Improve Plant Productivity Research Articles

Dynamics of organic acid exudation and rhizobacteria in maize rhizosphere respond to N-CDs

To sustainably feed the growing global population, it is essential to increase crop yields on limited land while reducing the use of fertilizers and agrochemicals. The rhizosphere regulation shows significant potential to address this challenge. Here, foliar applied doping of nitrogen in carbon dots (N-CDs) entered maize leaves, and were transported to the stems and roots. The internalized N-CDs significantly increased the biomass (26.4–93.8%) and photosynthesis (17.0–20.3 %) of maize seedling during the three-week application of N-CDs, providing the substrate for tricarboxylic acid cycle (TCA) in shoots and roots. Correspondingly, more organic acids involved in TCA cycle, such as citric acid (14.0-fold), succinic acid (4.4-fold) and malic acid (3.4-fold), were synthesized and then secreted into rhizosphere after exposed to N-CDs for one day. As the exposure time increased, greater secretion of above organic acids by the roots was induced. However, no significant change was observed in the relative abundance of rhizobacteria after foliar application with N-CDs for one day. After one week, the relative abundances of Azotobacter, Bacillus, Lysobacter, Mucilaginibacter, and Sphingomonas increased by 0.8–3.8 folds. The relative abundance of more beneficial rhizobacteria (Sphingomonas, Lysobacter, Rhizobium, Azotobacter, Pseudomonas, Mucilaginibacter and Bacillus) enriched by 0.3–6.0 folds after two weeks, and Sphingomonas, Flavisolibacter and Bacillus improved by 0.6–3.2 folds after three weeks. These dynamic changes suggested that N-CDs initiate the synthesis and secretion of organic acids and then recruited beneficial rhizobacteria. The hierarchical partitioning analysis further indicated that N-CDs-induced secretion of organic acids from the roots was the main drivers of rhizobacteria community dynamics. The differential microbes altered by N-CDs were mainly involved in nitrogen (N) and phosphorus (P) cycles, which are beneficial for N and P uptake, and maize growth. These results provide insights into understanding the rhizosphere regulation of nanomaterials to improve plant productivity and nutrient-use efficiency.

Efficient scavenging of reactive carbonyl species in chloroplasts is required for light acclimation and fitness of plants.

Reactive carbonyl species (RCS) derived from lipid peroxides can act as critical damage or signaling mediators downstream of reactive oxygen species by modifying target proteins. However, their biological effects and underlying mechanisms remain largely unknown in plants. Here, we have uncovered the mechanism by which the RCS 4-hydroxy-(E)-2-nonenal (HNE) participates in photosystem II (PSII) repair cycle of chloroplasts, a crucial process for maintaining PSII activity under high and changing light conditions. High Light Sensitive 1 (HLT1) is a potential NADPH-dependent reductase in chloroplasts. Deficiency of HLT1 had no impact on the growth of Arabidopsis plants under normal light conditions but increased sensitivity to high light, which resulted from a defective PSII repair cycle. In hlt1 plants, the accumulation of HNE-modified D1 subunit of PSII was observed, which did not affect D1 degradation but hampered the dimerization of repaired PSII monomers and reassembly of PSII supercomplexes on grana stacks. HLT1 is conserved in all photosynthetic organisms and has functions in overall growth and plant fitness in both Arabidopsis and rice under naturally challenging field conditions. Our work provides the mechanistic basis underlying RCS scavenging in light acclimation and suggests a potential strategy to improve plant productivity by manipulating RCS signaling in chloroplasts.

Commonalities between the Atacama Desert and Antarctica rhizosphere microbial communities.

