The effects of mycorrhiza, Thiobacillus and Nitroxin (Azotobacter and Azospirillum sp.) biofertilizers under drought stress conditions with four levels of field capacity (FC) (control(100%), 85%, 70%, and 50%) on the antioxidant enzyme activities of medicinal pumpkin (Cucurbita pepo convar. pepo var. Styriaca) were evaluated during the years 2018–2019. Irrigation levels exhibited significant effects on all studied variables, except for the catalase (CAT) enzyme. A significant correlation was observed between the effects of irrigation levels and biofertilizers on antioxidant enzymes, soluble protein content, and grain yield. The highest activity of catalase and ascorbate peroxidase (APX) enzymes was achieved using mycorrhiza in 50% FC. Increasing drought intensity and mycorrhiza stimulated glutathione reductase (GR) and guaiacol peroxidase (GPX) activities by 32% and 66%, while Nitroxin increased them by 16% and 43%, respectively. Under severe drought stress conditions, only mycorrhiza exhibited a positive effect on GR and GPX enzymes. Under moderate and severe drought stress conditions, Nitroxin increased grain yield by 13% and 12.6%, respectively. The irrigation regimes and bio-fertilizers had a significant effect on β-sitosterol percentage. The highest amount was observed at the highest level of drought stress. Among the various bio-fertilizers treatments, the application of Thiobacillus yielded the highest percentage of β-sitosterol. The results of the present study demonstrate that the application of biofertilizers is beneficial in coping with drought stress.

Environmental factors, especially nutrients, can influence the production of medicinal plants. Thus, the present study assessed the response of some morphological and physiological characteristics of fennel ecotypes to the foliar application (magnetic water, organic and chemical fertilizers). The study was a factorial experiment based on the randomized complete block design, with three replications and 25 treatments at the research farm of the Agricultural and Natural Resources Research and Education Center of West Azerbaijan province, Iran, in the spring and summer of two consecutive years, 2014–2015 and 2015–2016. The first factor was assigned to fennel landraces (Gaziantep, Hamedan, Urmia, Yazd, and Shiraz) and the second factor to the foliar application (nitrogen nano-fertilizer, magnetic water, urea, chicken manure, and the control). Results showed that interaction of fertilizer treatment and landrace increased fresh and dry weight, biological yield, and seed yield significantly. In the first year, the highest fresh weight (166 g) and dry weight (35.5 g) were observed in the Gaziantep landrace fertilized with chicken manure. The highest anethole and fenchone contents (81.75% and 7.92%, respectively) were observed in the landraces treated with chicken manure. Based on the percentages, the Urmia landrace had the highest anethole percentage (83.2%), and the Shiraz landrace had the lowest one (77.5%). The highest fenchone contents (9.61%) and the lowest (2.18%) were observed in the Yazd and Urmia landraces. Due to the positive effect of application of chicken manure on improving the studied traits of fennel, it is recommended to include chicken manure inputs to enhance the efficiency of crops, reduce environmental pollution, and move toward sustainable agriculture.

The quantitative yield and essential oil percentage and composition of two important savory species in response to various fertilizers were explored in a field experiment as a factorial study based on a randomized complete block design with three replications in north Lorestan, Iran, in 2017–2019. The first factor was assigned to three mycorrhizal fungi (Funneliformis mosseae, Rhizophagus irregularis, and Glomus fasciculatum), phosphate biofertilizer (Baravar-2), fish manure (800 kg/ha), cattle manure (20 t/ha), vermicompost (5 t/ha), and a control (no fertilization); the second factor was assigned to two savory species, including Satureja khuzestanica and S. rechingeri. The results of the combined analysis of variance for the second and third years showed that the simple effects of fertilizers and species were significant on all recorded traits, except for some constituents of the essential oil. Among the mycorrhizal fungi, R. irregularis and S. khuzestanica outperformed S. rechingeri in all traits, except for essential oil content and yield. The interaction between year and species was significant for all traits. The essential oil content of S. rechingeri in the third year (5.1%) was 18% higher than that of S. rechingeri in the second year (4.3%) and 41% higher than that of S. khuzestanica in the third year (3.6%). According to the results, the foliar application of vermin compost at a rate of 5 t/ha can contribute to the sustainable production of both savory species, improving their growth and essential oil yield.

Foliar application or minerals is a methodology to promote growth and/or yield and to protect plants against different kinds of stresses. Currently there is a great interest in evaluating the effect of nanoparticles for enhancing the effect of these treatments. This study was performed to evaluate and compare the effect of foliar application of zinc oxide (ZnO) and zinc oxide nanoparticles (ZnO-NPs) on the growth and yield of safflower under different irrigation regimes. Foliar applications of ZnO in all concentrations (4, 6, 8, 10, 12, and 14 g L⁻¹) led to an increase in biomass yield, number of capitula per plant, number of seeds per capitulum, and grain yield of plants compared with control plants. The maximum increase in the studied traits was obtained with a ZnO concentration of 6, 8, and 10 g L⁻¹. In a second round of experiments, we observed the effect of nanoparticles and found that spraying with ZnO and ZnO-NPs at a concentration of 10 g L⁻¹ may ameliorate the deleterious effects of water deficit. The results of the present study support the idea that foliar application of ZnO improves safflower yield, especially under drought stress, and showed that using of nanoparticles increases the efficiency of the application.

Effects of Nano Fertilizer Application and Maternal Corm Weight on Flowering at Some Saffron (Crocus sativus L.) Ecotypes