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
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
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DOI：
10.1111/j.1469-8137.1994.tb04026.x
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发表时间：
1994-12
期刊：
影响因子：
9.4
通讯作者：
A. Polle;T. Otter;B. Mehne-Jakobs
中科院分区：
文献类型：
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作者：
A. Polle;T. Otter;B. Mehne-Jakobs
研究了缺镁和氨氮比变化对当年无性系云杉[Picea abies(L.)岩溶]。这些树在沙培中生长了一年，其中循环营养液含有充足(0.2mM)或有限(0.041 mM)的镁。营养液的氮浓度不变(5 Mm)，但在镁充足的情况下，NO3-−/NH4+-比值调整为0.76，而缺镁的植株为1.86、0.76和0.035。在镁限制下，供应NH4+的树叶的叶绿素、可溶性蛋白和镁含量最低，而以NO4-−为主要氮源的树叶的叶绿素、可溶性蛋白质和镁含量最高。质外体过氧化物酶活性不受营养变化的影响。在针叶总浸出物中，NADH氧化酶、抗坏血酸过氧化物酶、亚甲基脱氢抗坏血酸还原酶、谷氨酰基还原酶和抗坏血酸含量不受营养变化的影响，或仅受营养变化的影响，但生长在最高N4+浓度的树木中，NADH氧化酶、抗坏血酸过氧化物酶、模拟脱氢抗坏血酸还原酶、谷氨酰基还原酶和抗坏血酸含量几乎不受营养变化的影响。缺镁针叶中谷胱甘肽含量和愈创木酚过氧化物酶活性增加。以N3-−为主要氮源的针叶超氧化物歧化酶活性，除超氧化物歧化酶活性外，与针叶黄化的发生程度无关。与参与H_2O_2解毒的酶活性相比，超氧化物歧化酶活性较低。假设针叶遭受了增强的氧化应激，这些结果表明，清除O2−是应激补偿的限制因素，而不是H2O2的解毒。
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.