Effect of Carbon Dioxide on Nitrate Accumulation and Nitrate Reductase Induction in Corn Seedlings

Abstract

Exposure of the leaf canopy of corn seedlings (Zea mays L.) to atmospheric C02 levels ranging from 100 to 800 ,ul/l decreased nitrate accumulation and nitrate reductase activity. Plants pretreated with C02 in the dark and maintained in an atmosphere containing 100 ,ul/l C02 accumulated 7-fold more nitrate and had 2-fold more nitrate reductase activity than plants exposed to 600 ,l/l C02, after 5 hours of illumination.

Relationships between Carbon Dioxide, Malate, and Nitrate Accumulation and Reduction in Corn (Zea mays L.) Seedlings

“…Because Because nitrate is both inducer and substrate for NR,3 any factor affecting uptake and transport of nitrate would alter NRA levels and the rate of supply of reduced nitrogen to the plant (16). It In contrast, Purvis et al (22) found that the accumulation of nitrate by roots of illuminated intact corn plants was inversely related to their initial levels of malate (malate levels induced by pretreatment with K2CO3). There was no stoichiometry between NO3-accumulation and malate depletion during the uptake period.…”

“…Our data (Table I and ref. 22) indicate that no more than half of the effect can be attributed to transpiration.…”

“…Since the CO2 treatments consistently increased the malate concentration in leaf blades, it was suggested that malate was in some way inhibiting the influx of NO3- (22). Because we were unable to conceive of experimental techniques using leaf tissue, we decided to re-examine the uptake of NO3-using roots that contained high levels of malate.…”

The nitrate and ammonium nitrate supply have a major influence on the response of photosynthesis, carbon metabolism, nitrogen metabolism and growth to elevated carbon dioxide in tobacco

“…There is conflicting evidence with respect to the effect of elevated [CO 2 ] on nitrate reductase (NR) activity. Although elevated [CO 2 ] led to a small increase of NR activity in mustard (Maeskaya et al 1990) and Vigna radiata (Sharma & Sen Gupta 1990), it produced a two-fold decrease of NR activity in wheat (Hocking & Meyer 1991a), maize (Purvis, Peters & Hageman 1974), and a 15-25% decrease in Nicotiana plumbaginifolia (Ferrario-Mery et al 1997). It also led to a decrease of nitrite reductase activity in lettuce (Besford & Hand 1989).…”

“…However, in many other studies with a range of species including wheat (Hocking & Meyer 1991a;Mitchell et al 1994;McKee & Woodward 1994;Rogers et al 1996b;Fangmeier et al 1997), cotton (Wong 1979;Rogers et al 1996a), Xanthium occidentale (Hocking & Meyer 1985), Eucalyptis grandis (Conroy, Milham & Barlow 1992) (Wong 1979;Hocking & Meyer 1991a, 1991bPettersson et al 1993;Rogers et al 1993;McKee & Woodward 1994;Jacob et al 1995;Poorter et al 1997), elevated [CO 2 ] should promote more growth in nitrogen-limiting conditions. Although the increased nitrogen use efficiency in elevated [CO 2 ] is partly due to a decrease of the nitrate content (Purvis et al 1974; Yelle, Gosselin & Trudel 1987;Hocking & Meyer 1985;Hocking & Meyer 1991b;Poorter et al 1997), growth in elevated [CO 2 ] also typically leads to a lower organic nitrogen concentration (see above), indicating that organic nitrogen use efficiency is also improved (Wong 1979;Curtis et al 1989;Garbutt et al 1990;Coleman et al 1991;Hocking & Meyer 1991a, 1991bColeman & Bazzaz 1992;Gries et al 1993;Pettersson et al 1993;Pettersson & MacDonald 1994;Körner & Miglietta 1994;Ferrario-Mery et al 1997;Poorter et al 1997).In the following experiments our main aims were therefore (i) to analyse the effect of elevated [CO 2 ] on plant nitrogen status in plants growing at a range of nitrogen supplies, by mo...…”