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In the present age of technological advancement, nanotechnology and its associated applications have been able to gain attention because of their ability to create a revolution in the field of modern science. There is no denying of the fact that nanomaterials synthesized by different methods, especially bio-synthesized ones, have provided numerous benefits to mankind in different fields like agriculture, medicine, industry, manufacturing etc. as they possess distinctive properties. Their size, surface characteristics and chemical composition are the major factors which contribute to their wide range of applications, while these are the same properties that are responsible for their toxic and hazardous effects. The present review tries to bridge an existing gap in literature – huge no. of research material is available of the technological advancements and applications of nanomaterials, paving the path for future research in this area, yet very limited information is available on their possible toxicity of living forms (plants, animals, humans alike) as well as the environment. This review acknowledges the tremendous advantages and positive effects of metal-based 11 NP: Nanoparticlesnanoparticles (NPs) on plants, but highlights on the phytotoxic effects of some of the most widely used NPs globally viz. ZnO NPs, TiO2 NPs, and AgNPs. Lastly, emphasis has been laid on the adverse effects of nanomaterials on different environmental conditions (soil and aquatic environment) and ecological topography.

Pot experiments were carried out to examine the biochar application and its alleviating effect on arsenic (As) toxicity in soybean plants. The data showed that As inhibits the growth indices and it increased with enhanced As-concentration in the substrate. The growth indices declined by more than 40% and the osmolyte concentration, photosynthetic pigments and antioxidant enzymes were decreased significantly among As-stressed plants. However, biochar application effectively mitigated the inhibitory effects of As on the soybean growth and the mitigation effect of treatment is more prevalent to the plants subjected to higher As-treatment. Biochar significantly reduced the As-uptake as revealed by the translocation factor (1), indicating more As is restrained in the roots. The reduction in the total chlorophyll and carotenoid content was found less in the As-treated soybean plants upon biochar application. Similarly, the osmolytes comprising proline, sugar and protein increased upon application of biochar. The biomarkers viz., membrane stability index (MSI), hydrogen peroxide and malondialdehyde (MDA) content significantly decreased at higher As-levels upon biochar application as was also supported by the heatmap analysis. Moreover, the antioxidative enzymes also showed a significant increase upon addition of biochar. Our data showed that biochar amendment effectively alleviates the As-stress by enhancing the sorption of As in the substrate thus, significantly declining the As concentration in plant leaves, and thus the results of the current study depicting the role of biochar as a promising, cost-effective and eco-friendly amendment to decontaminate the As-polluted soils.

The current study aimed to determine the mitigating effect of citric acid (CA) on various physiological and biochemical attributes in Withania coagulans, exposed to copper (Cu) stress. The viable seeds of Withania coagulans were planted in a controlled environment. After reaching the four-leaf stage, the plants were given simultaneous treatment with two concentrations of Cu [TCu1 and TCu2 (10mM, 15mM)] alone and/or with CA [TCa1 and TCa2 (05mM, 10mM)]. After harvesting, the physiological and biochemical characteristics of the plants were assessed. The findings demonstrated that using a higher dosage of Cu has significant toxic effects on plant growth and biomass. The agronomic attributes of the plant were significantly reduced by 24% (number of leaves), 22% (shoot length), 7% (root length), 8% (fresh weight), and 38% (dry weight) compared to the control. Higher concentration of Cu was also found toxic to photosynthetic pigments and significantly reduced by 27% (chl a), 6% (chl b), and 35% (carotenoids) compared to the control. However, the application of CA under Cu stress significantly improved the physiological attributes of Withania coagulans. The plant's agronomic traits significantly increased by 66% (number of leaves), 31% (shoot length), 87% (root length), 43% (fresh weight), and 78% (dry weight), whereas photosynthetic pigments by 25% (chl a), 58% (chl b), and 125% (carotenoids). Based on the results, it could be concluded that CA can play a role in mitigating the toxic effect of Cu in Withania coagulans