Plant-microbiota interactions have significant effects on plant growth, health, and productivity. Rhizosphere microorganisms are involved in processes that promote physiological responses to biotic and abiotic stresses in plants. In recent years, the interest in microorganisms to improve plant productivity has increased, mainly aiming to find promising strains to overcome the impact of climate change on crops. In this work, we hypothesize that given the desertic environment of the Antarctic and the Atacama Desert, different plant species inhabiting these areas might share microbial taxa with functions associated with desiccation and drought stress tolerance. Therefore, in this study, we described and compared the composition of the rhizobacterial community associated with Deschampsia antarctica (Da), Colobanthus quitensis (Cq) from Antarctic territories, and Croton chilensis (Cc), Eulychnia iquiquensis (Ei) and Nicotiana solanifolia (Ns) from coastal Atacama Desert environments by using 16S rRNA amplicon sequencing. In addition, we evaluated the putative functions of that rhizobacterial community that are likely involved in nutrient acquisition and stress tolerance of these plants. Even though each plant microbial rhizosphere presents a unique taxonomic pattern of 3,019 different sequences, the distribution at the genus level showed a core microbiome with a higher abundance of Haliangium, Bryobacter, Bacillus, MND1 from the Nitrosomonadaceae family, and unclassified taxa from Gemmatiamonadaceae and Chitinophagaceae families in the rhizosphere of all samples analyzed (781 unique sequences). In addition, species Gemmatirosa kalamazoonesis and Solibacter usitatus were shared by the core microbiome of both Antarctic and Desert plants. All the taxa mentioned above had been previously associated with beneficial effects in plants. Also, this microbial core composition converged with the functional prediction related to survival under harsh conditions, including chemoheterotrophy, ureolysis, phototrophy, nitrogen fixation, and chitinolysis. Therefore, this study provides relevant information for the exploration of rhizospheric microorganisms from plants in extreme conditions of the Atacama Desert and Antarctic as promising plant growth-promoting rhizobacteria.

Research Progress in Soybean by Phytohormone Modulation and Metal Chelation over the Past Decade

Phytohormones have been acknowledged as an eco-friendly and alternative source for plant growth promotion and abiotic stress tolerance. Heavy metal stress has attained considerable attention worldwide because of its serious effects. Globally, it is a major cause of crop yield loss. Soybean is an important legume crop that continuously faces environmental stress, such as heavy metal stress. The application of plant growth regulators, such as phytohormones, enhances plant tolerance toward heavy metals. Phytohormones augment the interaction with plants. They improve plant productivity under stress due to the potential of phytostabilization. They are capable of enhancing metal stress tolerance by reducing oxidation stress. In the present review, an attempt has been made to summarize the role of phytohormones in metal chelation in a model plant, soybean. The results suggest that among the phytohormones, ABA, JA, SA ET, GA, and IAA are synergistic with metal chelation, whereas cytokinins are antagonistic. The application of phytohormones and corresponding microbes enhances the production of glutathione (GSH), which enhances metal tolerance by metal sequestration.

A synthetic light-inducible photorespiratory bypass enhances photosynthesis to improve rice growth and grain yield

Bioengineering of photorespiratory bypasses is an effective strategy for improving plant productivity by modulating photosynthesis. In previous work, two photorespiratory bypasses, the GOC and GCGT bypasses, increased photosynthetic rates but decreased seed-setting rate in rice (Oryza sativa), probably owing to excess photosynthate accumulation in the stem. To solve this bottleneck, we successfully developed a new synthetic photorespiratory bypass (called the GMA bypass) in rice chloroplasts by introducing Oryza sativa glycolate oxidase 1 (OsGLO1), Cucurbita maxima malate synthase (CmMS), and Oryza sativa ascorbate peroxidase7 (OsAPX7) into the rice genome using a high-efficiency transgene stacking system. Unlike the GOC and GCGT bypass genes driven by constitutive promoters, OsGLO1 in GMA plants was driven by a light-inducible Rubisco small subunit promoter (pRbcS); its expression dynamically changed in response to light, producing a more moderate increase in photosynthate. Photosynthetic rates were significantly increased in GMA plants, and grain yields were significantly improved under greenhouse and field conditions. Transgenic GMA rice showed no reduction in seed-setting rate under either test condition, unlike previous photorespiratory-bypass rice, probably reflecting proper modulation of the photorespiratory bypass. Together, these results imply that appropriate engineering of the GMA bypass can enhance rice growth and grain yield without affecting seed-setting rate.

