Vermicompost Application in Different Intercropping Patterns Improves the Mineral Nutrient Uptake and Essential Oil Compositions of Sweet Basil (Ocimum basilicum L.)

Only a few studies have hitherto investigated the effects of the application of organic fertilizers in intercropping systems on the plant essential oil (EO) productivity. Hence, this work has aimed to study the effect of different intercropping patterns on EO quality and quantity of sweet basil (Ocimum basilicum L.) under vermicompost application. In the present study, the cropping patterns consisted of 1B:1CB, 2B:2CB, 3B:2CB, and 4B:2CB (basil: common bean) as well as the pure culture of both crops and fertilizer treatments including usage or non-usage of vermicompost. The maximum seed yield of common bean (2786 kg ha−1) and dry matter yield of basil in the first (261.5 g m−2) and second harvests (214.7 g m−2) were recorded in the pure cultures fertilized with vermicompost. In addition, the nutrient uptake rate of macronutrients and micronutrients in both plants after application of vermicompost improved in intercropping patterns. In both harvests, the maximum EO content of basil (0.84% in the first harvest and 0.69% in the second harvest) was observed at the cropping ratio of 3B:2CB fertilized with vermicompost. Chemical analysis, achieved by GC–MS, evidenced 1,8-cineole, linalool, methyl chavicol, α-trans-bergamotene, methyl eugenol, and epi-α-cadinol as the main basil EO constituents in both harvests. The highest increment level for most ofEO constituents, nutrient uptake, and land equivalent ratio (1.52) were obtained in the intercropping pattern of 3B:2CB fertilized with vermicompost. In general, the intercropping pattern of 3B:2CB after use of vermicompost can improve the EO productivity and quality of basil. This intercropping pattern was accompanied by the increment of nutrient uptake. Therefore, this treatment can be introduced as a valid and sustainable strategy to replace chemical fertilizer and plant monoculture

Essential oil variability in Stachys pilifera Benth populations: a narrow endemic species of Iran

Stachys pilifera Benth is an endemic species of Iran where it is found in the mountainous habitats of Zagros region. The plant is a rich source of secondary metabolites endowed with different medicinal properties. Here, for the first time, the essential oil vari- ability among eleven wild populations of S. pilifera, was investi- gated. Results indicated that the variation of the chemical profile of essential oils was remarkable. The most abundant components were cis-chrysanthenyl acetate (19.1-48.2%), viridiflorol (1.4-19.1%), trans-caryophyllene (2.3-11.9%), caryophyllene oxide (1.9-11.0%), limonene (2.0- 5.9%) and spathulenol (0.0- 9.5). Based on the cluster analyses (CA), four main chemotypes were recognized: chemotype I (cis-chrysanthenyl acetate), chemotype II (cis-chrysan- thenyl acetate/viridiflorol), chemotype III (cis-chrysanthenyl acetate/viridiflorol/spathulenol), chemotype IV (cis-chrysanthenyl acetate/trans-caryophyllene/a-pinene). The chemical variation detected can be useful to consider these populations for pharma- ceutical industries and industrial applications as well as for domestication and conservation purposes

Intraspecific divergence in phytochemical characteristics and drought tolerance of two carvacrol-rich Origanum vulgare subspecies: subsp. hirtum and subsp. gracile