Aim Palms are an iconic, diverse and often abundant component of tropical ecosystems that provide many ecosystem services. Being monocots, tree palms are evolutionarily, morphologically and physiologically distinct from other trees, and these differences have important consequences for ecosystem services (e.g., carbon sequestration and storage) and in terms of responses to climate change. We quantified global patterns of tree palm relative abundance to help improve understanding of tropical forests and reduce uncertainty about these ecosystems under climate change. Location Tropical and subtropical moist forests. Time period Current. Major taxa studied Palms (Arecaceae). Methods We assembled a pantropical dataset of 2,548 forest plots (covering 1,191ha) and quantified tree palm (i.e., ≥10cm diameter at breast height) abundance relative to co‐occurring non‐palm trees. We compared the relative abundance of tree palms across biogeographical realms and tested for associations with palaeoclimate stability, current climate, edaphic conditions and metrics of forest structure. Results On average, the relative abundance of tree palms was more than five times larger between Neotropical locations and other biogeographical realms. Tree palms were absent in most locations outside the Neotropics but present in >80% of Neotropical locations. The relative abundance of tree palms was more strongly associated with local conditions (e.g., higher mean annual precipitation, lower soil fertility, shallower water table and lower plot mean wood density) than metrics of long‐term climate stability. Life‐form diversity also influenced the patterns; palm assemblages outside the Neotropics comprise many non‐tree (e.g., climbing) palms. Finally, we show that tree palms can influence estimates of above‐ground biomass, but the magnitude and direction of the effect require additional work. Conclusions Tree palms are not only quintessentially tropical, but they are also overwhelmingly Neotropical. Future work to understand the contributions of tree palms to biomass estimates and carbon cycling will be particularly crucial in Neotropical forests.

In response to the ongoing COVID-19 pandemic, the global effort to develop high efficacy countermeasures to control the infection are being conducted at full swing. While the efficacy of vaccines and coronavirus drugs are being tested, the microbiome approach represents an alternative pathophysiology-based approach to prevent the severity of the infection. In the current study, we evaluated the action of a novel probiotic Lactobacillus&nbsp, plantarum Probio-88 against SARS-COV-2 replication and immune regulation using an in vitro and in silico study. The results showed that extract from this strain (P88-CFS) significantly inhibited the replication of SARS-COV-2 and the production of reactive oxygen species (ROS) levels. Furthermore, compared with infected cells, P88-CFS treated cells showed a significant reduction in inflammatory markers such as IFN-α, IFN-β, and IL-6. Using an in silico molecular docking approach, it was postulated that the antiviral activity of L. plantarum Probio-88 was derived from plantaricin E (PlnE) and F (PlnF). The high binding affinity and formation of hydrogen bonding indicated that the association of PlnE and PlnF on SARS-COV-2 helicase might serve as a blocker by preventing the binding of ss-RNA during the replication of the virus. In conclusion, our study substantiated that P88-CFS could be used as an integrative therapeutic approach along with vaccine to contain the spread of the highly infectious pathogen and possibly its variants.

Background Mistletoe lectins (MLs) are obtained from the diverse species of Viscum album L., sharing an extensive history of their use as potent anticancer agents in the prevention and treatment of various cancers. Mistletoe lectin-I (ML-I) is highly investigated among all MLs for the anti-proliferative activity that arises from its cytotoxic and immunomodulatory functions. Methods Various databases, such as PubMed, Scopus, Web of Science, and Google Scholar, were searched up to 2020 using relevant keywords. Results In vitro and in vivo studies have signified apoptosis and cytokine production by immune cells as main mechanisms responsible for antitumor activities. MLs elicit the apoptotic pathway in tumour cell by regulating the expression of genes resulting in activation of caspases causing cell death. During apoptosis the disruption of the mitochondrial membrane leads to the release of cytochrome C and pro apoptotic factor Apaf-1 causing activation of Caspases. In addition, studies conducted on animal models have suggested that c-Myc, JNK and immune signalling systems as main oncotargets that mediate the antitumor functions. MLs are known to regulate the expression of genes involved in tumour survival, spread and growth. This includes down-regulation of anti-apoptotic proteins (Bcl-2), metalloproteinases, c-Myc protein, growth factor β genes while as up-regulation of pro-apoptotic proteins (Bax, Bad) and tumour necrosis factor (TNF).Transcriptomic and proteomic data also reported that cancer cells treated with whole plant Mistletoe extract constituting liphophillic Mistletoe compounds (triterpenes) and water soluble (lectins and viscotoxins) showed better anticancer efficacy than individual components while significantly affecting the genes involved in cell survival and death. Conclusion This review aims at exploring the antitumor mechanisms of MLs against various cancer cell lines and mice animal models which encourages its application as effective bio-therapeutic tools to address range of human cancers.