Recent progress on the microbial mitigation of heavy metal stress in soybean: overview and implications.

Plants are adapted to defend themselves through programming, reprogramming, and stress tolerance against numerous environmental stresses, including heavy metal toxicity. Heavy metal stress is a kind of abiotic stress that continuously reduces various crops' productivity, including soybeans. Beneficial microbes play an essential role in improving plant productivity as well as mitigating abiotic stress. The simultaneous effect of abiotic stress from heavy metals on soybeans is rarely explored. Moreover, reducing metal contamination in soybean seeds through a sustainable approach is extremely needed. The present article describes the initiation of heavy metal tolerance mediated by plant inoculation with endophytes and plant growth-promoting rhizobacteria, the identification of plant transduction pathways via sensing annotation, and contemporary changes from molecular to genomics. The results suggest that the inoculation of beneficial microbes plays a significant role in rescuing soybeans under heavy metal stress. They create a dynamic, complex interaction with plants via a cascade called plant-microbial interaction. It enhances stress metal tolerance via the production of phytohormones, gene expression, and secondary metabolites. Overall, microbial inoculation is essential in mediating plant protection responses to heavy metal stress produced by a fluctuating climate.

Combined application of acidic biochar and fertilizer synergistically enhances Miscanthus productivity in coastal saline-alkaline soil

Biochar amendment has been proven as an effective measure in the remediation of degraded soils, but few reports were focused on the interactive effects and mechanisms of biochar and fertilizer co-application in the amelioration of saline-alkaline soils. In this study, different biochar and fertilizer combinations were applied to investigate the interactive effect on fertilizer use efficiency, soil properties, and Miscanthus growth in a coastal saline-alkaline soil. Compared to the fertilizer or acidic biochar application alone, the combined application of acidic biochar and fertilizer significantly improved soil nutrient availability, ameliorated soil properties in rhizosphere soil. Meanwhile, the bacterial community structure and soil enzyme activities were considerably ameliorated. Additionally, the activities of anti-oxidant enzymes were substantially enhanced and the expression of abiotic stress-associated genes was significantly up-regulated in Miscanthus plants. Ultimately, the combined application of acidic biochar and fertilizer significantly enhanced Miscanthus growth and biomass accumulation in the saline-alkaline soil. Overall, our findings suggest that the combined application of acidic biochar and fertilizer represents a feasible and effective approach for improving plant productivity in saline-alkaline soils.

Algaeculture for agriculture: from past to future

The continuous growth of the world population has imposed major challenges on agriculture. Consequently, farmers generalized the overuse of synthetic fertilizers and pesticides to meet the global food demand. Although these products have helped many developing countries increase their crop yield, they have simultaneously resulted in many issues, mainly the decline of soil fertility and degradation of local ecosystems due to soil, water, and air contamination, combined with their non-renewable nature and increased costs. For agriculture to become more sustainable, the use of alternative biological products, with recognized beneficial effects on plant yield and health, must be expanded. In this context, microalgae and cyanobacteria are rich sources of nutrients and bioactive metabolites, which have been gaining attention from researchers and companies for their ability to improve plant nutrition, growth, and tolerance to stress. This review gives an overview of the research work that has been done in the last two decades, regarding the use of microalgae and cyanobacteria (blue-green algae) as biofertilizers, biostimulants, and biopesticides. This work identified trends and challenges and highlights the use of microalgae to recycle the nutrients from wastewater to improve plant productivity while reducing the fertilizer and water footprint for more sustainable agriculture practices.

