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首页> 外文期刊>Biology Bulletin >Resistance of Surface Phosphohydrolases of Barley Root Cells to Nickel Salts Is One of Factors of Plant Adaptation to Excessive Nickel in the Environment
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Resistance of Surface Phosphohydrolases of Barley Root Cells to Nickel Salts Is One of Factors of Plant Adaptation to Excessive Nickel in the Environment

机译：大麦根细胞表面磷酸化酶对镍盐​​的抗性是植物适应环境中过量镍的因素之一。

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摘要

We studied the effect of nickel ions on the activity of ecto-phosphohydrolases (acid phosphatase and Ca-stimulated nucleotidase) from root surface of etiolated barley seedlings as well as from root microsomal fraction. The presence of nickel nitrate (25 μM) proved to stop root growth and insignificantly (on average by 20%) decreased specific hydrolytic activity of both enzymes determined on root surface as well as in the root microsomal fraction. At the same time, direct addition of nickel to the incubation mixture when measuring the substrate hydrolysis demonstrated high resistance of the microsomal fraction enzymes to the salts. A significant decrease in Ca-stimulated nucleotidase activity was observed only for nickel nitrate concentrations above 100 μM, reaching 50-60% for 3 mM Ni(NO_3)_2. The presence of an activator ion as well as extended duration of the microsomal fraction pretreatment with nickel nitrate (2.5 h) did not increase its effect on the enzyme activity. The pattern of nickel effect on acid phosphatase activity depended on the presence of magnesium ions in the mixture but did not change after extended duration of the microsomal fraction pretreatment (3 h). Inhibition of acid phosphatase activity in the presence of magnesium was observed only for nickel nitrate concentrations above 500 μM being no more than 20% for 3 mM Ni(NO_3)_2. Hence, the hydrolytic enzymes of the apoplast of plant root cells have different tolerance to nickel salts. We propose that an insignificant decrease in specific activity of surface nydrolases of plant roots grown on a medium containing nickel salts in concentrations inhibiting growth processes (25 μM) is not related to direct effect of Ni on the apoplastic enzymes. The significance of hydrolytic enzyme resistance in plant adaptation to high nickel content in the soil is discussed.
机译：我们研究了镍离子对黄化大麦幼苗根表面以及根系微粒部分外切磷酸水解酶（酸性磷酸酶和钙刺激的核苷酸酶）活性的影响。硝酸镍（25μM）的存在证明可以阻止根生长，并且在根表面和根微粒体级分中测定的两种酶的比水解活性均微不足道（平均降低20％）。同时，在测量底物水解时，将镍直接添加到培养混合物中，证明了微粒体级分酶对盐类的高抗性。仅当硝酸镍浓度高于100μM时，才观察到Ca刺激的核苷酸酶活性显着下降，对于3 mM Ni（NO_3）_2，其达到50-60％。活化剂离子的存在以及用硝酸镍预处理的微粒体级分的延长时间（2.5小时）并没有增加其对酶活性的影响。镍对酸性磷酸酶活性的影响方式取决于混合物中镁离子的存在，但在微粒体级分预处理（3小时）的延长时间后不会改变。仅在浓度大于500μM的硝酸镍对3 mM Ni（NO_3）_2不超过20％的情况下，观察到在镁存在下酸性磷酸酶活性的抑制作用。因此，植物根细胞的质外体的水解酶对镍盐具有不同的耐受性。我们提出，在含镍盐的培养基上生长浓度（25μM）抑制生长的植物根部表面根瘤菌比活性的显着降低与Ni对质外生酶的直接影响无关。讨论了耐水解酶对植物适应土壤中高镍含量的重要意义。

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  • 来源
    《Biology Bulletin》 |2004年第6期|p.591-597|共7页
  • 作者

    M. D. Fedorovskaya;

  • 作者单位

    Timiryazev Institute of Plant Physiology, Russian Academy of Science, Botanicheskaya ul. 35, Moscow, 127276 Russia;

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  • 正文语种 eng
  • 中图分类 生物科学;
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