Dry matter content as a measure of dry matter concentration in plants and their parts

This study compared the predictive ability of dry matter content (DMC, dry mass per fresh mass) of leaves, stems, roots and entire plants in relation to dry matter concentration (D, dry mass per volume of plant organ). Data came from 28 species of field-collected plants (woody and herbaceous) and 17 species of herbaceous plants grown in hydroponic sand culture. Specific leaf areas were also measured. Dry matter content of the herbaceous plants grown in sand culture varied more between tissue types than did dry matter concentration but the correlation among plant parts was stronger when using DMC. Means and standard errors for DMC (g g(-1)) were 0.212 +/- 0.009 (leaves), 0.176 +/- 0.012 (support tissues) and 0.170 +/- 0.021 (roots); for D (g cm(-3)) the values were 0.158 +/- 0.010 (leaves), 0.168 +/- 0.017 (support tissues) and 0.153 +/- 0.013 (roots). Leaf DMC provided approximate estimates of leaf D (r = 0.76) for the field-collected plants but sclerophyllous leaves from shrubs restricted to acidic bogs proved to be outliers. The relationship between these two variables was stronger in the herbaceous species grown in sand culture, especially so for whole plant estimates (r = 0.91). Dry matter content and dry matter concentration were equally good predictors of specific leaf area.