ARS | Publication request: Fructan mobilization during recovery from freezing in winter oat crowns

Submitted to: International Fructan Conference
Publication Type: Proceedings
Publication Acceptance Date: July 25, 2008
Publication Date: July 27, 2008
Citation: Livingston, D.P., Tuong, T.D. 2008. Fructan mobilization during recovery from freezing in winter oat crowns. International Fructan Conference. pg 28.

Technical Abstract: Fructan, which is a carbohydrate polymer similar to starch but based on fructose, is an important cryoprotectant in plants. But how the plant uses this carbohydrate to improve freezing resistance is controversial. We are reporting here results of the first analysis of fructan changes that occur during recovery from freezing, prior to the formation of new leaves when the plant begins to photosynthesize again. Using light microscopy, we identified 4 zones within the lower stems (crown) of winter cereals that differ in freeze-induced damage. Here we present results from oat, the least hardy winter cereal crop. We dissected these 4 zones of the crown and quantified fructan and the sugars, fructose, glucose and sucrose in each. Fructan was significantly more concentrated in the uppermost part of the crown called the apical meristem than it was in any of the 4 zones and during the first 7 days of recovery this fraction decreased to a greater extent than any other carbohydrate. These results suggest that fructan mobilization during recovery from freezing is an important part of overall winter hardiness and may explain discrepancies in past studies between fructan content and freezing tolerance of winter cereal cultivars and species. In addition, the biggest changes in CHO reallocation occurred in the first 3 days after freezing. This suggests that to better understand the metabolism of plants recovering from freezing a more detailed analysis should concentrate on tissue immediately after freezing.