Improvement of physiological indices and biological yield by intercropping of Kochia (Kochia scoparia), Sesbania (Sesbania aculeata) and Guar (Cyamopsis tetragonoliba) under the salinity stress of irrigation water.

Due to the low quality of water resources in arid and semi-arid regions of the world, selection and management of forage plants suitable for saline condition is of great importance. Intercropping systems with halophyte plants not only improve production efficiency but also reduce soil salinity. In this study, the effects of different levels of irrigation water salinity and intercropping system on physiological indices and biological yield of Kochia, Guar and Sesbania were investigated during the growing seasons of 2016 and 2017. A split plot experiment was conducted in a randomized complete block design with three replications. The main factor was salinity of irrigation water (4, 9 and 14 dS m-1) and the sub-factor was different cropping systems that consisted of mono cropping of Guar, Sesbania or Kochia, intercropping of two species and intercropping of three species. Results showed that salt stress increased sodium in the leaves of Kochia, Guar and Sesbania. Compared to mono cropping of Guar, in intercropping of three species and in intercropping with Kochia, Guar leaf potassium content was increased by 33.3% and 19.9% respectively. Salinity levels of 9 and 14 dS m-1 compared to salinity level of 4 dS m-1 increased the soluble sugar content of Kochia plant by 65.7% and 52.7%, respectively. However, in similar salinity levels, the trend for soluble sugar changes in Guar was vice versa. Salinity treatment of 14 dS m-1 decreased the relative water content of Sasbania and Guar leaves, but had a reverse effect on Kochia. Intercropping of two and three species also increased the relative water content of Sasbania and Guar leaves. Enhancement in salinity stress increased ionic leakage and malondialdehyde content of Guar leaf. On the other hand, at salinity level of 14 dS m-1, intercropping of three species increased the carotenoid content and decreased the amount of Guar leaf malondialdehyde compared to the Guar mono cropping system. The results of this study showed that salinity stress had negative effect on Guar yield but intercropping with Kochia could partly improve the yield of both Guar and Sesbania. In addition Kochia showed relatively good yield potential under salinity stress. Therefore, to improve the production of Sesbian and Guar, and also physiological performance of Kochia, intercropping system of these plants is recommended under salinity stress conditions.

Growth and nutrient content of Echinacea purpurea as affected by the combination of phosphorus with arbuscular mycorrhizal fungus and Pseudomonas florescent bacterium under different irrigation regimes.

The excessive use of chemical fertilizers has caused many environmental problems and threatens the health of the human communities at the global level. However, the use of some beneficial soil microorganisms in addition to supplying nutrients to plants helps protect the environment. In order to achieve this goal, the effects of different irrigation regimes and application of phosphorus (P) fertilizer, with mycorrhizal arbuscular fungus (AMF) or Pseudomonas fluorescens bacterium (PFB), were studied on the growth and nutrients of Echinacea purpurea. The main factor included soil irrigation after 25, 50 and 75% of soil moisture depletion and a sub-factor of P supplied in six levels (100% chemical P, 50% P + AMF, AMF, 50% P + PFB, PFB and a control test without P fertilizer). Results showed that an increase in drought intensity reduced the absorption of nutrients and relative water content (RWC), while ion leakage increased in the leaf of E. purpurea. The AMF had a more clear effect on the N, Cu, Mn, and Fe, but PFB was more effective in an increase of Zn. With the use of PFB in the second harvest, the amount of leaf and root Zn was increased by 30.39% and 31.88%, respectively. Although 100% chemical P could increase more P concentration in the root, the combination of P fertilizer with AMF transferred more P from root to leaf. In the first and second harvest, a combination of P with PFB respectively increased the plant biological yield by 10.77% and 17.33% as compared to control. Vegetative traits, Mn, and Zn illustrated a significant increase in the second harvest. Finally, the results showed successful coexistence of bio-fertilizers with E. purpurea in increasing the content of nutrients, improving water absorption, and reducing the adverse effects of drought stress.

Physiological and yield responses of purple coneflower (Echinacea purpurea (L.) Moench) to nitrogen sources at different levels of irrigation.

Echinacea purpurea (L.) is one of the most important medicinal plants in the world showing different biochemical reactions as affected by drought stress and nitrogen fertilizer. The purpose of this study was to determine the effect of nitrogen on soluble protein, enzyme activities, carotenoids metabolism, greenness and biological yield of the Echinacea purpurea under different levels of irrigation. The experiment was conducted in a research field in Iran during 2013-2015. Irrigation treatments included irrigation after 25, 50 and 75% soil water depletion, and nitrogen sources were no nitrogen (N), nitroxin, 40 kg N ha-1, 40 kg N ha-1 + nitroxin and 80 kg N ha-1. Nitroxin is a biofertilizer including Azotobacter and Azospirillum. The activity of catalase (11.9-21.3 mmol g-1fw min-1), peroxidase (40.1-48.9 µmol g-1fw min-1), polyphenoloxidase (0.79-3.63 mmol g-1fw min-1) increased in both years under drought stress conditions. The lowest greenness (50.1-45.9) was achieved from no-application of nitrogen in the irrigation treatment after 75% water depletion. The results demonstrated the beneficial effects of nitrogen sources on physiological reactions, especially peroxidase, polyphenol oxidase and carotenoids metabolism. It is concluded that irrigation of E. purpurea based on 50% water depletion and 80 kg nitrogen as well as the combination of nitroxin and 40 kg nitrogen treatments should be an appropriate choice for 2 years.