Invasive species are key operators of worldwide ecological change causing the loss of biodiversity, modifying structure and functioning of bio-system, and disturbing establishment of ecosystem amenities throughout the world. About 8.6% of the overall flora of India is alien. A considerable rise in worldwide trade and travel is expected to accelerate entry, spreading and eventual establishment of foreign species in India. Whereas the systematic catalogue of non-native species incarnates the primary vital stage, however, more comprehensive investigations on description of alien species in India, study of their potential invasion environments, recognition of possible ways of invasion and their impact on local vegetation are still missing. The present study reports the incidence of 173 species of alien flora in India, their origins from different parts of the globe belonging to a diverse array of families with an emphasis on the adverse effect of important invasive species on the local vegetation so as to generate an understanding of plant invasions and develop policy framework for their management.

The present investigation describes aluminum-induced changes in the leaves of two buckwheat species using both physiological and biochemical indices. With increasing levels of Al (viz. 100, 200 and 300 μM), the mean length of root, shoot as well as their biomass accumulation decreased linearly with respect to control. Tolerance test of F. kashmirianum revealed that it was more tolerant to Al-stress than F. tataricum as revealed by higher accumulation of Al in its roots without any significant damage. Translocation factor (TF) values of both species were found to be

The present study was designed to investigate the stimulatory effects of different doses (0.1 to 2.5 μM) of thidiazuron (TDZ) on in vitro shoot induction and proliferation of mature nodal explants of Tecoma stans. Of the tested concentrations, 2.0 μM TDZ proved to be optimal for maximum regeneration (91%) with a mean shoot number of 5.6 ± 0.67, and length of 2.38 ± 0.08 cm, after 4 wk of incubation. To determine the negative effects of prolonged TDZ exposure, after 4 wk of incubation at optimized level of TDZ, the cultures were transferred to a secondary medium either lacking plant growth regulators or supplemented with benzyladenine (BA) alone, or in combination with different auxins (indole-3-acetic acid, indole-3-butyric acid, or α-naphthalene acetic acid; NAA). Among the tested concentrations, 2.5 μM BA in combination with 0.5 μM NAA yielded the maximum mean shoot number (16.60 ± 0.40), and average shoot length (4.76 ± 0.15 cm) after 4 wk of culture. The best rhizogenesis (93%) was achieved on ½ MS medium containing 1.5 μM NAA, with a mean root number of 7.60 ± 0.40 and length of 4.11 ± 0.23 cm, after 4 wk of incubation. The micropropagated plantlets were successfully acclimatized and hardened off in Soilrite™ with a 90% survival rate. The plantlets grew well with normal growth, flowering and showed, by gas chromatography–mass spectroscopy, an increase in the number of bioactive compounds compared with the donor plant. This is the first report on T. stans in vitro regeneration using TDZ.

Mangroves are multi-functional ecosystems providing resource provisions and various ecosystem services, all of which are critical to the local livelihood and national economy. However, unsustainable anthropogenic activities continue to undermine the health of these ecosystems resulting in environmental adversities and declining resources. This study aimed to formulate a Mangrove Quality Index (MQI) which took into consideration the mangrove forest, contributing components of a mangrove forest, soil, surrounding marine ecosystem, hydrology and the socio-economic variables. Three major sites representing the least, moderately and most-disturbed mangrove ecosystems in Matang, Malaysia were selected. These areas were used to assess the contribution of 43 variables from five categories, namely, mangrove biotic integrity, mangrove soil, marine-mangrove, mangrove hydrology, and mangrove socio-economic factors. Two types of indices were developed to indicate the status of each category, 1) Mangrove Quality Index for a specific category (MQISi) and, 2) Overall MQI to reflect the overall health status of the ecosystem. The indices for the five different categories were Mangrove Biotic Integrity Index (MQIS1), Mangrove Soil Index (MQIS2), Marine-Mangrove Index (MQIS3), Mangrove-Hydrology Index (MQIS4) and Mangrove-Socio-economic Index (MQIS5). Using Principle Component Analysis, ten variables representing all the five categories were selected to formulate the overall MQI. They are aboveground biomass, crab abundance, soil carbon, soil nitrogen, number of phytoplankton species, number of diatom species, dissolved oxygen, turbidity, education level, and time spent fishing. We developed the overall MQI based on the total score obtained from each category. The health status of mangroves is ranked from 1 to 5 viz. 1 (worst), 2 (bad), 3 (moderate), 4 (good), 5 (excellent). In the Matang Mangrove, the health status of the least disturbed area is ranked 5, moderate disturbed area is ranked 4, while the most disturbed area is ranked 2. The Normalized Difference Vegetation Index (NDVI) supported the overall MQI developed. The NDVI for the least disturbed area in Matang ranged from −0.689846 to 0.652204, for the moderately disturbed area, it ranged from −0.732508 to 0.638625, while the most disturbed area ranged from −0.916667 to 0.314991.

