Physiological aspects of the ecology of Dicranum fuscescens in the subarctic. II. Seasonal patterns of organic nutrient content

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Abstract
Individual plants of C. fuscescens were collected from 2 field sites (a highland semitundra and a lowland lichen woodland) near Schefferville, Quebeck (latitude 55.degree. N) [Canada], for 4 1/2 mo. during 1974. Collections were made at 2 wk interval from June until the 2nd wk in Oct. Samples were separated into green and brown shoot components and oven-dried. Subsequently analyses were carried out to determine concentrations of total carbohydrates (sugar and starch) and lipids in the respective tissues. Total carbohydrates were found to increase in the green tissues towards the end of the season reaching a maximum of between 10 and 10.5% ash-free tissue dry weight in Oct. Lipid concentrations showed a maximum of between 3.6 and 4.0% ash-free dry weight during July and subsequently declined, in the same tissues. Seasonal trends of nutrient concentration in the brown portions of the shoot were not marked. An investigation of biomass distribution in complete plants D. fuscescens revealed that brown shoots accounted for more than half of the total. Mean lengths of these parts of the shoot were about twice those of the upper stem.