Evaluation of the benefits of plant growth-promoting rhizobacteria and mycorrhizal fungi on biochemical and morphophysiological traits of Aloe barbadensis Mill under water deficit stress.

Aloe barbadensis is a drought-tolerant perennial medicinal plant with both nutritional and cosmetic uses. Drought is one of the main abiotic stresses limiting plant growth and development. However, the use of drought-resistant plants combined with beneficial soil micro-organisms could improve the effectiveness of biological methods to mitigate drought damage. This research aims to evaluate the effects of Funneliformis mosseae (MF), plant growth-promoting rhizobacteria (PGPR) (including Pseudomonas putida and Pantoea agglomerans), and their co-inoculation on the macronutrient status, antioxidant enzyme activities, and other morphophysiological traits of A. barbadensis under four irrigation regimes [25%, 50%, 75% and 100% of water requirement (WR)]. Three harvests were conducted, revealing that inoculation enhanced the survival rate and shoot fresh weight (SFW) compared to the control plants. However, at 25% WR, the SFW was reduced by 43% more than the control. across all harvests, while the PGPR + MF treatment showed increases of more than 19%, 11%, and 17% compared to the control, MF, and PGPR treatments, respectively. The results also showed that A. barbadensis exhibited innate drought tolerance up to a 50% WR level by enhancing physiological defenses, such as antioxidant enzyme activity. Inoculation increased the macronutrient status of the plant at all levels of irrigation regimes especially under severe drought conditions. The highest levels of nitrogen (N) (16.24 mg g-1 DW) and phosphorus (P) (11.29 mg g-1 DW) were observed in the PGPR + MF treatment at 100% WR. The maximum relative water content under MF inoculation and 75% WR (98.24%) (98.24%) was reached. PGPR + MF treatment alleviated drought-induced osmotic stress, as indicated by reduced antioxidant enzyme activities and electrolyte leakage. However, P. putida and P. agglomerans strains alone or in combination with F. mosseae increased plant yield, macronutrient uptake and antioxidant enzyme activity. This study underscores the potential of these PGPR and MF strains as invaluable biological tools for the cultivation of A. barbadensis in regions with severe drought stress.

Biological activity of essential oils from Ferulago angulata and Ferula assa-foetida against food-related microorganisms (antimicrobial) and Ephestia kuehniella as a storage pest (insecticidal); an in vitro and in silico study.

Misuse of synthetic pesticides and antimicrobials in agriculture and the food industry has resulted in food contamination, promoting resistant pests and pathogen strains and hazards for humanity and the environment. Therefore, ever-increasing concern about synthetic chemicals has stimulated interest in eco-friendly compounds. Ferulago angulata (Schltdl.) Boiss. and Ferula assa-foetida L., as medicinal species with restricted natural distribution and unknown biological potential, aimed at investigation of their essential oil (EO) biological properties, were subjected. Z-ß-Ocimene and Z-1-Propenyl-sec-butyl disulfide molecules were identified as the major composition of the essential oil of the fruits of F. angulata and F. assa-foetida, respectively. In vitro antimicrobial activity and membrane destruction investigation by scanning electron microscopy imaging illustrated that F. angulata EO had potent antibacterial activity. Besides, the EOs of both plants exhibited significant anti-yeast activity against Candida albicans. In relation to insecticidal activity, both EOs indicated appropriate potential against Ephestia kuehniella; however, the F. assa-foetida EO had more toxicity on the studied pest. Among several insecticidal-related targets, acetylcholinesterase was identified as the main target of EO based on the molecular docking approach. Hence, in line with in vitro results, in silico evaluation determined that F. assa-foetida has a higher potential for inhibiting acetylcholinesterase and, consequently, better insecticide properties. Overall, in addition to the antioxidant properties of both EO, F. angulata EO could serve as an effective prevention against microbial spoilage and foodborne pathogens, and F. assa-foetida EO holds promise as a multi-purpose and natural biocide for yeast contamination and pest management particularly against E. kuehniella.

Co-inoculation of Mycorrhiza and methyl jasmonate regulates morpho-physiological and antioxidant responses of Crocus sativus (Saffron) under salinity stress conditions.

Salinity stress is the second most devastating abiotic factor limiting plant growth and yields. Climate changes have significantly increased salinity levels of soil. Besides improving the physiological responses under stress conditions, jasmonates modulate Mycorrhiza-Plant relationships. The present study aimed to evaluate the effects of methyl jasmonate (MeJ) and Funneliformis mosseae (Arbuscular mycorrhizal (AM) on morphology and improving antioxidant mechanisms in Crocus sativus L. under salinity stress. After inoculation with AM, pre-treated C. sativus corms with MeJ were grown under low, moderate, and severe salinity stress. Intense salinity levels damaged the corm, root, total leaf dry weight, and area. Salinities up to 50 mM increased Proline content and Polyphenol oxidase (PPO) activity, but MeJ increased this trend in proline. Generally, MeJ increased anthocyanins, total soluble sugars, and PPO. Total chlorophyll and superoxide dismutase (SOD) activity increased by salinity. The maximum catalase and SOD activities in + MeJ + AM were 50 and 125 mM, respectively, and the maximum total chlorophyll in -MeJ + AM treatment was 75 mM. Although 20 and 50 mM increased plant growth, using mycorrhiza and jasmonate enhanced this trend. Moreover, these treatments reduced the damage of 75 and 100 mM salinity stress. Using MeJ and AM can improve the growth of saffron under various ranges of salinity stress levels; however, in severe levels like 120 mM, this phytohormone and F. mosseae effects on saffron could be adverse.