Environmental variations resulting in biotic and abiotic stresses demand adaptive changes in the photosynthetic machinery. To cope with these challenges, plant scientists are constantly striving to enhance photosynthetic activity. The photorespiration pathway, which fixes O2 and releases CO2 in C3 plants, competes with photosynthesis. One method to increase yield would be to enhance photosynthesis by engineering the photorespiratory pathway. To date, three engineered photorespiratory pathways have been produced, of which two have been proven experimentally in the model plant, Arabidopsis thaliana. These approaches might be helpful in enhancing crop resilience to future environmental challenges. In partially photorespiratory suppressed plants, it is hypothesized that a gene cluster may have formed between bacterial glycolate dehydrogenase (GDH), glyoxylate carboligase (GCL), and tartronic semi aldehyde (TSR) genes with Arabidopsis allantoin degradation genes like Arabidopsis allantoinase (AtALN) to utilize S-allantoin as a source of nitrogen. Observations of the use of allantoin as an exclusive source of nitrogen or energy by Arabidopsis and Escherichia coli led us to propose a genetic switch control model between nitrogen assimilation and energy producing pathways in partially photorespiratory suppressed plants.

Drought is one of the major abiotic stress factors for plants, especially in arid and semiarid areas, where plants are facing with boron (B) contamination problem as well. In these soils, plants deal up with two destructive phenomena: excessive B and water scarcity. The current study aims to understand the adaptation strategy of tomato plant against excess B and drought stresses. For this purpose, hydroponically grown tomato seedlings were subjected with excess B (+B), drought (+PEG), and excess B with drought (B+PEG) stresses. Antioxidant enzyme activities (superoxide dismutase (SOD), ascorbate peroxidase (APX), and glutathione reductase (GR)); chlorophyll, soluble protein, and MDA contents; and the root histograms were analyzed. In addition, expression of stress-related genes (GR1, MT2, and Hsp90) was determined by qRT-PCR method. Compared to the non-treated (control) or B+ and PEG+ treated plants, the transcript abundance of the stress-related genes was significantly increased in plants grown under B+PEG condition. The highest relative increase was observed on GR1 gene (~ 7–8-fold), indicating the activation of oxidative stress enzymes. At the same time, chlorophyll content analysis showed a significant increase; MDA level showed a reduction under B+PEG condition. SOD activity was limited, while APX and GR enzymes were found to be increased upon B+PEG application. Activation of stress-related genes and antioxidant enzymes under B+PEG condition could help to protect plants against excess B and drought stresses. Inclusion of B can enhance the drought adaptation of plants by stimulating the early stress response mechanisms. © 2019, Sociedad Chilena de la Ciencia del Suelo. Department of Sport and Recreation, Government of Western Australia Deanship of Scientific Research, King Saud University Islamic Azad University: 2017-609-IRMC Part of this study is funded by Deanship of Scientific Research (DSR) fund of IAU (Imam Abdulrahman Bin Faisal University) as a grant number 2017-609-IRMC.

