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Abstract：
The development and production of secondary metabolites from priceless medicinal plants are restricted by drought stress. Mentha pulegium L. belongs to the Lamiaceae family and is a significant plant grown in the Mediterranean region for its medicinal and aesthetic properties. This study investigated the effects of three polyethylene glycol (PEG) (0, 5, and 10%) as a drought stress inducer and four silicon nanoparticle (SiNP) (0, 25, 50, and 100 ppm) concentrations as an elicitor to overcome the adverse effect of drought stress, on the growth parameters and bioactive chemical composition of M. pulegium L. plants grown in vitro. The experiment was performed as a factorial experiment using a completely randomized design (CRD) consisting of 12 treatments with two factors (3 PEG × 4 SiNPs concentrations), 6 replicates were used for each treatment for a total of 72 experimental units.The percentage of shoot formation was inversely proportional to the PEG concentration; for the highest PEG concentration, the lowest percentage of shoot formation (70.26%) was achieved at 10% PEG. SiNPs at 50 ppm enhanced shoot formation, the number of shoots, shoot height, fresh and dry weight, rosmarinic acid, total phenols, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. The methanol extract from M. pulegium revealed the presence of significant secondary metabolites using gas chromatography‒mass spectrometry (GC-MS). The principal constituents of the extract were limonene (2.51, 2.99%), linalool (3.84, 4.64%), geraniol (6.49, 8.77%), menthol (59.73, 65.43%), pulegone (3.76, 2.76%) and hexadecanoic acid methyl ester or methyl palmitate (3.2, 4.71%) for the 0 ppm SiNPs, PEG 0% and 50 ppm SiNPs, and PEG 10%, respectively. Most of the chemical components identified by GC‒MS in the methanol extract were greater in the 50 ppm SiNP and 10% PEG treatment groups than in the control group. SiNP improves drought tolerance by regulating biosynthesis and accumulating some osmolytes and lessens the negative effects of polyethylene glycol-induced drought stress.Based on the results, the best treatment for most of the parameters was 50 ppm SiNPs combined with 10% PEG, the morphological and chemical characteristics were inversely proportional to the PEG concentration, as the highest PEG concentration (10%) had the lowest results. Most parameters decreased at the highest SiNP concentration (100 ppm), except for the DPPH scavenging percentage, as there was no significant difference between the 50 and 100 ppm SiNPs.
摘要：
干旱胁迫限制了无价药用植物次生代谢产物的开发和生产。MenthapulegiumL.属于唇形科，是地中海地区种植的重要植物，具有药用和美学特性。这项研究调查了三种聚乙二醇（PEG）（0、5和10％）作为干旱胁迫诱导剂和四种硅纳米颗粒（SiNP）（0、25、50和100ppm）浓度作为激发剂的作用，以克服干旱胁迫的不利影响，关于体外生长的M.pulegiumL.植物的生长参数和生物活性化学成分。该实验作为析因实验进行，使用完全随机设计（CRD），由12种具有两个因子（3PEG×4SiNPs浓度）的处理组成，每个处理使用6个重复,总共72个实验单元。芽形成的百分比与PEG浓度成反比；对于最高的PEG浓度，10％PEG时，芽形成的百分比最低（70.26％）。50ppm的SiNPs增强了芽的形成，射击的数量，射击高度,新鲜和干重，迷迭香酸,总酚，和2,2-二苯基-1-吡啶酰肼(DPPH)清除活性。使用气相色谱-质谱（GC-MS），从P中提取的甲醇提取物显示存在大量次生代谢产物。提取物的主要成分为柠檬烯（2.51，2.99％），芳樟醇（3.84，4.64％），香叶醇（6.49，8.77%），薄荷醇（59.73，65.43%），pulegone(3.76,2.76%)和十六烷酸甲酯或棕榈酸甲酯(3.2,4.71%)为0ppmSiNPs,PEG0%和50ppmSiNPs，和PEG10%，分别。在50ppmSiNP和10％PEG处理组中，甲醇提取物中通过GC-MS鉴定的大多数化学成分都比对照组高。SiNP通过调节生物合成和积累一些渗透压来提高耐旱性，并减轻聚乙二醇诱导的干旱胁迫的负面影响。根据结果,大多数参数的最佳处理是50ppmSiNPs与10％PEG组合，形态和化学特性与PEG浓度成反比，因为PEG浓度最高(10%)的结果最低。大多数参数在最高SiNP浓度（100ppm）时降低，除了DPPH清除百分比，因为50和100ppmSiNP之间没有显着差异。