Pre and postharvest characteristics of Dahlia pinnata var. pinnata, cav. As affected by SiO2 and CaCO3 nanoparticles under two different planting dates

Agriculture faces many challenges because of climate changes. The nutrients present in nano-sized form improve plant productivity, especially when used at the appropriate planting time. Field experiments were conducted as a factorial experiment for evaluating two planting dates (20th September and 20th October), foliar application with nanoparticles (NPs) including silica nanoparticles (SiO2-NPs) at 1.5 and 3 mM, calcium carbonate nanoparticles (CaCO3-NPs) at 5 and 10 mM and distilled water (control) on pre- and post-harvest characteristics of Dahlia pinnata var. pinnata Cav. The results indicate that the interactions during the late planting time (20th October) and exogenous applications of SiO2-NPs at 1.5 mM or CaCO3-NPs at 10 mM have improved plant growth including plant height, stem diameter, fresh and dry weights of plant, leaf area, inflorescence diameter, inflorescence stalk length, branches number, tuber numbers, inflorescences number on the plant, and the vase life. At the same time, insignificant differences appeared in the interaction during the planting dates and SiO2 or CaCO3 -NPs concentrations on inflorescence stalk diameter, total soluble solids, membrane stability index, maximum increase in fresh weight (FW), and Si and Ca contents. In addition, all exogenous applications of NPs at the late planting time promoted the plant growth characteristics like lignin %, cellulose %, inflorescence water content, change in FW, and total water uptake. Moreover, the controls through the two planting dates recorded the maximum change in water uptake and water loss values. In short, it can be recommended to use SiO2-NPs at 1.5 mM or CaCO3-NPs at 10 mM as a foliar application at the late planting time (20th October) for obtaining the optimum quantitative and qualitative parameters of D. pinnata.

Growth Responses of Potted Vitis vinifera Cultivars Differ to a Mycorrhizal Inoculant and Phosphorus Fertilizer

Biological amendments, such as arbuscular mycorrhizal (AM) fungal inoculant products, are increasingly incorporated into agricultural management plans as a way to improve plant productivity. However, the effects of mycorrhizal inoculants on plant growth are context-dependent and can vary with soil fertility and among plant cultivars. To optimize the use of mycorrhizal inoculant products on wine grapes at the nursery stage, we tested the effect of a mycorrhizal inoculant product with and without the addition of phosphorus (P) fertilizer on the growth and tissue nutrients of two popular Vitis vinifera cultivars, Merlot and Chardonnay. We rooted dormant cuttings in the following respective treatments: no AM fungal inocula or P fertilizer; AM fungal inocula; P fertilizer; and co-amendment of AM fungal inocula and P fertilizer. We grew the grapevines in pots for 5 months in a greenhouse. Growth responses to treatments differed between cultivars. ‘Merlot’ vines had a stronger growth response to the mycorrhizal inoculant product than ‘Chardonnay’, especially when no P fertilizer was added. The co-amendment of AM fungi and P fertilizer resulted in larger root biomass for ‘Merlot’, but there was no effect of any treatment on the root biomass of ‘Chardonnay’. ‘Merlot’ vines grown with the AM fungal inoculant product also had higher tissue P than uninoculated vines, but there was no effect of inoculation on tissue nutrients of ‘Chardonnay’. This study provides evidence of grapevine cultivar-specific responses to an AM fungal inoculant product in a greenhouse, which may be useful when planning nursery management strategies for the incorporation of biological amendments into grapevine production.

