AOBPreview originally published online on May 13, 2005
Annals of Botany 2005 96(2):331-335; doi:10.1093/aob/mci167
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Published by Oxford University Press on behalf of the Annals of Botany Company 2005
Carbohydrate Concentrations in Crown Fractions from Winter Oat during Hardening at Sub-zero Temperatures
1 USDA and North Carolina State University, 840 Method Road, Unit 3, Raleigh, NC 27695, USA, 2 USDA and North Carolina State University, 3127 Ligon Street, Raleigh, NC 27607, USA and 3 North Carolina State University, 840 Method Road, Unit 3, Raleigh, NC 27695, USA
* For correspondence. E-mail dpl{at}unity.ncsu.edu
Received: 28 September 2004 Returned for revision: 8 November 2004 Accepted: 29 March 2005 Published electronically: 13 May 2005
Background and Aims Contradictory results in correlation studies of plant carbohydrates with freezing tolerance may be because whole crown tissue is analysed for carbohydrates while differences exist in the survival of specific tissue within the crown. The aim of this study was to see if carbohydrate changes in tissue within oat crowns during second phase hardening (sub-zero hardening) are tissue specific.
Methods The lower portion of oat (Avena sativa) crowns was exposed to mild grinding in a blender and the remaining crown meristem complex, consisting of tough root-like vessels, was ground in a device developed specifically for grinding cereal crown tissue. Carbohydrates were extracted by water and measured by HPLC. Carbohydrate concentrations were compared in the two regions of the crown before and after hardening at sub-zero temperatures.
Key Results Fructan of all size classes except DP>6 decreased during sub-zero hardening in both stems (base of leaf sheath) and crown meristem complex. Total simple sugar increase, including sucrose, was significantly higher in the crown meristem complex than in the stem.
Conclusions Results support the hypothesis that carbohydrate change in mildly frozen plants is tissue specific within crowns and underscore the need to evaluate specific tissue within the crown when correlating the biochemistry of plants with freezing tolerance.
Key words: Freezing tolerance, crown tissue, oat, Avena sativa, carbohydrates, fructan, apical meristem