Boominathan Rengasamy, Doran Pauline M
School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney NSW 2052, Australia.
New Phytol. 2002 Nov;156(2):205-215. doi: 10.1046/j.1469-8137.2002.00506.x.
• The aim of this study was to determine whether superior antioxidative defences contribute to Ni tolerance in roots of the hyperaccumulator species, Alyssum bertolonii . Antioxidative responses were compared in hairy roots of A. bertolonii and the nonhyperaccumulator, Nicotiana tabacum . • Growth, Ni uptake, antioxidative enzyme activities, lipid peroxidation and concentrations of H O and surface -SH groups were measured in hairy root cultures exposed to 25 ppm (426 µm) Ni. • Growth of A. bertolonii roots was not affected by Ni, whereas Ni prevented N. tabacum root growth. Endogenous activities of superoxide dismutase and catalase were 2.4 and > 500 times greater, respectively, in A. bertolonii roots than in N. tabacum . H O levels rose significantly with Ni treatment in both species, by factors of 3.6 and 8.6, respectively. • Compared with N. tabacum , oxidative damage may be minimised in A. bertolonii roots by high endogenous activities of catalase and, to a lesser extent, superoxide dismutase. As accumulation of H O was not detrimental to A. bertolonii, enhanced mechanisms for tolerating active oxygen species may also be present.
• 本研究的目的是确定超积累植物物种伯托洛地衣藻（Alyssum bertolonii）根系中卓越的抗氧化防御机制是否有助于其对镍的耐受性。对伯托洛地衣藻和非超积累植物烟草（Nicotiana tabacum）的毛状根中的抗氧化反应进行了比较。
• 在暴露于25 ppm（426 µmol）镍的毛状根培养物中，测量了生长、镍吸收、抗氧化酶活性、脂质过氧化以及过氧化氢（H₂O₂）和表面-SH基团的浓度。
• 镍对伯托洛地衣藻根系的生长没有影响，而镍抑制了烟草根系的生长。伯托洛地衣藻根系中超氧化物歧化酶和过氧化氢酶的内源活性分别比烟草高2.4倍和500倍以上。在两种植物中，镍处理均使过氧化氢水平显著升高，分别升高了3.6倍和8.6倍。
• 与烟草相比，伯托洛地衣藻根系中过氧化氢酶的高内源活性以及程度较轻的超氧化物歧化酶活性可能使氧化损伤降至最低。由于过氧化氢的积累对伯托洛地衣藻无害，可能还存在增强的活性氧耐受机制。