Chitosan and salty irrigation water affect morphological and physiological characteristics of rosemary herb

There are numerous uses for rosemary essential oil (Rosmarinus officinalis), including aromatherapy, antioxidant activity, antimicrobial and antitumour properties. High salinity of irrigation water is one of the main barriers inhibiting the growth of rosemary cultivation in Egypt's new reclamation zones. Chitosan is a natural biopolymer which is obtained from the deacetylation of chitin and has a high potential to improve plant productivity under stressful conditions. So, this study aimed to minimize the negative effects of salty irrigation water on rosemary plants by assisting them in adjusting to salt stress through foliar application of chitosan to determine the potential for increasing their cultivation in the new reclamation zones as a natural supply of essential oil. Rosemary plants were subjected to different doses of salty irrigation water (0, 25.7, 51.3, 77.0, 102.6 mM) without or with chitosan (6 mg L-1). Plants irrigated by salty water with spraying chitosan resulted in higher values of plant aerial parts, photosynthetic pigments, carbohydrates, protein, phenols, flavonoids, antioxidant enzymes (peroxidase and superoxide dismutase), essential oil, nitrogen, phosphorous and potassium than those irrigated by salty water without chitosan. In contrast, lower amounts were found in free radical scavenging, sodium and chloride of plant treated with salty water x chitosan than those treated with saline water only. Saline water, chitosan, and their interactions caused a number of changes in detected amino acids and essential oil components. It may be summarized that productivity of rosemary plants can be improved with adapting them under saline irrigation conditions by adding chitosan. This trial benefits the producers of rosemary to alleviate the hurtful effects of saline water in reclaimed regions with adding chitosan.

Prominent use of lactic acid bacteria in soil-plant systems

Lactic acid bacteria (LAB) are ubiquitous, Gram-positive, probiotic, and facultative aerophilic microorganisms. They are commonly found in wide range of environments including food-rich environments, decaying plants, milk products, the human gut, vaginal flora, and on the skin of various living organisms. These multifaceted bacteria have multiple roles including promoting food safety; promoting plant growth; improving soil, animal, and human health. They are also an integral part of sustainable farming strategies with a low risk of resistance to chemical pesticides, making them an environmentally friendly and effective way of managing pests and diseases and improving plant production. While the traditional role of LAB in food processing and human health sectors has been widely studied and documented, there is increasing attention to their additional roles that empirical evidences and research have validated such as serving as biofertilizers, biocontrol, and biostimulant agents in plant production through the production of bacteriocins, organic acids, and other compounds. However, there is still a gap in unlocking the relationship between LAB, soil, and plant hosts. Through a review of the literature and metadata, this review aims to discuss the less-explored relevance of LAB in soil-plant systems and spotlight the prospects for increased acceptance as sustainable and safe soil and plant health enhancers. The first part concentrates on analyzing the existing metadata, while the discussion part essentially focus on literature review.

From piggery wastewater to wheat using microalgae towards zero waste

Microalgae production is still expensive, driving the need to lower costs while strengthening the industry's environmental sustainability. Microalgae are recognized tools for efficient wastewater treatment, offering the recycling of nutrients and water for agriculture, and producing biomass rich in growth-promoting compounds to improve plant productivity and resistance to adverse conditions. The use of wastewater can reduce cultivation costs as it is a source of nutrients and water. Alternative low-cost methods can significantly decrease harvesting costs, which represents one of the most expensive steps of the whole process.The goal of this work was to evaluate the potential of wastewater-grown microalga biomass for agriculture purposes. To reduce production costs, the microalga Tetradesmus obliquus was produced in pre-treated photo-Fenton (PF) piggery wastewater in combination with the use of different harvesting techniques - electrocoagulation, flocculation, and centrifugation, and different combinations. From the wastewater treatment process, two fractions (biomass and supernatant) were evaluated for germination and growth of wheat (Triticum aestivum L.) plants and compared to non-harvested microalga culture (MC), distilled water, and Hoagland (synthetic) solution. The concentrated resulting from PF was also tested as a biofertilizer.The results confirm that both biomass and supernatants are useful for agricultural applications. The obtained biomass elicited a 20–105 % increase in germination index compared to the control, while supernatants were inhibiting. The opposite trend was observed at later stages of wheat growth, where the nutrient-enriched supernatants and the PF concentrate (PF-CC) increased the number of tillers (3–5) and leaves (30–42) after 83 days. Wheat plants treated with MC and PF-CC produced similar number of ears (3.4 ± 0.5 and 6.0 ± 4.1 ears per plant, respectively) than the synthetic control (5.7 ± 1.4) after 182 days. All fractions obtained from the process can be used in a zero-waste process.

