Khan M Iqbal R, Khan Nafees A
Plant Physiology and Biochemistry Section, Department of Botany, Aligarh Muslim University, Aligarh, 202 002, India.
Protoplasma. 2014 Sep;251(5):1007-19. doi: 10.1007/s00709-014-0610-7. Epub 2014 Jan 30.
We investigated the influence of exogenously sourced ethylene (200 μL L(-1) ethephon) in the protection of photosynthesis against 200 mg kg(-1) soil each of nickel (Ni)- and zinc (Zn)-accrued stress in mustard (Brassica juncea L.). Plants grown with Ni or Zn but without ethephon exhibited increased activity of 1-aminocyclopropane carboxylic acid synthase, and ethylene with increased oxidative stress measured as H2O2 content and lipid peroxidation compared with control plants. The oxidative stress in Ni-grown plants was higher than Zn-grown plants. Under metal stress, ethylene protected photosynthetic potential by efficient PS II activity and through increased activity of ribulose-1,5-bisphosphate carboxylase and photosynthetic nitrogen use efficiency (P-NUE). Application of 200 μL L(-1) ethephon to Ni- or Zn-grown plants significantly alleviated toxicity and reduced the oxidative stress to a greater extent together with the improved net photosynthesis due to induced activity of ascorbate peroxidase and glutathione (GSH) reductase, resulting in increased production of reduced GSH. Ethylene formation resulting from ethephon application alleviated Ni and Zn stress by reducing oxidative stress caused by stress ethylene production and maintained increased GSH pool. The involvement of ethylene in reversal of photosynthetic inhibition by Ni and Zn stress was related to the changes in PS II activity, P-NUE, and antioxidant capacity was confirmed using ethylene action inhibitor, norbornadiene.
我们研究了外源乙烯（200 μL L⁻¹ 乙烯利）对芥菜（Brassica juncea L.）光合作用的保护作用，以抵御土壤中分别添加200 mg kg⁻¹ 的镍（Ni）和锌（Zn）所产生的胁迫。与对照植株相比，在添加Ni或Zn但未添加乙烯利的条件下生长的植株，1-氨基环丙烷羧酸合酶的活性增加，且以H₂O₂ 含量和脂质过氧化作用衡量的氧化胁迫随乙烯含量增加。镍处理植株中的氧化胁迫高于锌处理植株。在金属胁迫下，乙烯通过高效的PS II活性以及增加1,5-二磷酸核酮糖羧化酶的活性和光合氮利用效率（P-NUE）来保护光合潜力。向镍或锌处理的植株施用200 μL L⁻¹ 乙烯利可显著减轻毒性，并在更大程度上降低氧化胁迫，同时由于抗坏血酸过氧化物酶和谷胱甘肽（GSH）还原酶的诱导活性提高了净光合作用，从而导致还原型GSH产量增加。乙烯利施用产生的乙烯形成通过减少胁迫乙烯产生引起的氧化胁迫来减轻镍和锌胁迫，并维持GSH库的增加。使用乙烯作用抑制剂降冰片二烯证实，乙烯参与逆转镍和锌胁迫对光合作用的抑制作用与PS II活性、P-NUE和抗氧化能力的变化有关。