The stress induced by allelochemicals present in stem aqueous extract (SAE) of Nicotiana plumbaginifolia on alterations in growth, ultrastructure on Cassia tora L., and mitotic changes on Allium cepa L. were inspected. Application of SAE at different concentrations (0.5, 1, 2, and 4%) expressively reduced the growth of C. tora in terms of seedling length and dry biomass. Moreover, the ultrastructural variations induced in the epidermis of Cassia leaf (adaxial and abaxial surface) of 15-day-old saplings were analyzed through scanning electron microscopy (SEM). The variations noticed are rupturing and shrinking of cells along epidermis; damaged margins, extensively curled leaf apex along with the appearance of puff-like structures, grooves, and thread-like structures on the leaf surface. The epidermal cells of samples exposed to treatment no longer appear smooth relative to control, besides showing necrosis as well. Upon exposure to different concentrations of extract, A. cepa root tip cells showed aberrations in chromosome arrangement and disparity in the shape of the interphase and prophase nuclei along various phases of mitotic cycle as compared to control. The mitotic index (MI) showed a concentration-dependent decline in onion root tips exposed to SAE. The aberrations appearing frequently were formation of multinucleated cells, sticky metaphase and anaphase with bridges, sticky telophase, disturbed polarity, etc. The results also show the induction of elongated cells, giant cells, and cells with membrane damage by extract treatment. To our knowledge, this is the first gas chromatography-mass spectrometry (GC-MS) analysis of the methanolic extract of N. plumbaginifolia stem. Overall, 62 compounds were reported, covering 99.61% of the entire constituents, which can be considered responsible for the allelopathic suppression of C. tora. The chief component was 4-tert-butylcalix[4]arene with the highest composition of 19.89%, followed by palmitic acid (12.25%), palmitoleic acid (8.23%), precocene 2 (7.53%), isophytyl acetate (4.01%), and betastigmasterol (3.95%).

Graphical abstract, Currently, the available indices to measure mangrove health are not comprehensive. An integrative ecological-socio economic index could give a better picture of the mangrove ecosystem health. This method explored all key biological, hydrological, ecological and socio-economic variables to form a comprehensive mangrove quality index. A total of 10 out of 43 variables were selected based on principal component analysis (PCA). They are aboveground biomass, crab abundance, soil carbon, soil nitrogen, number of phytoplankton species, number of diatom species, dissolved oxygen, turbidity, education level and fishing time spent by fishers. Two types of indices were successfully developed to indicate the health status viz., (1) Mangrove quality index for a specific category (MQISi) and, (2) Overall mangrove quality index (MQI) to reflect the overall health status of the ecosystem. The indices for the five different categories were mangrove biotic integrity index (MQIS1), mangrove soil index (MQIS2), marine-mangrove index (MQIS3), mangrove-hydrology index (MQIS4) and mangrove socio-economic index (MQIS5). The quality of the mangroves was classified from 1 to 5 viz. 1 (worst), 2 (bad), 3 (moderate), 4 (good), 5 (excellent). These MQI class could reflect the quality of mangrove forest which could be managed with the objective of improving its quality. Advantages of this method include: • PCA to select metrics from ecological-socioeconomic variables • Formulation of MQI based on selected metrics • Comprehensive index to classify mangrove ecosystem health

Dumping waste materials into aquatic ecosystems leads to pollution, which directly and indirectly poses a danger to all life forms. Currently, huge quantities of wastes are generated at a global scale with varying constituents, including organic fractions, emerging contaminants and toxic metals. These wastes release concentrated contaminants (leachates), which are lethal for all ecosystems around the globe because they contain varying concentrations of chemical constituents with BOD5 and COD in the order of 2 x 10(4)-2.7 x 10(4) mg/L, and 3.4 x 10(4)-3.8 x 10(4) mg/L, respectively. Herein, in-depth knowledge of municipal solid waste dumping into the aquatic ecosystems, changes in physicochemical characteristics, availability of in-/organic contaminants, and long-term unhealthy effects are presented. Moreover, an attempt has been made here to summarize the facts related to identifying the deadly impacts of waste on different ecosystem components. The unresolved challenges of municipal waste management are emphasized, which will help employ suitable waste management techniques and technologies to conserve the everlasting freshwater resources on earth., 2232 International Fellowship for Outstanding Researchers Program of TuBITAK [2232, 118C212]; TuBITAK, This publication/paper has been produced benefiting from the 2232 International Fellowship for Outstanding Researchers Program of TuBITAK (Project No: 118C212) . However, the entire responsibility of the publication/paper belongs to the owner of the publication/paper. The financial support received from TuBITAK does not mean that the content of the publication is approved in a scientific sense by TuBITAK.