Oregano, Origanum vulgare L., is a well-reputed medicinal herb used globally in cosmetics, food and pharma- ceutical industries. Essential oil (EO) composition and productivity of oregano subspecies are highly affected by water deficit stress. Here, a two-year (2018 and 2019) greenhouse study was conducted to comparatively investigate the impact of water deficit stress on biochemical traits and EO profiles of two carvacrol-rich sub- species of O. vulgare (subsp. gracile and subsp. hirtum). The pot-grown plants were subjected to four water stress treatments based on field capacity (FC) method, i.e., control condition (100 % FC), mild stress (75 % FC), moderate stress (50 % FC) and severe stress (35 % FC). Overall, the EO content of subsp. hirtum (up to 3.25 % (v/ w)) was higher than that of subsp. gracile (up to 1.92 % (v/w)). Compared with control, the EO contents increased by over 75 % under moderate water stress. Carvacrol was present in the EO profiles of both subspecies as the major component. Its highest content in the subsp. hirtum was achieved under mild water stress (i.e., 60 % (in 2018) and 68 % (in 2019)), whereas in the subsp. gracile, it was obtained under severe (55 % (in 2018)) and moderate (51 % (2019)) stresses. Overall, the subsp. hirtum showed higher dry weight, EO and carvacrol content than subsp. gracile. Furthermore, a significant positive correlation was observed among dry weight and EO content (r = 0.74, p < 0.01). On the other hand, there was a negative correlation between carvacrol and p- cymene content (r = − 0.60, p < 0.01). Water stress treatments inevitably reduced fresh weight, dry weight, relative water content and total chlorophyll content in both subspecies. However, the maximum quantum yield of PSII (Fv/Fm), superoxide dismutase and ascorbate peroxidase activity, and also proline content was changed in a subspecies-specific manner. The results of the present study enabled selection of the subsp. hirtum as a desirable prototype for relevant cultivation and prospective breeding programs

Evaluation of competition, essential oil quality and quantity of peppermint intercropped with soybean

Intercropping is a sustainable practice to achieve higher production per unit land area and time by maximizing the utilization of available resources. This work was aimed to study the effectiveness of peppermint/soybean intercropping patterns on the yield, quality of peppermint essential oil, competition and monetary indices in two years (2015–2016) and two harvests. The experiment was conducted in randomized complete block design keeping ratio of peppermint and soybean in 1:1, 1;2, 2:1, 2:3, 3:2, 1:3 and 3:1, respectively, along with sole plot of both crops. The results demonstrated that the highest biomass yield of peppermint in the first harvest was achieved in sole cropping pattern (317.2 g m−2) followed by 3:2, 3:1, 2:3 and 2:1 intercropping ratios. In the second harvest, the highest biomass yield of peppermint was recorded in peppermint monoculture (289.1 g m−2) and intercropping ratios of 3:2 and 3:1. In both harvests, the highest essential oil content and yield was obtained in the intercropping ratio of 3:2. Notably, the intercropping patterns gave 24.8% (first harvest) and 16.9% (second harvest) more essential oil than peppermint monoculture. Furthermore, the essential oil quality, in terms of high levels of menthol, 1,8-cineole, neo-iso-menthol, p-menth-1-en-9-ol, (E)-caryophyllene, (E)-β-farnesene and germacrene D and low content of menthofuran, improved significantly in intercropping treatments. The highest values of land equivalent ratio (LER), area time equivalent ratio (ATER), area harvest equivalent ratio (AHER), land use efficiency (LUE), monetary intercropping advantage (MAI) and system productivity index (SPI) were obtained in intercropping ratios of 2:3 and 3:2. Additionally, in all planting patterns the partial aggressivity (A) and crowding ratio (CR) values of peppermint were higher than soybean, indicating that the former was more competitive than the latter. According to our results, intercropping peppermint with soybean can improve the quality of peppermint essential oil and maintaining the crop productivity with limited external inputs; thus, this technique can be considered to be a sustainable practice for field management

Biomass Yield and Essential Oil Chemical Composition of Mentha x piperita as Affected by Amino Acids and Different Fertilizer Resources

The aim of this study was to answer the question of whether foliar application of amino acids along with chemical and organic fertilizers can be effective for peppermint growth characteristics, nutrient concentration, and essential oil content and composition. A split-plot experiment based on the randomized complete block design with three replications was used. The main factors included the following treatments: no fertilization (control), amino acid (AA), chemical fertilizer (CF), AA + CF, vermicompost (V), V + AA, farmyard manure (FYM), and FYM + AA. The sub-factor was represented by the first (H1) and second harvest (H2). The morphological traits and chlorophyll index values increased in peppermint after application of CF + AA and V + AA. The highest dry matter yield (274.3 gm−2), essential oil (EO) content (2.56%), and essential oil yield (EO) (7.04 gm−2) were obtained with V + AA at the first harvest. The highest concentrations of N, P, and Fe were observed with V + AA; those of K and Zn with FYM + AA; that of Mn with CF + AA at the second harvest. At both harvests, menthol, menthone, 1,8-cineole, neo-menthol, and δ-terpineol were the major components of peppermint essential oil. Menthol showed the highest value at H1 with FYM + AA (32.0%) and at the H2 with V + AA (38.4%). The correlation between the menthol content and the essential oil (EO) percentage and yield was significantly positive. The application of organic fertilizers such as vermicompost and farmyard manure integrated with amino acids can be a valuable alternative to chemical inputs and suitable treatment for improving the essential oil quantity and quality in peppermint

