Kanu Adam Sheka, Ashraf Umair, Mansaray Lamin R, Abbas Farhat, Fiaz Sajid, Amanullah Sikandar, Charley Christen Shaka, Tang Xiangru
Department of Crop Science and Technology, College of Agriculture, South China Agricultural University, Guangzhou, China.
Sierra Leone Agricultural Research Institute (SLARI)-Rokupr Agricultural Research Centre (RARC), Freetown, Sierra Leone.
Front Plant Sci. 2022 Apr 25;13:849477. doi: 10.3389/fpls.2022.849477. eCollection 2022.
Cadmium (Cd) has detrimental effects on crop plants, whereas, jasmonates (JAs) play a vital role in abiotic stress tolerance in plants. The present study investigated the effects of exogenous application of methyl jasmonate (MeJa) on the physio-biochemical attributes, yield, and quality of two fragrant rice cultivars, i.e., Xiangyaxiangzhan and Meixiangzhan-2 under Cd stress. The experiment was comprised of four treatments, i.e., CK, control (normal conditions); Cd: 100 mg Cd kg of soil; MeJa: exogenous application of MeJa at 20 mM; and Cd + MeJa: 100 mg Cd kg of soil + exogenous MeJa application at 20 mM. Results depicted that Cd toxicity resulted in a substantial reduction of enzymatic activities and non-enzymatic antioxidants, chlorophyll contents, while enhanced oxidative damage in the terms of lipid peroxidation (higher malondialdehyde (MDA) contents), HO, and electrolyte leakage. Proline contents were found higher whereas protein and soluble sugars were lower under Cd stress as compared with Ck and Cd + MeJa. Exogenous MeJa application further improved the panicles per pot, spikelets per panicle, seed setting (%), 1,000 grain weight, and yield per pot under Cd stress conditions as compared with non-MeJa applied plant under Cd stress. In addition, exogenous MeJa application enhanced the accumulation of macro (N, P, K, Mg, and Ca) and micronutrients (Mn, Zn, Fe, and Cr) in both cultivars under Cd stress, while reduced the Cd contents in different plant parts. Overall, the contents of Cd in different plant organs were recorded as: root > stem > leaves > grains for all treatments. Comparing both cultivars, the grain Cd contents were higher in Meixiangzhan 2 than Xiangyaxianzhan under Cd contaminated conditions. Conclusively, Cd toxicity impaired growth in rice by affecting physio-biochemical attributes, however, Xiangyaxiangzhan performed better than Meixiangzhan-2 cultivar.
镉（Cd）对农作物具有有害影响，而茉莉酸（JAs）在植物对非生物胁迫的耐受性中起着至关重要的作用。本研究调查了在镉胁迫下，外源施加茉莉酸甲酯（MeJa）对两个香稻品种象牙香占和美香占2号的生理生化特性、产量和品质的影响。试验包括四个处理，即CK，对照（正常条件）；Cd：100 mg Cd/kg土壤；MeJa：外源施加20 mM的MeJa；以及Cd + MeJa：100 mg Cd/kg土壤+外源施加20 mM的MeJa。结果表明，镉毒性导致酶活性和非酶抗氧化剂、叶绿素含量大幅降低，而在脂质过氧化（较高的丙二醛（MDA）含量）、过氧化氢（HO）和电解质渗漏方面，氧化损伤加剧。与CK和Cd + MeJa相比，镉胁迫下脯氨酸含量较高，而蛋白质和可溶性糖含量较低。与镉胁迫下未施加MeJa的植株相比，外源施加MeJa进一步提高了镉胁迫条件下每盆的穗数、每穗颖花数、结实率（%）、千粒重和每盆产量。此外，外源施加MeJa增强了镉胁迫下两个品种中大量元素（氮、磷、钾、镁和钙）和微量元素（锰、锌、铁和铬）的积累，同时降低了不同植物部位的镉含量。总体而言，所有处理下不同植物器官中的镉含量记录为：根＞茎＞叶＞籽粒。比较两个品种，在镉污染条件下，美香占2号的籽粒镉含量高于象牙香占。总之，镉毒性通过影响生理生化特性损害了水稻生长，然而，象牙香占的表现优于美香占2号品种。
