ISSN:
1573-5036
Keywords:
Amino acids
;
Festuca arundinacea
;
N fractions
;
Tall fescue
;
Tissue fractions
;
Water stress
Source:
Springer Online Journal Archives 1860-2000
Topics:
Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
Notes:
Summary Environmental and management factors can influence the protein concentration of forages, significantly altering specific amino acid content. Drought, high rates of fertilizer N and the presence of a fungal endophyte have been associated with significant alterations in plant N metabolites and animal performance problems on tall fescue. A controlled environment study was conducted to examine the influence of N fertilization (10 and 100 μgN/g) and water regime (low and adequate soil water availability) upon the distribution and concentration of amino acids in endophyte infected tall fescue (Festuca arundinacea, Schreb.) herbage. Tall fescue tissue was collected from three replicates of each treatment, quick frozen in liquid N and lyophilized. Two insoluble (RI, structural residue; RII, membrane residue) and two soluble (SI, soluble protein; SII, low molecular weight N compounds) fractions were collected. Amino acid analyses of acid hydrolysates of fractions showed that application of 100 N significantly increased the concentration (per unit dry weight) of all amino acids in the entire plant, with an average increase of about 55%. Application of 110 N increased the concentrations of most amino acids in fractions RI, RII, and SI, but only aspartate-asparagine, glutamate-glutamine, alanine, threonine, serine, valine and proline in fraction SII. Fraction RI contained about 65% of total amino acids under 10 N and 55% under 110 N even though N level did not alter dry matter distribution among fractions. While the amount of dry matter was least in SI, amino acids in the fraction ranged from 8% (leucine, 10 N) to 20% (lysine, 110 N) of the total amount of specific amino acids recovered. Significant increases in proline, glutamate, aspartate, serine, valine, threonine, alanine and phenylalanine concentration occurred under low soil-water availability compared with adequate water conditions. Basic amino acids including histidine, arginine and lysine increased with increased N and with water stress at each N level. Application of N increased amounts, and water stress influenced distribution of amino acids among the fractions of tall fescue herhage. Nitrogenous components, such as non-protein amino acids which could influence plant nutritive quality, were increased in fraction SII by increased N and water stress.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02197159
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