The study aimed at evaluating the antioxidant profile of a medicinal epiphyte Viscum album L. harvested from three tree species, namely, Populus ciliata L, Ulmus villosa L., and Juglans regia L. The crude extracts were obtained with ethanol, methanol, and water and were evaluated for the total phenol content (TPC), total flavonoid content (TFC), and antioxidant activities using total reducing power (TRP), ferric reducing antioxidant power (FRAP), 1, 1-diphenyl 1-2-picryl-hydrazyl (DPPH), superoxide radical scavenging (SOR), and hydroxyl radical scavenging (•OH) assays. Our results showed that crude leaf extracts of plants harvested from the host Juglans regia L. exhibited higher yields of phytochemical constituents and noticeable antioxidative properties. The ethanolic leaf samples reported the highest phenols (13.46 ± 0.87 mg/g), flavonoids (2.38 ± 0.04 mg/g), FRAP (500.63 ± 12.58 μM Fe II/g DW), and DPPH (87.26% ± 0.30 mg/mL). Moreover, the highest values for TRP (4.24 ± 0.26 μg/mL), SOR (89.79% ± 0.73 mg/mL), and OH (67.16% ± 1.15 mg/mL) were obtained from aqueous leaf extracts. Further, Pearson correlation was used for quantifying the relationship between TPC, TFC, and antioxidant (FRAP, DPPH, SOR, OH) activities in Viscum album L. compared to their hosts. It was revealed that the epiphyte showed variation with the type of host plant and extracting solvent.

The productivity of plants is a direct variant of the countless biotic and abiotic stresses to which a plant is exposed in an environment. This study aimed to investigate the capabilities of leguminous plant garden pea (Pisum sativum L.) to resist water deficit conditions in arid and semi-arid areas when applied with varied doses of sludge for growth response. The effect of sludge doses was evaluated on crop yield, antioxidant enzymes, viz., ascorbate peroxidase (APX), dehydroascorbate reductase (DHAR), superoxide dismutase (SOD), and glutathione reductase (GR), and metabolites (ascorbic acid, glutathione, and total protein content). The effective sludge concentrations with respect to seed weight and crop yield were found to be in the following trend: D

Salt stress adversely affects the growth and productivity of crops. However, reports suggest that the application of various micronutrients could help the plant to cope with this stress. Hence, the objective of the study was to examine the effect of exogenous application of Zinc (Zn) on salt tolerance in Vigna radiata (L.) Wilczek (mungbean). Mungbean is considered to be an economically important crop and possess a strategic position in Southeast Asian countries for sustainable crop production. It is rich in quality proteins, minerals and vitamins. Three weeks old grown seedlings were subjected to NaCl (150 mM and 200 mM) alone or with Zn (250 µM). After 21 days of treatment, plants were harvested for investigating morphological, physiological and biochemical changes. We found that the Zn application mitigates the negative effect upon plant growth to a variable extent. This may be attributed to the increased shoot and root length, improved chlorophyll and carotenoid contents, enhanced total soluble sugar (TSS), total soluble protein (TSP) and proline accumulation, decreased H2O2 content and increased enzymatic antioxidant activities. Zn’s application improved the performance of the enzymes such as phenylalanine ammonia-lyase (PAL) and tyrosine ammonia-lyase (TAL) of the secondary metabolism, which resulted in the improvement of total phenol and flavonoids. The antioxidant activities such as 1,1diphenyl 2-picryl hydrazine (DPPH) and ferrous reducing antioxidant power assay (FRAP) of the plants also showed improved results in their salt only treatments. Furthermore, hydrogen peroxide (H2O2) and superoxide radical (SOD) scavenging activity were also improved upon the application of 250 µM zinc. Thus, Zn application in low doses offers promising potential for recovering plants suffering from salinity stress. In conclusion, we assume that zinc application improved salt tolerance in mungbean through the improvement of various physiological and photochemical processes which could prove to be useful in nutrient mediated management for crop improvement.

