PARENT SESSION
Poster Session #32: Plant Ecology I.
Wednesday, August 8, 2001. Presentation from 3:30 PM to 5:00 PM. Exhibition Hall

Variation in leaf carbohydrates among high alpine plant species: The sweet and low.

Rosenstiel, Todd¹, Forbis, Tara¹, Monson, Russell¹, ¹

ABSTRACT- Alpine plants are often generalized as having relatively high concentrations of total non-structural carbohydrates (TNC). To gain insight into the functional significance of these high TNC levels, we have measured the seasonal variation in carbohydrates among 12 grass and forb species occurring in fellfield communities at the Niwot Ridge LTER site in Colorado. As was reported in previous studies, the majority of TNC in alpine leaves was dominated by soluble carbohydrates. Midsummer soluble TNC values ranged from 87.6±6.24 to 622.54±9.47 mol g^-1 dwt. The greatest absolute contents of TNC were generally found in the rhizomatous forb Acomastylis rossi and the cushion plant Silene acaulis. Cyclic and/or acyclic polyols were detected in all 12 species, and represented from 0.24% to 79.31% of the soluble TNC, with 8 species containing over 30% of soluble TNC as polyols. The cyclitol myo-inositol occurred in all species and contents ranged from 1.48±0.35 to 119.86±1.52 mol g^-1 dwt, contributing up to 61.5% of the total soluble TNC in Trifolium nanum. Although all species maintained a large percentage of their total TNC in soluble forms, there were significant species-specific differences with regards to the patterns of partitioning. The concentrations and patterns of distribution of polyols, particularly cyclitols such as myo-inositol, in plants of this alpine ecosystem, further support the proposed role of these carbohydrates as compatible solutes or cryoprotectants.

KEY WORDS: Carbohydrates, Alpine, Silene acaulis, myo-inositol