Influence of additional ammonium supply on some nutritional aspects in hydroponic rose plants

Abstract

The influence of an additional supply of ammonium to a nitrate containing hydroponic solution on the mineral nutrition of greenhouse rose plants (Rosa hybrida cv. ‘Lambada’) has been investigated. The effect on NPK uptake, mineral contents in roots and leaves as well as nitrate reductase (NR) and glutamine synthetase (GS) activities were examined. The addition of ammonium in a nutrient solution containing nitrate produced a total nitrogen uptake increase during shoot elongation, while in the absence of ammonium, nitrate uptake was lower during shoot elongation. Adding ammonium to the hydroponics solution caused an increase of potassium uptake while ammonium absorption was constant. Phosphate uptake was always higher in combined nitrate plus ammonium treatment, likewise in this treatment the most relevant effect on plant mineral content was the increase of P concentration in the roots. In both treatments with or without NH+4, free nitrate was notably higher in the roots than in leaves, indicating that nitrate reduction in rose plants takes place mainly in the leaves. NR activity in the leaves was higher when ammonium was present, whereas the root GS activity was similar in both treatments. The influence of ammonium on phosphate uptake and the subsequent effects on transport of other ions and enzymatic activities are discussed.

Different availabilities of reduced nitrogen: response to oxidative stress in chicory plants

“…The following nitrate assimilation is testified by the increments of this component in the treated samples, which can be attributed to the decrease of photosynthetic organic matrix. The phosphate contents decrease and, on the other hand, the increase in the nitrate content, observed in the three tests (Table 1), might be due to a response determined by the need for an equilibrium of cellular homeostasis (Gniazdowska and Rychter, 2000;Lorenzo et al, 2000). The variations of the reduced and oxidized forms of ascorbic acid (Table 2) are in agreement with the higher involvement registered for the APX activity in comparison with the PPO activity ( Table 3).…”

Predicting In vitro Culture Medium Macro-Nutrients Composition for Pear Rootstocks Using Regression Analysis and Neural Network Models

“…High NH${}_4^{+}$ concentrations significantly diminished the mean number of shoot per explant. This may be due to the significant inhibitory effects of NH${}_4^{+}$ on other ionś uptake (Gerendás et al, 1997; Lorenzo et al, 2000). Moreover, some investigations suggested that high amounts of NH${}_4^{+}$ adversely effect on plant metabolism causing to physiological and morphological disorders.…”

Evaluation of Genotoxic Risks Due to Temporal Changes in Soil Urea: Using <i>Allium cepa</i> L. Root Tip Bioassay

“…The inhibition of primary root growth by inhibiting cell elongation and division are toxicity symptoms as reported by Qin et al (2011) in Arabidopsis. A high ratio of ammonium to nitrate enhanced the uptake of P (Lorenzo et al 2000a) and N (Lorenzo et al 2000b) during shoot elongation by rose plants. This can be explained by the preferential uptake of NH 4 as compared with NO 3 (Marschner 1995), and also by the reduction of solution pH (Feigin et al 1986).…”