Sumac (Rhus coriaria L.) fruit: essential oil variability in Iranian populations

Sumac (Rhus coriaria L.), recognized in Iran and other areas of the Middle East as a very popular flavoring spice, contains a wide range of medicinally active components including organic acids, phenolic acids, flavonoids, anthocyanins, hydrolyzable tannins and terpenoids. In the present study, for the first time the variation of the essential oil compositions in R. coriaria fruits, collected from fourteen different locations in Iran, was assessed. A significant variability in the essential oil content was observed among the investigated populations (ranging from 0.04 to 0.19% (v/w)). GC-FID and GC–MS analyses of the essential oils identified a total of fifty-seven components. (E)-Caryophyllene (5.9–50.3%), n-nonanal (1.8–23.3%), cembrene (1.9–21.7%), α-pinene (0.0–19.7%), (2E,4E)-decadienal (2.4–16.5%) and nonanoic acid (0.0–15.8%) were identified as the main constituents of the essential oils, depending on the populations. The highest amounts of the mentioned components were identified in the essential oil of Tovrivar, Torbat jam, Qom, Kashmar, Torbat jam and Yazd populations, respectively. According to principal component (PCA) and cluster analyses (CA) the studied populations grouped into five different chemotypes: i.e., chemotype I ((E)-caryophyllene), chemotype II ((E)-caryophyllene/α-pinene), chemotype III ((E)-caryophyllene/cembrene), chemotype IV (nonanoic acid/cembrene), chemotype V (n-nonanal/(2E,4E)-decadienal). Such variability in essential oil compositions of Iranian sumac provides possibility to select populations with specific aroma profiles for domestication, breeding and industrial applications and suggests the effective in situ and ex situ conservation strategies for all populations and chemotypes of R. coriaria

Funneliformis mosseae application improve the oil quantity and quality and eco-physiological characteristics of soybean (Glycine max L.) under water stress conditions

The water deficit is one of the main limiting abiotic stress factors affecting the plant physiology, growth, and productivity. The aim of the present study was to evaluate the impact of bio-fertilizer application under water stress conditions on the soybean productivity and its oil quality as a new strategy in sustainable agriculture. The experimental treatments included different water irrigation regimes including irrigation after 20% (W20, well-watered conditions), 50% (W50, moderate water deficit), and 80% (W80, severe water deficit) soil water depletion, as well as inoculation and non-inoculation of arbuscular mycor- rhizal fungus (AMF). The results demonstrated that the seed yield, oil productivity, and oil yield of soybean decreased in moderate and severe water stress conditions. The maximum protein content (43.83%) was obtained in W50 water stress treated with AMF. AMF inoculation enhanced the seed and oil yields by 22.7 and 20.1% in comparison with control, respectively. In addition, the activity of antioxidant enzymes increased in water stress conditions treated with AMF. AMF inoculation improved the soybean oil quality as shown by the higher content of unsaturated fatty acids such as oleic and linoleic acids and lower content of saturated fatty acids such as palmitic and stearic acids. Application of AMF could be recommended as an eco-friendly strategy for improving soybean oil quality and quantity under water deficit conditions

Funneliformis mosseae inoculation under water deficit stress improves the yield and phytochemical characteristics of thyme in intercropping with soybean

