Abstract：
CONCLUSIONS: Silicon application mitigates phosphate deficiency in barley through an interplay with auxin and nitric oxide, enhancing growth, photosynthesis, and redox balance, highlighting the potential of silicon as a fertilizer for overcoming nutritional stresses. Silicon (Si) is reported to attenuate nutritional stresses in plants, but studies on the effect of Si application to plants grown under phosphate (Pi) deficiency are still very scarce, especially in barley. Therefore, the present work was undertaken to investigate the potential role of Si in mitigating the adverse impacts of Pi deficiency in barley Hordeum vulgare L. (var. BH902). Further, the involvement of two key regulatory signaling molecules--auxin and nitric oxide (NO)--in Si-induced tolerance against Pi deficiency in barley was tested. Morphological attributes, photosynthetic parameters, oxidative stress markers (O2·-, H2O2, and MDA), antioxidant system (enzymatic--APX, CAT, SOD, GR, DHAR, MDHAR as well as non-enzymatic--AsA and GSH), NO content, and proline metabolism were the key traits that were assessed under different treatments. The P deficiency distinctly declined growth of barley seedlings, which was due to enhancement in oxidative stress leading to inhibition of photosynthesis. These results were also in parallel with an enhancement in antioxidant activity, particularly SOD and CAT, and endogenous proline level and its biosynthetic enzyme (P5CS). The addition of Si exhibited beneficial effects on barley plants grown in Pi-deficient medium as reflected in increased growth, photosynthetic activity, and redox balance through the regulation of antioxidant machinery particularly ascorbate-glutathione cycle. We noticed that auxin and NO were also found to be independently participating in Si-mediated improvement of growth and other parameters in barley roots under Pi deficiency. Data of gene expression analysis for PHOSPHATE TRANSPORTER1 (HvPHT1) indicate that Si helps in increasing Pi uptake as per the need of Pi-deficient barley seedlings, and also auxin and NO both appear to help Si in accomplishing this task probably by inducing lateral root formation. These results are suggestive of possible application of Si as a fertilizer to correct the negative effects of nutritional stresses in plants. Further research at genetic level to understand Si-induced mechanisms for mitigating Pi deficiency can be helpful in the development of new varieties with improved tolerance against Pi deficiency, especially for cultivation in areas with Pi-deficient soils.
摘要：
结论：硅的应用通过与生长素和一氧化氮的相互作用，减轻了大麦的磷酸盐缺乏，促进增长，光合作用,和氧化还原平衡，强调硅作为克服营养压力的肥料的潜力。据报道，硅（Si）可以减轻植物的营养胁迫，但是关于Si对磷酸盐（Pi）缺乏下生长的植物的影响的研究仍然很少，尤其是大麦.因此,目前的工作是研究Si在减轻大麦大麦中Pi缺乏症的不利影响中的潜在作用（var。BH902).Further,测试了两个关键调节信号分子-生长素和一氧化氮（NO）-在Si诱导的大麦对Pi缺乏症的耐受性中的参与。形态学属性,光合参数，氧化应激标志物(O2·-，H2O2和MDA)，抗氧化系统(酶--APX，CAT,SOD,GR,DHAR,MDHAR以及非酶-AsA和GSH)，无含量,和脯氨酸代谢是在不同处理下评估的关键性状。缺磷明显下降了大麦幼苗的生长，这是由于氧化应激的增强导致光合作用的抑制。这些结果也与抗氧化活性的增强平行，特别是SOD和CAT，和内源性脯氨酸水平及其生物合成酶(P5CS)。Si的添加对在Pi缺乏的培养基中生长的大麦植物表现出有益的影响，反映在增加的生长中。光合活性，和氧化还原平衡通过调节抗氧化机制，特别是抗坏血酸-谷胱甘肽循环。我们注意到，在Pi缺乏的情况下，生长素和NO也独立参与了Si介导的大麦根生长和其他参数的改善。磷酸盐转运蛋白1（HvPHT1）的基因表达分析数据表明，Si有助于根据缺乏Pi的大麦幼苗的需要增加Pi的吸收，以及生长素和NO似乎都可能通过诱导侧根形成来帮助Si完成此任务。这些结果暗示可能将Si用作肥料以纠正植物中营养胁迫的负面影响。在遗传水平上进行进一步的研究以了解Si诱导的减轻Pi缺乏症的机制可能有助于开发具有改善的抗Pi缺乏症耐受性的新品种。特别是在Pi缺乏土壤的地区种植。
