Farouk Saad, Al-Huqail Arwa Abdulkreem
Agricultural Botany Department, Faculty of Agriculture, Mansoura University, Mansoura 35516, Egypt.
Department of Biology, College of Science, Princess Nourah Bint Abdulrahman University, P.O. Box 84428, Riyadh 11671, Saudi Arabia.
Plants (Basel). 2022 Mar 13;11(6):765. doi: 10.3390/plants11060765.
Salinity is persistently a decisive feature confining agricultural sustainability and food security in arid and semi-arid regions. Biochar (Bi) has been advocated as a means of lessening climate changes by sequestering carbon, concurrently supplying energy and rising crop productivity under normal or stressful conditions. Melatonin (Mt) has been shown to mediate numerous biochemical pathways and play important roles in mitigating multi-stress factors. However, their integrated roles in mitigating salt toxicity remain largely inexpressible. A completely randomized design was conducted to realize the remediation potential of Bi and/or Mt in attenuation salinity injury on borage plants by evaluating its effects on growth, water status, osmotic adjustment, antioxidant capacity, ions, and finally the yield. Salinity stress significantly decreased the plant growth and attributed yield when compared with non-salinized control plants. The depression effect of salinity on borage productivity was associated with the reduction in photosynthetic pigment and ascorbic acid (AsA) concentrations, potassium (K) percentage, K-translocation, and potassium/sodium ratio as well as catalase (CAT) activity. Additionally, borage plants' water status was disrupted by salinity through decreasing water content (WC), relative water content (RWC), and water retention capacity (WTC), as well as water potential (Ψw), osmotic potential (Ψs), and turgor potential (Ψp). Moreover, salinity stress evoked oxidative bursts via hyper-accumulation of hydrogen peroxide (HO) and malondialdehyde (MDA), as well as protein carbonyl, which is associated with membrane dysfunction. The oxidative burst was connected with the hyper-accumulation of sodium (Na) and chloride (Cl) in plant tissues, coupled with osmolytes' accumulation and accelerating plants' osmotic adjustment (OA) capacity. The addition of Bi and/or Mt had a positive effect in mitigating salinity on borage plants by reducing Cl, Na, and Na-translocation, and oxidative biomarkers as well as Ψw, Ψs, and Ψp. Moreover, Bi and/or Mt addition to salt-affected plants increased plant growth and yield by improving plant water status and OA capacity associated with the activation of antioxidant capacity and osmolytes accumulation as well as increased photosynthetic pigments, K, and K/Na ratio. Considering these observations, Bi and/or Mt can be used as a promising approach for enhancing the productivity of salt-affected borage plants due to their roles in sustaining water relations, rising solutes synthesis, progressing OA, improving redox homeostasis, and antioxidant aptitude.
盐分一直是限制干旱和半干旱地区农业可持续性和粮食安全的决定性因素。生物炭（Bi）被认为是一种通过固碳来减缓气候变化的手段，同时在正常或胁迫条件下提供能量并提高作物生产力。褪黑素（Mt）已被证明可介导多种生化途径，并在减轻多种胁迫因素方面发挥重要作用。然而，它们在减轻盐毒性方面的综合作用仍 largely难以言表。通过评估其对生长、水分状况、渗透调节、抗氧化能力、离子以及最终产量的影响，进行了完全随机设计，以实现Bi和/或Mt在减轻盐胁迫对琉璃苣植物伤害方面的修复潜力。与非盐渍化对照植物相比，盐胁迫显著降低了植物生长并导致产量下降。盐度对琉璃苣生产力的抑制作用与光合色素和抗坏血酸（AsA）浓度、钾（K）百分比、K转运、钾/钠比以及过氧化氢酶（CAT）活性的降低有关。此外，盐度通过降低水分含量（WC）、相对含水量（RWC）和保水能力（WTC）以及水势（Ψw）、渗透势（Ψs）和膨压势（Ψp）破坏了琉璃苣植物的水分状况。此外，盐胁迫通过过氧化氢（HO）和丙二醛（MDA）以及蛋白质羰基的过度积累引发氧化爆发，这与膜功能障碍有关。氧化爆发与植物组织中钠（Na）和氯（Cl）的过度积累以及渗透溶质的积累和植物渗透调节（OA）能力的加速有关。添加Bi和/或Mt通过降低Cl、Na和Na转运以及氧化生物标志物以及Ψw、Ψs和Ψp，对减轻琉璃苣植物的盐胁迫有积极作用。此外，向受盐影响的植物中添加Bi和/或Mt通过改善植物水分状况和OA能力来增加植物生长和产量，这与抗氧化能力和渗透溶质积累的激活以及光合色素、K和K/Na比的增加有关。考虑到这些观察结果，Bi和/或Mt因其在维持水分关系、增加溶质合成、促进OA、改善氧化还原稳态和抗氧化能力方面的作用，可作为提高受盐影响的琉璃苣植物生产力的一种有前景的方法。
