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Acta Horticulturae
Philosoph-Hadas, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Perzelan, Y., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Droby, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Shtein, I., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Salim, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Meir, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Bar-Tal, A., Department of Soil Chemistry, Agricultural Research Organization (ARO), Volcani Center, Israel
Branches of Pittosporum (Pittosporum tobira Thunb. 'Variegata') with variegated leaves are very popular in the cut foliage industry as bouquets fillers. However, their quality is compromised due to brown spots appearing mainly on the white sectors of the variegated leaves, with subsequent development of various pathogens on the necrotic area. This physiological disorder appears already in the field, and is aggravated following prolonged sea transport from Israel to USA (3-4 weeks at 2°C). Our survey performed among various Pittosporum growers showed, that increased appearance of brown spots in the field was associated with a rapid vegetative growth under red nets, which may lead to nutrient deficiency, with poorly drained or wet and heavy soil, poor ventilation and increased plot age. Increased leaf browning, observed under red nets compared to black nets at the same light intensity, was accompanied with reduced water uptake of the cut branches, indicating that increased water uptake may reduce leaf browning. Examination of leaf anatomy revealed that the white sectors of the variegated leaf blades have lower densities and thickness of palisade cells than the fully green sectors, and have a 30% higher stomata density. This suggests that the white leaf sectors are more susceptible to water loss and radiation stress. The brown spots examined under UV light indicated the possible involvement of oxidized polyphenols, resulting in leaf browning and tissue necrosis. Indeed, postharvest pulsing treatments with an antioxidant, reduced glutathione (GSH), alleviated the incidence of the browning symptoms following sea transport simulation to USA. Analysis of macro and micro nutrients revealed that affected leaves had significantly lower levels of N and K, but higher levels of Ca, Na and Cu as compared with healthy leaves. It is possible that changes in these essential nutrients may increase the levels of reactive oxygen species (ROS), thereby leading to oxidation of the polyphenols in the white leaf sectors, and rendering them more susceptible to the development of brown spots.
פותח על ידי קלירמאש פתרונות בע"מ -
הספר "אוצר וולקני"
אודות
תנאי שימוש
Pittosporum cut branches: Characterization and prevention of the brown spots on the variegated leaves during growth and sea transport
970
Philosoph-Hadas, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Perzelan, Y., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Droby, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Shtein, I., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Salim, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Meir, S., Department of Postharvest Science of Fresh Produce, Agricultural Research Organization (ARO), Volcani Center, Israel
Bar-Tal, A., Department of Soil Chemistry, Agricultural Research Organization (ARO), Volcani Center, Israel
Pittosporum cut branches: Characterization and prevention of the brown spots on the variegated leaves during growth and sea transport
Branches of Pittosporum (Pittosporum tobira Thunb. 'Variegata') with variegated leaves are very popular in the cut foliage industry as bouquets fillers. However, their quality is compromised due to brown spots appearing mainly on the white sectors of the variegated leaves, with subsequent development of various pathogens on the necrotic area. This physiological disorder appears already in the field, and is aggravated following prolonged sea transport from Israel to USA (3-4 weeks at 2°C). Our survey performed among various Pittosporum growers showed, that increased appearance of brown spots in the field was associated with a rapid vegetative growth under red nets, which may lead to nutrient deficiency, with poorly drained or wet and heavy soil, poor ventilation and increased plot age. Increased leaf browning, observed under red nets compared to black nets at the same light intensity, was accompanied with reduced water uptake of the cut branches, indicating that increased water uptake may reduce leaf browning. Examination of leaf anatomy revealed that the white sectors of the variegated leaf blades have lower densities and thickness of palisade cells than the fully green sectors, and have a 30% higher stomata density. This suggests that the white leaf sectors are more susceptible to water loss and radiation stress. The brown spots examined under UV light indicated the possible involvement of oxidized polyphenols, resulting in leaf browning and tissue necrosis. Indeed, postharvest pulsing treatments with an antioxidant, reduced glutathione (GSH), alleviated the incidence of the browning symptoms following sea transport simulation to USA. Analysis of macro and micro nutrients revealed that affected leaves had significantly lower levels of N and K, but higher levels of Ca, Na and Cu as compared with healthy leaves. It is possible that changes in these essential nutrients may increase the levels of reactive oxygen species (ROS), thereby leading to oxidation of the polyphenols in the white leaf sectors, and rendering them more susceptible to the development of brown spots.
Scientific Publication
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