PREVENTION OF BROWNING OF LEAVES OF PROTEA NERIIFOLIA R. Br.

Ferreira, D. I.

doi:10.17660/actahortic.1983.138.31

Cited by 7 publications

(5 citation statements)

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“…A rapid blackening of the foliage is a commercially important postharvest problem with some species of Protea (Ferreira, 1983). Within a few days of harvest, the leaves become limp and leathery; a day or two later black areas develop, so that within 8 days of harvest most leaves can be completely black.…”

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confidence: 99%

Carbohydrate Changes and Leaf Blackening in Cut Flower Stems of Protea eximia

Bieleski¹,

Ripperda²,

Newman³

et al. 1992

jashs

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We tested the hypothesis that premature leaf blackening in cut flower stems of Protea eximia (Salisb. ex Knight) Fourcade may be brought about by a low leaf carbohydrate status. Leaves on cut flower stems held in darkness blackened within 4 days, whereas those on stems held in a greenhouse remained healthy for 5 days. Leaf blackening was also retarded by supplying 1% sucrose in the vase solution; but other additives (hypochlorite, silver thiosulfate, bisulfite) were not effective. The hypothesis was further explored by examining postharvest carbohydrate changes in the leaf of cut flower stems held in light or darkness. At harvest, leaves contained very little hexose (< 1 mg·g-1 fresh weight), comparatively small concentrations of sucrose (≈ 5 mg·g-1 fresh weight) and starch (≈ 6 mg·g-1fresh weight), but high concentrations (≈ 30 mg·g-1fresh weight) of the polyol polygalatol. Starch and sugar contents of leaves held in darkness fell rapidly, to one-third of their initial level after only 1 day and to one-sixth after 3 days. In contrast, starch and sugar contents increased slowly in leaves of stems held in light to three times the initial level after 3 days. Polygalatol content was unaffected by any treatment. Removal of the inflorescence did not delay blackening of leaves held in darkness and did not affect their carbohydrate changes.

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confidence: 99%

Carbohydrate Changes and Leaf Blackening in Cut Flower Stems of Protea eximia

Bieleski¹,

Ripperda²,

Newman³

et al. 1992

jashs

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“…Many Proteaceous species have become important "cut-flower crops. A major postharvest problem of this genus, in particular Protea neriifolia and P. eximia, is premature blackening of the leaves (Brink and de Swardt, 1986;Ferreira, 1983;Newman et al, 1989;Paull et al, 1980). Leaves of susceptible species begin to turn black within 3 to 7 days after harvest, severely reducing the market value of a flower stem that otherwise has a potential vase life of 3 to 4 weeks.…”

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Carbohydrate Depletion and Leaf Blackening in Protea neriljiolia

McConchie¹,

Lang²,

Gross³

1991

jashs

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Leaf blackening on cut flower Protea nerii[olia R. Br. stems was dramatically reduced under a 12-hour photosynthetic light period (120 μmol·m-2·s-1) at 25C for 15 days compared with stems kept in the dark. In the light, addition of 0.5% exogenous sugar to the vase solution resulted in a maximum of 2.5% leaf blackening, while stems with no exogenous sugar had a maximum of 16.5%. Continuous darkness resulted in 94% leaf blackening by day 7, irrespective of sugar treatment. Starch and sucrose concentrations were markedly lower in leaves on dark-held stems than in leaves on stems held in the light; thus, carbohydrate depletion could be the primary stress that initiates leaf blackening. In the light, rates of carbon exchange and assimilate export were similar, indicating that the amount of carbon fixed maybe regulated by sink demand. The pattern of carbon partitioning changed in light-held leaves of the 0% sugar treatment during rapid floral expansion and senescence. Inflorescence expansion appears to influence partitioning of photoassimilates and storage reserves into transport carbohydrates; under decreased sink demand, the assimilate export rate decreases and photoassimilates are partitioned into starch. The data suggest that sink strength of inflorescences held in darkness may be responsible for the depletion of leaf carbohydrates and. consequently, blackening.

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“…Table grape browning appears mainly as a discoloration of the pulp (flesh or internal browning) and berry skin (skin or external browning) (Vial et al, 2005). This is due to a dysfunction or disruption of the cellular membranes, which allows the mixing of the enzyme polyphenol oxidase (PPO) with phenolic substrates or compounds occurring naturally in the fruit (Ferreira, 1997;Golding et al, 1998;Kruger et al, 1999). Several different phenotypes of browning, such as external, internal, low temperature, chemical, physical, and pathogenic browning have been identified by Fourie (2009).…”

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confidence: 99%

Classification of Browning on Intact Table Grape Bunches Using Near-Infrared Spectroscopy Coupled With Partial Least Squares-Discriminant Analysis and Artificial Neural Networks

et al. 2021

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Table grape browning is a complex physiological disorder that occurs during cold storage. There is a need to investigate novel and innovative ways to manage the problem that hampers the progressive and sustainable growth of table grape industries. Given the complex nature of the browning phenomenon, techniques such as near-infrared (NIR) spectroscopy can be utilized for the non-destructive classification of different browning phenotypes. In this study, NIR coupled with partial least squares discriminant analysis (PLS-DA) and artificial neural networks (ANN) were used to classify bunches as either clear or as having chocolate browning and friction browning based on the spectra obtained from intact ‘Regal Seedless’ table grape bunches that were cold-stored over different periods. Friction browning appears as circular spots close to the pedicel area that are formed when table grape berries move against each other, and chocolate browning appears as discoloration, which originates mostly from the stylar-end of the berry, although the whole berry may appear brown in severe instances. The evaluation of the models constructed using PLS-DA was done using the classification error rate (CER), specificity, and sensitivity and for the models constructed using ANN, the kappa score was used. The CER for chocolate browning (25%) was better than that of friction browning (46%) for weeks 3 and 4 for both class 0 (absence of browning) and class 1 (presence of browning). Both the specificity and sensitivity of class 0 and class 1 for friction browning were not as good as that of chocolate browning. With ANN, the kappa score was tested to classify table grape bunches as clear or having chocolate browning or friction browning and showed that chocolate browning could be classified with a strong agreement during weeks 3 and 4 and weeks 5 and 6 and that friction browning could be classified with a moderate agreement during weeks 3 and 4. These results open up new possibilities for the development of quality checks of packed table grape bunches before export. This has a significant impact on the table grape industry for it will now be possible to evaluate bunches non-destructively during packaging to determine the possibility of these browning types being present when reaching the export market.

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PREVENTION OF BROWNING OF LEAVES OF PROTEA NERIIFOLIA R. Br.

Cited by 7 publications

References 0 publications

Carbohydrate Changes and Leaf Blackening in Cut Flower Stems of Protea eximia

Carbohydrate Changes and Leaf Blackening in Cut Flower Stems of Protea eximia

Carbohydrate Depletion and Leaf Blackening in Protea neriljiolia

Classification of Browning on Intact Table Grape Bunches Using Near-Infrared Spectroscopy Coupled With Partial Least Squares-Discriminant Analysis and Artificial Neural Networks

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