title: Multiple bud cultures of 'Barhee' date palm (Phoenix dactylifera) and physiological status of regenerated plants.
abstract: Adventitious bud clusters of date palm 'Barhee' were successfully established from juvenile leaves (<1cm) using reduced amounts of 2,4-D (0.2mgL(-1)) to limit the risk of somaclonal variation. An average of 8.4 adventitious buds per explant were obtained. Histological examination showed that the superficial cell layers of leaves had the highest caulogenic capacity. High sucrose concentration (70gL(-1)) was used for the conversion of initial buds to multiple bud clusters. The promoting effect of temporary immersion on shoot proliferation was found to be significant when compared to cultivation on solid media. Elongation of shoots was also better using a thin film of PGR-free liquid medium instead of a solid medium. Anatomical observations indicated that roots from vitroplants were potentially functional at various developmental stages. However, only 12-month-old vitroplants were found to be physiologically able to control transpirational vapor loss. Additionally, the photochemical activity of photosystem II in these vitroplants was close to that measured in plants that were already acclimatized. As a result, 83.3% of regenerated plants were successfully acclimatized. No phenotypic variation was observed among more than 500 adventitious bud-derived plants. All regenerants survived after field transplantation. We found that the production of adventitious bud clusters in small bioreactors was able to provide an efficient micropropagation system for date palm cv. 'Barhee'. An in vitro hardening step was a prerequisite for the successful transfer of vitroplants in soil.
authors.affiliation: Laboratory of Plant Biotechnology, Faculty of Sciences of Sfax, University of Sfax, Route Sokra, BP 1171, 3000 Sfax, Tunisia. lotfi.fki@fss.rnu.tn
authors.forename: Lotfi
authors.initials: L
authors.lastname: Fki
authors.forename: Neila
authors.initials: N
authors.lastname: Bouaziz
authors.forename: Walid
authors.initials: W
authors.lastname: Kriaa
authors.forename: Raja
authors.initials: R
authors.lastname: Benjemaa-Masmoudi
authors.forename: Radhia
authors.initials: R
authors.lastname: Gargouri-Bouzid
authors.forename: Alain
authors.initials: A
authors.lastname: Rival
authors.forename: Noureddine
authors.initials: N
authors.lastname: Drira
mesh_terms: D015084:2,4-Dichlorophenoxyacetic Acid / Q000494:pharmacology; D000064:Acclimatization; D028023:Arecaceae / Q000187:drug effects / Q000254:growth & development / Q000502:physiology* / Q000648:ultrastructure; D003470:Culture Media; D010788:Photosynthesis; D018515:Plant Leaves / Q000254:growth & development / Q000648:ultrastructure; D018517:Plant Roots / Q000254:growth & development / Q000648:ultrastructure; D018520:Plant Shoots / Q000254:growth & development / Q000648:ultrastructure; D012038:Regeneration; D013395:Sucrose / Q000494:pharmacology; D046509:Tissue Culture Techniques / Q000379:methods*
chemical_list: D003470:Culture Media; D015084:2,4-Dichlorophenoxyacetic Acid; D013395:Sucrose