Paclobutrazol Reduces Some Negative Effects of Salt Stress in Peach

Abstract

One-year-old rooted cuttings of `Nemaguard' peach [Prunus persica (L.) Batsch.] were irrigated with 0, 1000, or 2000 mg·L-1 salts under greenhouse conditions to study the effect of foliar paclobutrazol (PBZ) application on salt stress response. Salinity reduced growth of nontreated plants by ≈60%, but only by ≈30% for PBZ-treated plants. PBZ-treated plants also had less defoliation and fewer leaves per plant showing salt stress symptoms, and had higher rates of leaf gas exchange than nontreated plants. PBZ application generally reduced Na+ and Cl- contents in leaves, roots, and stems, regardless of salt treatment. Furthermore, total Na+ per plant in PBZ-treated plants was about half that found in nontreated plants, although total Cl- per plant was reduced by PBZ in only one of two salt treatments. The data suggested that PBZ promoted salt stress avoidance in peach by reducing the uptake and accumulation of harmful Na+ and Cl- ions in plant tissues.