Results on the content of the major inorganic anions and cations (Cl-, NO3-, H2PO4-, SO42-, Na+, K+, Mg2+ and Ca2+) in heads of hydroponically grown endive with two levels of N (8 and 16 mM) supplied in mixed form (NH4+:NO3- 50:50) or as nitrate (0:100) are reported. The trial was performed over a 48 day period starting from the transfer of plants into nutritive solution treatments. Six samples were taken: the first five samples at one week intervals from transfer and the last after two more weeks. The ratio between the nitrogen forms distinctly affected the plant release of H+ or OH-/HCO3- ions into the nutritive medium. The release of H+, typical of ammonium nutrition, reached on average 16.4 meq-plant-1 with the 50:50 NH4+:NO3- ratio; NO3--fed plants released 16.3 meq·plant-1 of OH-/HCO3-. After 28 and 34 days from the beginning of treatments the total ions concentration was not affected by N level, but only by the ratio between its chemical forms. In these two samples, cations reached on average 229 and 241 meq·100 g-1 dry matter, respectively, with N in mixed form and 202 and 219 meq·100 g-1 dry matter with 100% NO3--N. This difference was even greater for total inorganic anions 34 days after the beginning of treatment, i.e. 247 vs 199 meq·100 g-1 dry matter K+ and CI- concentrations were particularly high with an NH4+:NO3- ratio 50:50. K+ ion could be related to the good capability of endive to assimilate NH4+-N; Cl- could have replaced NO3- in its osmoregulatory functions.
Effects of two N levels and two NH4+:NO3- ratios on endive (Cichorium endivia L. var. crispum Hegi). II. Accumulation of the major inorganic ions
SANTAMARIA, Pietro;
1997-01-01
Abstract
Results on the content of the major inorganic anions and cations (Cl-, NO3-, H2PO4-, SO42-, Na+, K+, Mg2+ and Ca2+) in heads of hydroponically grown endive with two levels of N (8 and 16 mM) supplied in mixed form (NH4+:NO3- 50:50) or as nitrate (0:100) are reported. The trial was performed over a 48 day period starting from the transfer of plants into nutritive solution treatments. Six samples were taken: the first five samples at one week intervals from transfer and the last after two more weeks. The ratio between the nitrogen forms distinctly affected the plant release of H+ or OH-/HCO3- ions into the nutritive medium. The release of H+, typical of ammonium nutrition, reached on average 16.4 meq-plant-1 with the 50:50 NH4+:NO3- ratio; NO3--fed plants released 16.3 meq·plant-1 of OH-/HCO3-. After 28 and 34 days from the beginning of treatments the total ions concentration was not affected by N level, but only by the ratio between its chemical forms. In these two samples, cations reached on average 229 and 241 meq·100 g-1 dry matter, respectively, with N in mixed form and 202 and 219 meq·100 g-1 dry matter with 100% NO3--N. This difference was even greater for total inorganic anions 34 days after the beginning of treatment, i.e. 247 vs 199 meq·100 g-1 dry matter K+ and CI- concentrations were particularly high with an NH4+:NO3- ratio 50:50. K+ ion could be related to the good capability of endive to assimilate NH4+-N; Cl- could have replaced NO3- in its osmoregulatory functions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
