Carbohydrates in Roots and Rhizomes of Perennial Grasses

Abstract

SUMMARYRoots and rhizomes were sampled in a three-year-old grass ley during one year using a mesh bag method and soil coring. Samples, collected after different growth periods (1, 2, 3, 4, 5, 6 and 12 months) and at different times of the year, were analyzed for carbohydrates and Klason lignin. Throughout the year the rhizomes contained more non-structural carbohydrates (20 to '^0% of the organic matter) than the roots (1 to 8%). The non-structural carbohydrate content varied over the year with a maximum in autumn and minimum in early spring and sunimer after the first grass cut. Fructan was the predominant constituent in this fraction. Structural carbohydrates and Klason lignin showed relatively small variations over the annual cycle. The ratio between structural carbohydrates and Klason lignin showed little variation with time but differed between roots (1-9) and rhizomes (2-5). The xylose content was higher in the roots than in the rhizomes. Only small changes occurred with time in the relative composition of the structural carbohydrates. This consistency in composition implies that there was a difference between subterranean and aerial parts. In the latter, ageing is characterized by increased lignification and systematic changes in structural carbohydrates owing to the formation of secondary cell walls.

Competition under high and low nutrient levels among three grassland species occupying different positions in a successional sequence

“…However, there is no evidence of a larger storage capacity in Festuca than in faster-growing species such as Holcus or Lolium (Atkinson & Farrar, 1983 ;Steen & Larsson, 1986 ;Kraus et al, 1994). Moreover, at the beginning of winter in the mixed treatments the total biomass of the faster-growing species was much greater, suggesting that their absolute storage capacity is greater, which would lead to superior regrowth in spring.…”

Uptake and Assimilation of NO3− and NH4+ by Nitrogen-Deficient Perennial Ryegrass Turf

“…Similarly, the content of fructans in the tissue was calculated from the increase in fructose following acid hydrolysis. In a preliminary experiment, starch was determined for both N-deficient and N-supplied tissue by the method of Steen and Larsson (27) and found to be present at very low levels. Consequently, starch was excluded from these analyses.…”

“…Soluble carbohydrates in the tissue were analyzed by a modification of the method of Steen and Larsson (27). One hundred mg of ground tissue was extracted for 45 min in 5 mL of 0.1 M ammonium acetate (pH 5.0) in a shaking waterbath at 60°C.…”

“…Nitrate and NH4I were determined both in the uptake solution and in aqueous tissue extracts by the Carlson method (6). Kjeldahl N (reduced N) was measured by a method modified to exclude NO3-from the analysis (2).Soluble carbohydrates in the tissue were analyzed by a modification of the method of Steen and Larsson (27). One hundred mg of ground tissue was extracted for 45 min in 5 mL of 0.1 M ammonium acetate (pH 5.0) in a shaking waterbath at 60°C.…”

Steady‐state nutrition and growth responses of Betula pendula to different relative supply rates of copper

“…Nitrogen was determined as NH 4 + and NO 3 -, by a micro-Kjeldahl method with a flow injection analyser (Bifok FIA 5010, Tecator, Höganäs, Sweden) with gas diffusion and phenol red as the indicator (Svensson & Anfält 1982). Carbohydrates were extracted according to Steen & Larsson (1986), slightly modified (personal communication A. Flower-Ellis). Soluble sugars were obtained first, then starch, which was analysed enzymatically and measured on a spectrophotometer (Hitachi U1100) attached to an autosampler (Hitachi AS 3000, Hitachi Ltd, Tokyo, Japan).…”