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Histopathology of Monilinia laxa on plum fruits
Thesis (M. Sc.) -- University of Stellenbosch, 1994.
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| Format: | Thesis |
| Language: | English |
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Stellenbosch : Stellenbosch University
2012
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| _version_ | 1867614059897028608 |
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| access_status_str | Open Access |
| author | Den Breeyen, Alana |
| author2 | Lennox, C. L. |
| author_browse | Den Breeyen, Alana Lennox, C. L. |
| author_facet | Lennox, C. L. Den Breeyen, Alana |
| author_sort | Den Breeyen, Alana |
| collection | Thesis |
| dc_rights_str_mv | Stellenbosch University |
| description | Thesis (M. Sc.) -- University of Stellenbosch, 1994. |
| format | Thesis |
| id | oai:scholar.sun.ac.za:10019.1/58433 |
| institution | Stellenbosch University (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:46:01.452Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from SUNScholar — Stellenbosch University Repository |
| publishDate | 2012 |
| publishDateRange | 2012 |
| publishDateSort | 2012 |
| publisher | Stellenbosch : Stellenbosch University |
| publisherStr | Stellenbosch : Stellenbosch University |
| record_format | dspace |
| source_str | SUNScholar — Stellenbosch University Repository |
| spelling | oai:scholar.sun.ac.za:10019.1/58433 Histopathology of Monilinia laxa on plum fruits Den Breeyen, Alana Lennox, C. L. Stellenbosch University. Faculty of AgriScience. Dept. of Plant Pathology. Brown rot fungi of fruit Monilinia laxa Fungal diseases of plants Plum -- Diseases and pests Dissertations -- Plant pathology Thesis (M. Sc.) -- University of Stellenbosch, 1994. Microreproduction of original thesis. Brown rot caused by Monilinia laxa is one of the most important diseases of stone fruit, including the plum. Economic losses due to M. laxa are estimated at 30%–50% fruit loss, particularly during optimum disease conditions. The mode of penetration of M. laxa on stone fruit, including the plum, has not been well documented. This study was undertaken to investigate the histopathology of M. laxa on the surface of plum fruits. Epidermal and morphological characteristics of the plum were investigated to determine the role they played in the resistance of plum fruit to M. laxa. The rate of lesion development on artificially wounded plums was determined to ascertain the value of lesion diameters as a measure of resistance. Light and scanning electron microscope studies showed that conidia germinated readily on the surface of fruit picked at both phenological times. Appressorium formation was not observed. Germinating conidia remained embedded under the epicuticular wax and this could possibly increase their chances of surviving extended periods of unfavourable conditions and finding suitable sites for penetration. The pathogen entered both stomata and microcracks, but further growth in the fruit tissue was not observed. No evidence of direct penetration of hard- or full-ripe fruit was found. Stomatal and lenticel decolouration at the inoculation site was recorded indicating a host reaction to M. laxa. The similarity in morphology of the epicuticular wax layer between the four cultivars studied would indicate that the differences in the expression of resistance to M. laxa cannot wholly be attributed to the wax layer, although it can be assumed to be a contributing factor in the overall resistance of these cultivars. No significant differences in cuticle and skin thickness measurements for the 1991/92 season were found although there were significant differences between cultivars for the 1992/93 season. The inoculation of artificially wounded fruit is a successful means of obtaining different degrees of resistance in the case of the four plum cultivars. From this study it is evident that M. laxa is unable to directly penetrate healthy plum fruit and cause decay. Its inability to successfully penetrate directly through the intact cuticle could possibly be due to resistance in the plum fruit to penetration by M. laxa or to the inability of the pathogen to form infection structures and colonise underlying tissue. The study verifies previously reported observations that M. laxa is primarily a wound pathogen. Masters 2012-08-27T11:38:58Z 2012-08-27T11:38:58Z 1994 Thesis http://hdl.handle.net/10019.1/58433 en Stellenbosch University 46 pages : ill. application/pdf Stellenbosch : Stellenbosch University |
| spellingShingle | Brown rot fungi of fruit Monilinia laxa Fungal diseases of plants Plum -- Diseases and pests Dissertations -- Plant pathology Den Breeyen, Alana Histopathology of Monilinia laxa on plum fruits |
| title | Histopathology of Monilinia laxa on plum fruits |
| title_full | Histopathology of Monilinia laxa on plum fruits |
| title_fullStr | Histopathology of Monilinia laxa on plum fruits |
| title_full_unstemmed | Histopathology of Monilinia laxa on plum fruits |
| title_short | Histopathology of Monilinia laxa on plum fruits |
| title_sort | histopathology of monilinia laxa on plum fruits |
| topic | Brown rot fungi of fruit Monilinia laxa Fungal diseases of plants Plum -- Diseases and pests Dissertations -- Plant pathology |
| url | http://hdl.handle.net/10019.1/58433 |
| work_keys_str_mv | AT denbreeyenalana histopathologyofmonilinialaxaonplumfruits |