The potential protective role of priming wheat seeds with maize green extract (MGE) against the stress effects of drought was studied. Pretreatment using MGE, MGE enriched with polyamines (MGEPA), and drought treatments (irrigation deficit of 30% (severe drought) or 60% (moderate drought) versus 90% relative water content of soil as a control) were applied in a factorial completely randomized design. Under moderate drought, pretreatment with MGEPA outperformed MGE and control, while severely stressed plants died even with pretreatments. Both extracts enhanced normal plant growth and yield and mitigated the deleterious effect of moderately stressed plants. Application of both extracts markedly increased photosynthetic efficiency, membrane stability, relative water content, and accumulation of antioxidants, osmoprotectants, trans- and cis-zeatin, polyamines, and their gene expressions, while levels of superoxide (O2•−) and hydrogen peroxide (H2O2), lipid peroxidation, and electrolyte leakage were decreased. Enzymatic antioxidants and glyoxalase system activities were improved in moderately stressed plants and were further improved with pretreatment with both extracts, thus protecting plants from oxidative damage by up-regulation of the ascorbate–glutathione cycle. Glycine betaine, soluble sugars, and proline levels were greatly increased in pretreated plants, thus maintaining membrane stability and photosynthetic efficiency. The interaction between drought and pretreatment using MGEPA was significant in growing wheat plants in dry environments with 60% relative water content of soil.

This study was conducted to determine the impact on the nutrient status of soil and vegetable crops irrigated with the treated sewage water. Three samples of water and five samples of soil and five commonly grown vegetables viz. radish, carrot, spinach, cauliflower, and potato were collected from Ganjia, Arail and Dandi located in Naini, Allahabad (India). The water samples were analysed for pH, EC, and heavy metals (Pb2+, Cr3+, Cd2+ and Ni2+) concentration. Water samples from all the sites were alkaline with EC below the safe limits. The soil and plant samples from all the three sites showed that Gangia recorded the highest value of EC (dS m-1), organic carbon (OC) (%), available NPK (kg ha-1), and micronutrients concentration (Mn2+, Zn2+ and Fe2+) (mg kg-1) whereas, the lowest concentration was recorded at Dandi followed by Arail. The soil samples collected from all three sites were alkaline. The nutrient status (N, P and K) showed the highest value in potato in the three sites, whereas manganese and zinc showed the highest value in spinach and iron in carrot. The study concludes that treated sewage water used for irrigation has a positive impact on nutrient status in soils and as well as in vegetable crops.

For maize, the potential preventive role of foliar spraying with an extract derived from maize grain (MEg, 2%), silymarin (Sm, 0.5 mM), or silymarin-enriched MEg (MEg-Sm) in attenuating the stress effects of cadmium (Cd, 0.5 mM) was examined using a completely randomized design layout. Under normal conditions, foliar spraying with MEg, Sm, or MEg-Sm was beneficial (with MEg-Sm preferred) for maize plants, whereas the benefit was more pronounced under Cd stress. The use of Cd through irrigation water decreased plant growth traits, photosynthetic efficiency, including instantaneous carboxylation efficiency, Fv/Fm, and pigment contents, and hormonal contents (e.g., auxin, gibberellins, cytokinins including trans-zeatin, and salicylic acid). These undesired findings were due to an increase in Cd content, leading to increased levels of oxidative stress (O2•− and H2O2), ionic leakage, and lipid peroxidation. Therefore, this damage resulted in an increase in the activities of nonenzymatic antioxidants, Sm, antioxidative enzymes, and enzyme gene expression. However, under Cd stress, although foliar spray with MEg or Sm had better findings than control, MEg-Sm had better findings than MEg or Sm. Application of MEg-Sm greatly increased photosynthesis efficiency, restored hormonal homeostasis, and further increased the activities of various antioxidants, Sm, antioxidative enzymes, and enzyme gene expression. These desired findings were due to the suppression of the Cd content, and thus the levels of O2•−, H2O2, ionic leakage, and lipid peroxidation, which were positively reflected in the growth and accumulation of dry matter in maize plants. The data obtained in this study recommend applying silymarin-enriched maize grain extract (MEg-Sm at 0.24 g Sm L‒1 of MEg) as a spray solution to maize plants when exposed to excess Cd in soil or irrigation water.

