Farhat Fozia, Arfan Muhammad, Wang Xiukang, Tariq Arneeb, Kamran Muhammad, Tabassum Hafiza Naila, Tariq Ifra, Mora-Poblete Freddy, Iqbal Rashid, El-Sabrout Ahmed M, Elansary Hosam O
Department of Botany, University of Agriculture (UAF), Faisalabad, Pakistan.
Shaanxi Key Laboratory of Chinese Jujube, College of Life Sciences, Yan'an University, Yan'an, China.
Front Plant Sci. 2022 Feb 18;13:850567. doi: 10.3389/fpls.2022.850567. eCollection 2022.
It has been established that wheat ( L.) has a higher Cd absorption capacity than other cereal crops causing an excess daily Cd intake and a huge threat for public health. Therefore, the reduction of Cd accumulation in wheat from the soil is a crucial food-security issue. A pot trial was performed on Cd-stressed wheat seedlings to evaluate the morphological and physio-biochemical responses foliage spray of two different bio-stimulants, i.e., ascorbic acid (AsA) and moringa leaf extract (MLE). Two wheat cultivars (Fsd-08 and Glxy-13) were exposed to cadmium (CdCl.5HO) stress (0, 500, and 1,000 μM), along with foliar spray of AsA (0 and 50 mM) and MLE (0 and 3%). The most observable growth reduction was documented in plants that are exposed to a higher Cd concentration (1,000 μM), followed by the lower Cd level (500 μM). The wheat growth attributes, such as number of leaves per plant, number of tillers per plant, biomass yield, shoot/root length, and leaf area, were greatly depressed under the Cd stress, irrespective of the cultivar. Under the increasing Cd stress, a significant diminution was observed in maximum photochemical efficiency (Fv/Fm), photochemical quenching (qP), and electron transport rate (ETR) accompanied with reduced gas exchange attributes. However, Cd-induced phytotoxicity enhanced the non-photochemical quenching (NPQ) and internal carbon dioxide concentration (Ci), which was confirmed by their significant positive correlation with Cd contents in shoot and root tissues of both cultivars. The contents of proline, AsA, glycine betaine (GB), tocopherol, total free amino acid (TFAA), and total soluble sugar (TSS) were greatly decreased with Cd stress (1,000 μM), while MLE and AsA significantly enhanced the osmolytes accumulation under both Cd levels (especially 500 μM level). The Cd accumulation was predominantly found in the root as compared to shoots in both cultivars, which has declined after the application of MLE and AsA. Conclusively, MLE was found to be more effective to mitigate Cd-induced phytotoxicity up to 500 μM Cd concentration, compared with the AsA amendment.
已经确定，小麦（L.）比其他谷类作物具有更高的镉吸收能力，导致每日镉摄入量超标，对公众健康构成巨大威胁。因此，减少土壤中小麦对镉的积累是一个至关重要的粮食安全问题。对镉胁迫下的小麦幼苗进行了盆栽试验，以评估两种不同生物刺激剂即抗坏血酸（AsA）和辣木叶提取物（MLE）叶面喷施后的形态和生理生化反应。两个小麦品种（Fsd - 08和Glxy - 13）分别暴露于镉（CdCl₂·5H₂O）胁迫（0、500和1000 μM）下，并进行AsA（0和50 mM）和MLE（0和3%）的叶面喷施。在暴露于较高镉浓度（1000 μM）的植株中记录到最明显的生长抑制，其次是较低镉水平（500 μM）。无论品种如何，镉胁迫下小麦的生长特性，如单株叶片数、单株分蘖数、生物量产量、地上部/根部长度和叶面积都受到极大抑制。在镉胁迫增加的情况下，最大光化学效率（Fv/Fm）、光化学猝灭（qP）和电子传递速率（ETR）显著降低，同时气体交换特性也降低。然而，镉诱导的植物毒性增强了非光化学猝灭（NPQ）和胞内二氧化碳浓度（Ci），这通过它们与两个品种地上部和根部组织中镉含量的显著正相关得到证实。脯氨酸、AsA、甘氨酸甜菜碱（GB）、生育酚、总游离氨基酸（TFAA）和总可溶性糖（TSS）的含量在镉胁迫（1000 μM）下大幅下降，而MLE和AsA在两种镉水平下（尤其是500 μM水平）均显著提高了渗透调节物质的积累。与施用AsA相比，两个品种的根部镉积累均明显高于地上部，施用MLE和AsA后镉积累有所下降。总之，发现在镉浓度高达500 μM时，与施用AsA相比，MLE在减轻镉诱导的植物毒性方面更有效。
