Impact of low pH and aluminium on nitrogen uptake and metabolism in roots of Lotus japonicus

Abstract

The effect of low pH and aluminum on nitrogen uptake and metabolism was studied in roots of Lotus japonicus grown in hydroponic cultures. The low pH slightly suppressed root elongation, and this effect was accompanied by the suppression of nitrate and ammonia uptake, as well as the nitrate reductase activity. In spite of high resistance of young Lotus plants to short-term Al application, the one-day treatment of Al strongly reduced nitrate uptake and also the activity of nitrate reductase (NRA) in the apical parts of roots. The glutamine synthetase activity was also suppressed by Al treatment, but in lower extent. On the other hand, the ammonium uptake and nitrite reductase activity stayed unchanged by Al treatment and the values were practically the same as in control plants. These results support the view that nitrate uptake and nitrate reduction might be the main processes responsible for Al induced growth retardation in Lotus plants grown in mineral acid soils.

Local Scale Edaphic Surveys in and out of a <i>Pericopsis elata</i> (Harms) Meeuwen Natural Forest Stand in East Cameroon

“…The supply of Nitrogen has been reported to exert strong control over the composition, diversity and productivity of many ecosystems [43]. This is because nitrogen metabolism is one of the most important factors often limiting plant growth in natural ecosystems [44]. Nitrogen-fixing trees such as P. elata have tree sources of inorganic N (nitrate, ammonium and atmospheric nitrogen) fixed by symbiotic bacteria, even though we did not determine nitrogen in this study.…”

Growth and functional responses of different cultivars of Lotus corniculatus to aluminum and low pH stress

“…However, as the soil becomes more acidic, Al is solubilized and toxic Al species (especially Al 3+ form) are released into solution (Matsumoto, 2000). Phytotoxicity of Al is characterized by rapid inhibition of root elongation (Sivaguru and Horst, 1998) and subsequent decrease of nutrient uptake (Baligar et al, 2001;Cakkmak and Horst, 1991;Cabraia et al, 1989;Mariano and Keltjens, 2005;Mistrík et al, 2000;Pal'ove-Balang and Mistrík, 2007), modification of structure and function of plasma membranes (Ikegawa et al, 2000), interference with a number of metabolic pathways, etc. (Mossor-Pietraszewska, 2001).…”

Impact of Aluminum on Phosphate Uptake and Acid Phosphatase Activity in Root Tips ofLotus Japonicus

“…The relative tolerance of Lotus japonicus to short-term Al stress was previously documented in hydroponic cultures (Pal'ove-Balang and Mistrík, 2007). Due to the fact that more than 1 mM Al was required for 50% inhibitions of root elongation during five-day treatment in the present paper we increased Al concentration to the level which completely stops elongation of roots.…”