Autumn Acclimation and Carbon Metabolism in Miscanthus.

Miscanthus is a C4 perennial grass under consideration for the emerging bioeconomy in Ontario. Ontario’s short growing season, cold overwintering temperatures and spring frosts present a challenge to successful persistence and long-term productivity of Miscanthus. Miscanthus genotypes that have been observed to have higher winter survival rates are likely responding to shorter day lengths and decreasing temperatures in autumn with corresponding physiological and biochemical changes. It is hypothesized that genotypes with good cold tolerance will have rhizomes that undergo significant starch degradation and shifts in the contents of raffinose family oligosaccharides (RFO’s), and other sugars, known to confer increased cold tolerance.  A field experiment was initiated in mid June of 2010 and 2011 in Elora, ON to observe six Miscanthus genotypes; ‘Amuri’ and ‘Nagara’, two Nagara siblings ‘M118’ and ‘M119’ and two genotypes with lower observed winter survival, ‘M1-select’, and ‘M161’ in the first year of growth. The experiment was designed as a randomized complete block with four replications. Rhizomes were harvested four times between the end of September and the beginning of November in both years, and immediately immersed in liquid nitrogen and stored at -80^oC. Starch and sugars were tested at A&L Canada Laboratories Inc, London, ON. Sugars were analyzed using the raffinose/galactose assay procedure kit from MegaZyme International (Megazyme Int. Ireland Ltd., Bray, Ireland). Repeated measures and contrast analysis were used to examine the sugar profile data. The relative changes in the sugar profiles of field acclimated Miscanthus genotypes, will offer important insight into the cold tolerance mechanisms of this important biomass energy crop.