Nanomaterials possessing enzyme-like activities have shown immense potential to improve plants' performance under unfavorable conditions such as abiotic stresses. Although several strategies for evaluating nano–bio interactions have been evidenced to enhance the productivity of crop/fruit-based plant species, no such attempts have been made on agroforestry trees. Herein, an abiotic stress management approach using iron oxide nanoparticles (IONPs) is demonstrated for the first time in Eucalyptus tereticornis against a very high salinity concentration, 300 mM NaCl, known to cause inhibitory effects. Supplementing the microshoots of E. tereticornis with an optimized, 25 ppm IONP dose resulted in distinct biochemical changes in superoxide dismutase (∼3.8-fold rise in activity), malondialdehyde (lowered by ∼33%) concentration, and total soluble sugar (∼1.9-fold rise) and proline (11.8-fold rise) content, the biomarkers known to circumvent the stress response. The molecular mechanism of salt-responsive genes encoding HKT1, SOS1 and NHX1 indicated that IONPs can up-regulate their transcript levels either by the efflux of Na⁺ ions from the cell or by their sequestration in vacuole under stress conditions. Systematic analysis of morpho/physiological growth parameters also showed a remarkable increase in shoot length and the chlorophyll content by ∼2.5-fold and 128.5%, respectively, as compared to the control, under similar test conditions. Even under non-stressed conditions, IONPs acted as nano-supplements for promoting the shoot growth of E. tereticornis by increasing the gene expression of various antioxidant enzymes and synergistically improved the activity of catalase and peroxidase enzymes. This study strengthens our belief that nanomaterials could potentially be employed as a tool to enhance the performance of agroforestry trees under abiotic stress conditions. Furthermore, the impact of IONPs to replenish iron deficiency in soils concurrently with a superior salt stress tolerance could pave new pathways for managing the abiotic stresses in agroforestry.

中文翻译：

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氧化铁纳米颗粒的双重纳米酶特性减轻了盐分胁迫并促进了农林业树Eucalyptus tereticornis Sm的生长。

具有酶样活性的纳米材料在非生物胁迫等不利条件下具有巨大的改善植物生长的潜力。尽管已经证明了几种评估纳米生物相互作用的策略可以提高农作物/水果基植物的生产力，但尚未在农林业树木上进行此类尝试。在本文中，首次证明了使用氧化铁纳米颗粒（IONPs）的非生物胁迫处理方法在极高盐度浓度300 mM NaCl的尤加利桉树中被证明具有抑制作用。补充E. tereticornis的微照优化的25 ppm IONP剂量会导致超氧化物歧化酶（活性增加约3.8倍），丙二醛浓度（降低约33％）和总可溶性糖（增加1.9倍）和脯氨酸的明显生化变化11.8倍的上升）含量，已知可以避开压力反应的生物标志物。的编码盐应答基因的分子机制HKT1，SOS1和NHX1表明IONPs可以通过钠的流出上调其转录物水平⁺离子或通过在压力条件下将其隔离在液泡中而产生的离子。在相似的测试条件下，对形态/生理生长参数的系统分析还显示，与对照相比，枝条长度和叶绿素含量分别显着增加了约2.5倍和128.5％。即使在非胁迫条件下，IONP仍可作为纳米补充物来促进细小肠球菌的芽生长。通过增加各种抗氧化酶的基因表达并协同提高过氧化氢酶和过氧化物酶的活性。这项研究强化了我们的信念，即纳米材料可以潜在地用作在非生物胁迫条件下提高农林业树木性能的工具。此外，IONP在补充土壤中铁缺乏的同时具有优异的盐胁迫耐受性的影响可能为管理农林业中的非生物胁迫铺平了新途径。