TY  - EJOU
AU  - E, Sánchez  
AU  - Ávila-Quezada, G  
AU  - Gardea, AA  
AU  - Ruiz, JM  
AU  - Romero, L  

TI  - Biosynthesis of proline in fruits of green bean plants: deficiency <i>versus</i> toxicity of nitrogen
T2  - Phyton-International Journal of Experimental Botany

PY  - 2007
VL  - 76
IS  - all
SN  - 1851-5657

AB  - The objective of this work was to determine the effect of deficiency versus toxicity of N on biosynthesis of proline in fruits of green bean plants (<i>Phaseolus vulgaris</i> L. cv. Strike). Nitrogen was applied to the nutritive solution in the form of NH<sub>4</sub>NO<sub>3</sub> at 1.5 mM (N1), 3.0 mM (N2), 6.0 mM (N3, optimal level), 12.0 mM (N4), 18.0 mM (N5), and 24.0 mM (N6). Nitrogen deficiency (N1 and N2) was characterized by having lower proline accumulation in pods and seeds, mainly because proline degradation was stimulated by the enzyme proline dehydrogenase. On the other hand, N toxicity (N4, N5, and N6) was characterized for accumulation of greater amounts of proline in pods and seeds due primarily to the greater activity of the enzyme ornitine-δ-aminotransferase. These results suggest a predominance of the ornithine over the glutamine pathway. Under our experimental conditions, proline can be defined as a good bioindicator of N excess in green bean plants. The accumulation of proline in both organs (pods and seeds) is also considered a good bioindicator of N toxicity in the study plant species.
KW  - <i>Phaseolus vulgaris</i> L.
KW  -  proline metabolism
KW  -  green bean
KW  -  nitrogen
KW  -  deficiency
KW  -  toxicity

DO  - 10.32604/phyton.2007.76.143