exposition of the new tissues to the injuries caused by the low temperatures during the winter. Moreover, the population levels of ring nematode (Mesocriconema xenoplax) and of the Helicotylenchus sp. found in the soil of plants with symptoms of PTSL were higher than plants without symptoms, resulting also in the higher peroxidase activity in both tissues (twigs and buds) during the rest period of the attached plants.
Prunus persica; decline; oxidative stress; dormancy; nematodes