Abiotic stress occur when the environmental condition changes abundant to disturb the cellular functions. The most common stresses that frequently occur are salinity (in the form of NaCl), drought, heavy metals, flooding, and extreme temperature and heat. These major environmental stresses reportedly affect 90% of the world’s total arable land. Abiotic stress generally affects plant growth and development, and the effects may be general or non-specific such as reduction in growth, severely affected photosynthetic machinery, and excess of reactive oxygen species (ROS), which can lead to cell death. It has long been known that medicinal and aromatic plants (MAPs) have medicinal properties as they bear biologically active chemical substances such as saponins, tannins, essential oils, flavonoids, alkaloids, and other important chemical compounds. The quality and amount of these chemical metabolites in plants are influenced by a number of factors, mainly, among them, environmental stresses. Various morphological, physiological, and metabolic responses (negative or positive) have been noticed in various medicinal plants under different abiotic stresses. Nonetheless, induction in the level of different secondary metabolites in numerous medicinal plants under stress conditions has been reported. In the recent years, an ongoing and widely debated aspect in abiotic stress response is the regulatory role of plant growth regulators (PGRs). These are chemical substances that generally function as chemical messengers for intracellular communication and profoundly influence the growth and differentiation in plants. This chapter provided the deep insights of medicinal plants under different abiotic stress and role of different PGRs in abiotic stress tolerance mechanisms.

Nitrogen (N) is one of the indispensable nutrients required by plants for their growth, development, and survival. Being a limited nutrient, it is mostly supplied exogenously to the plants, to maintain quality and productivity. The increased use of N fertilizers is associated with high-cost inputs and negative environmental consequences, which necessitates the development of nitrogen-use-efficient plants for sustainable agriculture. Understanding the regulatory mechanisms underlying N metabolism in plants under low N is one of the prerequisites for the development of nitrogen-use-efficient plants. One of the important and recently discovered groups of regulatory molecules acting at the posttranscriptional and translational levels are microRNAs (miRNAs). miRNAs are known to play critical roles in the regulation of gene expression in plants under different stress conditions including N stress. Several classes of miRNAs associated with N metabolism have been identified so far. These nitrogen-responsive miRNAs may provide a platform for a better understanding of the regulation of N metabolism and pave a way for the development of genotypes for better N utilization. The current review presents a brief outline of miRNAs and their regulatory role in N metabolism.

Herbal medicines are the prime source of medical care for a great proportion of the population of the developing world. The control of human diseases by the use of plant products has several advantages besides being cheap to produce; they are biodegradable and readily available. Majority of the plant extracts have been found effective to combat human pathogenic bacteria without toxic side effects and environmental hazards. In the recent past, microbial infections such as candidiasis, tuberculosis, cryptococcosis, and salmonellosis have been increased partly due to HIV/AIDS pandemic. There is renewed interest in the search for plants with antimicrobial activity leading to various plants including Azadirachta indica, Camellia sinensis, Hypericum perforatum, and Allium sativum among others being investigated, and they displayed considerable antimicrobial activity. The possible mechanism of action of bioactive compounds of medicinal plants in traditional medicine has been demonstrated. Mechanism of action of these compounds in humans can largely be attributed to cytotoxicity, gene silencing, and immunopotentiation. The aim of the present chapter is to enlighten the potential medicinal properties of bioactive compounds of medicinal plants and also highlight their mode of action.

Dietary arsenic (As) contamination is a major public health issue. In the Middle East, the food supply relies primarily on the import of food commodities. Among different age groups the main source of As exposure is grains and grain-based food products, particularly rice and rice-based dietary products. Rice and rice products are a rich source of core macronutrients and act as a chief energy source across the world. The rate of rice consumption ranges from 250 to 650 g per day per person in South East Asian countries. The source of carbohydrates through rice is one of the leading causes of human As exposure. The Gulf population consumes primarily rice and ready-to-eat cereals as a large proportion of their meals. Exposure to arsenic leads to an increased risk of non-communicable diseases such as dysbiosis, obesity, metabolic syndrome, diabetes, chronic kidney disease, chronic heart disease, cancer, and maternal and fetal complications. The impact of arsenic-containing food items and their exposure on health outcomes are different among different age groups. In the Middle East countries, neurological deficit disorder (NDD) and autism spectrum disorder (ASD) cases are alarming issues. Arsenic exposure might be a causative factor that should be assessed by screening the population and regulatory bodies rechecking the limits of As among all age groups. Our goals for this review are to outline the source and distribution of arsenic in various foods and water and summarize the health complications linked with arsenic toxicity along with identified modifiers that add heterogeneity in biological responses and suggest improvements for multi-disciplinary interventions to minimize the global influence of arsenic. The development and validation of diverse analytical techniques to evaluate the toxic levels of different As contaminants in our food products is the need of the hour. Furthermore, standard parameters and guidelines for As-containing foods should be developed and implemented.