Condutância hidráulica de cultivares copa de Prunus spp. em função do porta-enxerto, na região de Pelotas – RS

Abstract

Rio Grande do Sul is responsible for over 60% of the national production of stone fruits. However, it faces challenges in achieving high average yields due to factors such as water stress, which is associated with the premature death syndrome in plants. One strategy to enhance productivity and mitigate the effects of water stress is the use of selected rootstocks. This study focused on characterizing the xylem vessels and their correlation with hydraulic conductivity loss in peach and plum plants based on the rootstock used. Peach trees of the 'BRS Rubimel' variety were grafted onto rootstocks 'Capdeboscq', 'Flordaguard', and 'Okinawa Roxo'. Similarly, plum trees of the 'Reubennel' variety were grafted onto 'Okinawa' and 'Myrobalan 29C' rootstocks, with comparisons made against self-rooted 'Reubennel' plants. The analysis encompassed xylem vessels in both branches and roots, as well as the measurement of hydraulic conductivity loss and its relationship with precipitation patterns. The experiment with peach trees demonstrated high percentages of loss hydraulic conductivity (PLC) due to prolonged drought periods. In February 2022, the PLC reached approximately 45%, indicating a moderate level of cavitation potential. Nonetheless, there was no significant risk of irrecoverable damage to xylem conductivity, suggesting good resistance to water stress in the evaluated plant combinations. By February 2023, PLC in 'BRS Rubimel' peach trees exhibited lower and comparable averages to those observed in the second experiment involving 'Reubennel' plum trees that were not subjected to water deficit conditions. Grafted plants exhibited higher PLC averages than self-rooted plants, attributed to the grafting process. Moreover, the narrowing of xylem vessels in the branches ensures hydraulic safety and sustains water transport efficiency despite reduced capacity. These findings highlight that the use of selected rootstocks can enhance productivity and alleviate water stress effects in peach and plum orchards in Rio Grande do Sul. Furthermore, histological analyses of xylem vessels can be valuable in selecting appropriate rootstocks for the cultivation of these fruit-bearing trees.