Effect of magnesium‐deficiency on antioxidative systems in needles of Norway spruce [Picea abies (L.) Karst.] grown with different ratios of nitrate and ammonium as nitrogen sources

Abstract

summary The effect of magnesium deficiency and variations of the ammonium to nitrate ratio on chlorophyll, soluble protein and antioxidative systems was investigated in current year's needles of clonal spruce trees [Picea abies (L.) Karst.]. The trees were grown for 1 yr in sand culture with circulating nutrient solutions containing sufficient (0.2 mM) or limiting (0.041 mM) concentrations of Mg. The nitrogen concentration of the nutrient solutions was not varied (5 mM) but the NO3−/NH4+‐ratio was adjusted TO 0.76 in Mg‐sufficient and to 1.86, 0.76 and 0.035 in Mg‐limited plants, Under Mg‐limitation, the chlorophyll, soluble protein and Mg‐contem were lowest in needles of trees supplied with NH4+ and highest in trees supplied with NO4− as major N‐source. Apoplastic peroxidase activities were not affected by changes in nutrition. In total needle extracts, NADH oxidase, ascorbate peroxidase, mimodehydroascorbate reductase, glutatkione reductase and asoorbate content were not, or only little, affected by changes in nutrition, except for trees grown with the highest N4+‐concentrations. Glutathtone content and guaiacol peroxidase were increased in Mg‐deficient needles. Superoxide dismutase activity was decreased in Mg‐limited needles of trees grown with N4+ and increased in needles of trees grown with NO3− as a major N‐source, Except for superoxide dismutase, the activities of antioxidant enzymes and substrates were not correlated with the decree of needle chlorosis. Superoxide dismurase activity was low compared to enzymatic activities involved in H2O2 detoxification. Supposing that the needles suffered from enhanced oxidative stress, these results suggest that scavenging of O2− was a limiting factor in stress compensation rather than the detoxification of H2O2.

Suitability of the antioxidative system as marker of magnesium deficiencyin Capsicum annuum L. plants under controlled conditions

“…On the contrary, and also with P. vulgaris, Cakmak (1994) and Polle et al (1994) did not observe any significant effect of Mg deficiency on protein concentration. This lack of general agreement is probably due to differences in experimental conditions.…”

“…Similarly, an enhancement of the scavenging systems under Mg deficiency was reported in needles of Picea abies (Polle et al 1994). Furthermore, in primary leaves of P. vulgaris, Mg deficiency induced an increase in SOD, APX and GR activities (Cakmak and Marschner 1992).…”

“…Besford (1978) reported that pyruvate kinase activity in extracts from tomato leaves was correlated with Mg and K concentrations and, thus, this activity was proposed as an indicator of Mg disorder. In primary leaves of Phaseolus vulgaris (Cakmak and Marschner 1992) and in needles of Picea abies (Polle et al 1994), there is evidence that the cell plant scavenging system is enhanced by Mg deficiency. Under stress conditions, plant cells produce active oxygen species, mainly superoxide and hydrogen superoxide, that can initiate cascade reactions leading to destructive species such as lipid peroxides, among others (Noctor and Foyer 1998).…”

Overexpression of sweetpotato swpa4 peroxidase results in increased hydrogen peroxide production and enhances stress tolerance in tobacco

“…2d). In order to assess the levels of cytosolic contamination in the cell wall-bound or apoplastic washing Xuid fractions, catalase activity was analyzed in each fraction, as catalase was used as a cytosolic molecular marker for leakage from broken cells (Polle et al 1994). Catalase activity was detected in the soluble protein extracts, but not in the cell wall-bound and apoplastic Xuid fractions (data not shown).…”

Influences of magnesium deficiency and cerium on antioxidant system of spinach chloroplasts

“…Ze Á S. Yin Á Z. Ji Á L. Luo Á C. Liu Á F. Hong (&) Medical College of Soochow University, 215123 Suzhou, People's Republic of China e-mail: Hongfsh_cn@sina.com; Hongfsh@hotmail.com reduced the chl content and caused chlorosis of bean subjected to Mg deficiency, but it did not obviously influence Mg content in bean (Marschner and Cakmak 1989). By Mg deficiency, the activities of superoxide dismutase (SOD), ASA-POD, GR and the contents of antioxidants such as ASA, SH compounds were increased and ROS such as O 2 Á-and OH were accumulated in bean leaves (Cakma 1994;Cakma et al 1994;Poller et al 1994;Wang and Chu 1998).…”