In vitro culture techniques are widely used in potato for rapid production of specific pathogen tested plantlets and microtubers, which are essential for seed certification programs. The limited calcium (Ca) uptake in vitro promotes physiological disorders in many micropropagated species including potato. Factors that may affect Ca uptake by potato plantlets, including cations, osmotic potential, and boron (B) were examined. The possibility of improving microtuber yield by low pH shock or successive harvests, which stimulated greenhouse potato production, were also investigated. Ca uptake by cvs. Norland and Bintje potato plantlets grown on modified Murashige and Skoog (MS, 1962) media was enhanced by diluting the total macroelements in the nutrient medium, except Ca. Increasing Ca:specific cation ratios, by lowering either NH 4, Mg or K, had little effect on Ca uptake by Norland plantlets. At equivalent Ca:total cation, Ca uptake was promoted further when the total macroelement concentration was reduced by half than when the Ca level was doubled (from 3 to 6 mM). This suggested that the increase in the osmotic potential of the medium had a great impact on Ca uptake, probably by affecting the root pressure. B contamination from impurities in the nutrient chemical components always occurred. The addition of the recommended H3BO 3 level of 0.1 mM (1.08 ppm) or more (0.3 mM) to the medium decreased Ca content of leaves and shoots in Norland but not Bintje, while addition of only 25% of this level was sufficient to provide plantlets with adequate B tissue concentration without compromising normal growth. Macroelement dilution along with Ca addition, and lower B levels than commonly used in MS (0.1 mM) are recommended for optimal Ca uptake in potato and possibly other plant species. Microtuber yield was not improved by a low pH shock. Adjusting microtuberization medium pH to less than 5.7 (3.5, 4.3 or 5.2), prior to autoclaving, reduced microtuber number and/or weight
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.35671 |
| Date | January 1998 |
| Creators | Abdulnour, Jihad. |
| Contributors | Barthakur, N. N. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Natural Resource Sciences.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001657867, proquestno: NQ50098, Theses scanned by UMI/ProQuest. |
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