Intercropping of medicinal plants/legumes along with bio-fertilizer application is a relatively new sustainable practice for improving the yield and secondary metabolites production. Here, a 2-years field experiment was performed to evaluate the effects of water deficit stress and arbuscular mycorrhizal fungi (AMF) application (as bio-fertilizer) on nutrients concentration, dry matter yield, essential oil quantity and quality of thyme in intercropping with soybean. Three irrigation levels, including (i) irrigation after depletion of 20% (I20) as non-stressed, 50% (I50) as moderate water deficit and 80% (I80) available water as severe water deficit were applied as the main factor. The sub-factor was represented by different cropping patterns including thyme sole culture, replacement intercrop ratio of 50:50 and 66:34 (soybean: thyme) and the third factor was non-usage (control) and usage of AMF. According to our results, the thyme dry yield under moderate and severe water deficit stress decreased by 35 and 44% in the first year, and by 27 and 40% in the second year compared with non-stressed (I20) plants, respectively. Also, the macro- and micro-nutrients of thyme leaves increased significantly in intercropping patterns after application of AMF. The maximum essential oil percentage of thyme was achieved in 50:50 intercropping ratio treated with AMF. Under moderate and severe water deficits, the major constituents of thyme essential oil including thymol, p-cymene and γ-terpinene were increased in intercropping patterns treated with AMF. Generally, AMF application in intercropping ratio of 50:50 may be proposed to farmers as an eco-friendly approach to achieve desirable essential oil quality and quantity in thyme under water deficit stress conditions

Chemical Composition and Antioxidant Activity of Essential Oils in Origanum vulgare subsp. gracile at different Phenological Stages and Plant Parts

Origanum vulgare, a popular flavoring herb, is valued for several biological properties. The present study focused on the chemical composition and antioxidant activity of the essential oils of Origanum vulgare subsp. gracile in different plant parts and at different phenological stages. Qualitative and quantitative analyses of the essential oil identified 41 constituents that varied with plant age and organ. The phenolic monoterpenoid carvacrol (18.1–79.2%) was predominant in all the essential oil samples. Other major constituents were p-cymene (3.9–18.0%), γ-terpinene (0.9–15.8%), carvacrol methyl ether (0.8–9.9%), and (Z)-α-bisabolene (0.5–8.7%). Among the different plant parts and phenological growth stages, the highest levels of carvacrol were identified in the essential oils from flowers (79.2%), roots (70%), and the early vegetative growth (67.34%). All the essential oils exhibited high radical-scavenging properties as shown in the DPPH* assay. The essential oils from flowers, however, exhibited the highest antioxidant activity and could be used as a preservative agent on an industrial scale

β-Aminobutyric acid treatment confers decay tolerance in strawberry fruit by warranting sufficient cellular energy providing

In this experiment, the mechanisms employed by β-aminobutyric acid (BABA) treatment to confer postharvest decay tolerance in strawberry fruit stored at 4 °C for 12 days were explored. Notably, BABA treatment at 25 mM conferred remarkably decay tolerance in strawberry fruit which was accompanied by higher membrane integrity representing by lower malondialdehyde (MDA) accumulation. Strawberry fruit treated with BABA exhibited remarkably higher cellular energy providing arising from higher H+-ATPase, Ca2+-ATPase, cytochrome c oxi- dase (CCO), and succinate dehydrogenase (SDH) enzymes activity. Additionally, strawberry fruit treated with BABA exhibited remarkably higher superoxide dismutase (SOD), catalase (CAT) and ascorbate peroxidase (APX) enzymes activity resulting in lower H2O2 accumulation. Also, higher phenylalanine ammonia lyase (PAL) en- zyme activity may be accountable for higher phenols and anthocyanins accumulation in strawberry fruit treated with BABA leading to superior DPPH scavenging capacity. Finally, strawberry fruit treated with BABA exhibited remarkably lower membrane degrading enzymes phospholipase D (PLD) and lipoxygenase (LOX) activity. According to our results, postharvest 25 mM BABA applying may be considered as a favourable strategy not only for conferring decay tolerance of strawberry fruit by warranting sufficient cellular energy providing, triggering H2O2 scavenging enzymes activity, enhancing phenols and anthocyanins accumulation and hampering mem- brane degrading enzymes activity which not only are vital for preserving membrane integrity, but also are crucial for keeping nutritional quality of strawberry fruit during postharvest cold storage