|Reyes-Vera, Isaac - NEW MEXICO STATE UNIV|
Submitted to: Australian Journal of Botany
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 28, 2008
Publication Date: July 1, 2008
Citation: Reyes-Vera, I., Potenza, C.L., Barrow, J.R. 2008. Hyperhydricity reversal and clonal propagation of four-wing saltbush (atriplex canescens, Chenopodiaceae) cultivated in vitro. Australian Journal of Botany. 56:358-362. Interpretive Summary: Fourwing saltbush is a valuable forage and reclamation shrub in arid ecosystems world wide. Standard culture systems yield abnormal regenerated plants that do not develop into normal plants. This research shows that by altering nitrogen sources and culturing in vented vessels, this problem is reduced and substantial numbers of plants can be produced for remediation projects. The results will provide solutions for similar problems encountered in the propagation of woody plants.
Technical Abstract: In vitro propagated shoots of four-wing saltbush [Atriplex canescens (Pursh Nutt)] showed severe symptoms of hyperhydricity. Hyperhydricity is a frequent physiological problem reported in micropropagation of A. canescens and other plant species, and drastically reduces the quality of in vitro cultures. It is exacerbated when plants are cultured in airtight culture vessels on medium formulations with high nitrogen concentrations. We show that the reversion of hyperhydric A. canescens shoots to normal shoots was significantly affected by the presence of inorganic nitrogen in the culture vessel. When the culture vessel was vented or when ammonium nitrate was deleted from Murashige and Skoog basal medium, rates of reversion were significantly higher. While statistically significant differences were evident when comparing vented vs. non-vented treatments for each medium, the modified culture medium with vented closures was consistently the best treatment, showing a total cumulative frequency of 39.7% compared with a total cumulative frequency of 7.1 % observed in the control treatment. Resulting normal shoots also showed significant improvements in further manipulations, including rooting in vitro, transplantation to soil, and survival in native sites.