Influence of the nitrogen source and concentration on N fractions and free amino acid levels of grape vine explants

Abstract

The influence of the source of inorganic nitrogen (KNO3, ( N H 4 ) 2 S O 4 and NH4NO3) and its concentration (5, 10, 20 and 30 mM N) on total N incorporation, as well as on N distribution into different fractions (ammoniacal, amino, amide and protein) and on free amino acid levels has been determined in grape vine explants cultured in vitro.Increasing concentrations of the nitrogen source resulted in increased total N content in tissues. This effect was small for KNO3, higher for (NH4)2SO 4 and maximal for NHaNO 3. In addition, nitrate promoted an increase in amino-N only, whereas ammonium increased both the ammoniacal-N and the amino-N fractions. Incorporation of N into amide-N and protein-N were not affected significantly by the N sources tested.The application of increasing quantities of N enhanced the accumulation of most free amino acids, especially arginine, alanine and proline, but to different extents, depending on both the N source and its concentration. The combination of ammonium and nitrate resulted in a higher accumulation of amino acids than that observed with either one of the two forms alone.

Effects of the Nitrogen Source and Concentration on N Fractions in Olive Seedlings

“…The increase was moderate for KNO" more marked for (NH,)2S0" and maximal for NH,NO,. These data are in agreement, in general, witb previous results in grape vine explants (Troncoso et al, 1990;Villegas et al, 1992;Sarmiento et al, 1992).…”

“…The nitrogen nutrition of explants of grape vine roolslocks (Stewart and Rhodes, 1977;SarmIento et al, 1992) has revealed differential effects on shoot and callus development. Increasing ammonium resulted in a significanl increase in number, size and N contenl of ShOOIS, and decreased callus formalion.…”

Effect of the Form and Concentration of N on the Growth and Mineral Composition of Olive Seedlings

“…The N levels and increases, were lowest for KN03 and highest for ammonium applications, especially for NH4N03 at 10 and 20 mM of N. These results were in agreement with Hagin et al's. review (1990) and with data obtained by Troncoso et al (1990) and Sarmiento et al (1992) from grape vine explants, and were probably related to the high energy requirement for reduction by nitrate reductase and subsequent assimilation of N-N03 (Stewart and Rhodes, 1977;Campbell, 1988). K contents were al so affected by the treatments.…”

“…Nutritional factors, especiaHy nitrogen, have considerable influence on the growth of young olive plant in greenhouse conditions (Bartolini et al, 1984;Troncoso et al, 1986). Nitrogen also has a considerable influence on the growth of in vitra plant material (Hagin et al, 1990;Troncoso et al, 1990 andSarmiento et al, 1992), however there are no references to olive plant in this culture system.…”

Characterization of the largest relic Eurasian wild grapevine reservoir in Southern Iberian Peninsula

“…In total, 10.55 After disinfection, the explants were placed individually in sterile test tubes (25 × 150 mm) with 8 mL of "VID" medium (Sarimento et al, 1992) with 0.13 µmol/L indolebutyric acid (IBA) and 0.32 µmol/L benzylaminopurine (BA) with 0.6% agar, pH 5.7. Each tube was covered with a plastic cap, sealed with parafilm and placed in a growth chamber at 23±2ºC, 30 µmol/m 2 ·s of light intensity and 16 h of photoperiod.…”