Moravcová Šárka, Tůma Jiří, Dučaiová Zuzana Kovalíková, Waligórski Piotr, Kula Monika, Saja Diana, Słomka Aneta, Bąba Wojciech, Libik-Konieczny Marta
Department of Biology, Faculty of Science, University of Hradec Kralove, Hradecka 1285, 500 03 Hradec Kralove, Czech Republic.
Department of Biology, Faculty of Science, University of Hradec Kralove, Hradecka 1285, 500 03 Hradec Kralove, Czech Republic.
Plant Physiol Biochem. 2018 Jan;122:19-30. doi: 10.1016/j.plaphy.2017.11.007. Epub 2017 Nov 14.
The study was focused on the influence of salicylic acid (SA) on maize seeds germination and on some physiological and biochemical processes in maize plants growing in the hydroponic culture under copper (Cu) stress. A significant influence of SA pretreatment on the advanced induction of the maize seeds metabolic activity and the level of the endogenous SA in germinated seeds and developing roots have been stated. Although, the ability of maize seeds to uptake SA and accumulate it in the germinated roots was confirmed, the growth inhibition of Cu-stressed maize seedlings was not ameliorated by SA seeds pretreatment. Cu-stressed plants exhibited a decrease in the photosynthetic pigment concentration and the increase in non-photochemical quenching (NPQ) - an indicator of an excess energy in PSII antenna assemblies lost as a heat. The amelioration effect of SA application was found only for carotenoids content which increased in stressed plants. It was also shown that maize roots growing in stress conditions significantly differed in the chemical composition in comparison to the roots of control plants, but the SA pretreatment did not affect these differences. On the other hand, it was found that SA seed pretreatment significantly influenced the ability of stressed plants to accumulate copper in the roots. It was stated that a higher level of exogenous SA application led to a lower accumulation of Cu ions in maize roots. Cu-stressed plants exhibited higher oxidative stress in roots than in leaves which was manifested as an increase in the concentration of hydrogen peroxide due to stress factor application. We observed an increase in catalase (CAT) activity in leaves of Cu-stressed plants which corresponded with a lower HO content when compared with roots where the hydrogen peroxide level was higher, and the inhibition of the CAT activity was found. Furthermore, we found that the SA seed pretreatment led to a decrease in the HO content in the roots of the Cu-stressed plants, but it did not influence the HO level in leaves. The increase in hydrogen peroxide content in the roots of Cu-stressed plants correlated with a higher activity of the MnSODI and MnSODII isoforms. It was found that SA pretreatment caused a decrease in MnSODII activity accompanied by the decrease in HO concentration. Achieved results indicated also that the changes in the chemical composition of the root tissue under copper stress constituted protection mechanisms of blocking copper flow into other plant organs. However, it might be assumed that the root tissue remodelling under Cu stress did not only prevent against the Cu ions uptake but also limited the absorption of minerals required for the normal growth leading to the inhibition of the plant development.
该研究聚焦于水杨酸（SA）对玉米种子萌发以及水培条件下铜（Cu）胁迫的玉米植株某些生理生化过程的影响。已表明SA预处理对玉米种子代谢活性的提前诱导以及发芽种子和发育中根内源性SA水平有显著影响。尽管证实了玉米种子吸收SA并在发芽根中积累SA的能力，但SA种子预处理并未改善Cu胁迫玉米幼苗的生长抑制情况。Cu胁迫植株光合色素浓度降低，非光化学猝灭（NPQ）增加——NPQ是PSII天线组件中以热形式损失的过剩能量的指标。仅发现SA处理对胁迫植株中增加的类胡萝卜素含量有改善作用。还表明，与对照植株的根相比，胁迫条件下生长的玉米根在化学成分上有显著差异，但SA预处理并未影响这些差异。另一方面，发现SA种子预处理显著影响胁迫植株在根中积累铜的能力。据指出，较高水平的外源SA施用导致玉米根中Cu离子积累减少。Cu胁迫植株根中的氧化应激高于叶片，这表现为由于胁迫因素的施加而过氧化氢浓度增加。我们观察到Cu胁迫植株叶片中过氧化氢酶（CAT）活性增加，与过氧化氢水平较高的根相比，叶片中过氧化氢含量较低，且发现CAT活性受到抑制。此外，我们发现SA种子预处理导致Cu胁迫植株根中过氧化氢含量降低，但不影响叶片中过氧化氢水平。Cu胁迫植株根中过氧化氢含量的增加与MnSODI和MnSODII同工型的较高活性相关。发现SA预处理导致MnSODII活性降低，同时过氧化氢浓度降低。所取得的结果还表明，铜胁迫下根组织化学成分的变化构成了阻止铜流入其他植物器官的保护机制。然而，可以推测，Cu胁迫下根组织的重塑不仅防止了Cu离子的吸收，还限制了正常生长所需矿物质的吸收，导致植物发育受到抑制。