Modified green waste compost as growing substrates on the effective components of medicinal plants perilla (Perilla frutescens (L.) Britt.) and mint (Mentha haplocalyx Briq.)

Soilless substrates supporting plant production have been the research focus in recent decades. Green waste compost (GWC)-based substrates have shown the feasibility in improving plant production, but the research of GWC as growing substrate to improve the quality of medicinal plants was limited. The objective of this study was to explore the effects of GWC substrates modified by matured peanut shell (MPS, at 0, 10, 20 %; by vol.) and humic acid (HA, at 0, 3, 6 %; by weigh.) on the effective components of medicinal plants perilla (Perilla frutescens (L.) Britt.) and mint (Mentha haplocalyx Briq.). The 100% GWC substrates was used as control. The hydrologic-physical and biochemical properties of growing substrates and the biomass accumulation, secondary metabolite synthesis, essential oil production, and chemical composition of both herbs were investigated. Results showed that both perilla and mint grown in GWC substrates amended with MPS and HA had better performance than the control. The addition of additives (MPS and HA) positively affected the biomass accumulation of perilla and mint. The combination of the highest doses of MPS and HA (20 % and 6 %, respectively) resulted in an accumulation of total fresh weight and total dry weight several times (the total fresh and dry weight of perilla was 2.70 and 2.37 times, the total fresh and dry weight of mint was 1.47 and 1.51 times, respectively) greater than that of the control. Furthermore, the addition of MPS and HA could improve the secondary metabolite synthesis of mint and perilla and this synthesis was related to the hydrologic-physical and biochemical properties of growing substrates. Unexpectedly but reasonably, perilla was more sensitive to the addition of MPS while there was no significant (p < 0.05) correlation between the addition of MPS or HA for mint and the addition of HA for perilla. Notably, the best effective components of both herbs were achieved when perilla grown in GWC modified by 20 % MPS and 3 % HA and mint grown in GWC modified by 10 % MPS and 6 % HA. Overall, the quality of GWC could be effectively modified by the addition of MPS and HA and the modified GWC could be used as an environmentally and friendly substrate to improve the effective components of mint and perilla.

Reviewing and renewing the use of beneficial root and soil bacteria for plant growth and sustainability in nutrient-poor, arid soils.

A rapidly increasing human population coupled with climate change and several decades of over-reliance on synthetic fertilizers has led to two pressing global challenges: food insecurity and land degradation. Therefore, it is crucial that practices enabling both soil and plant health as well as sustainability be even more actively pursued. Sustainability and soil fertility encompass practices such as improving plant productivity in poor and arid soils, maintaining soil health, and minimizing harmful impacts on ecosystems brought about by poor soil management, including run-off of agricultural chemicals and other contaminants into waterways. Plant growth promoting bacteria (PGPB) can improve food production in numerous ways: by facilitating resource acquisition of macro- and micronutrients (especially N and P), modulating phytohormone levels, antagonizing pathogenic agents and maintaining soil fertility. The PGPB comprise different functional and taxonomic groups of bacteria belonging to multiple phyla, including Proteobacteria, Firmicutes, Bacteroidetes, andActinobacteria,among others. This review summarizes many of the mechanisms and methods these beneficial soil bacteria use to promote plant health and asks whether they can be further developed into effective, potentially commercially available plant stimulants that substantially reduce or replace various harmful practices involved in food production and ecosystem stability. Our goal is to describe the various mechanisms involved in beneficial plant-microbe interactions and how they can help us attain sustainability.

Abundance and distribution of arbuscular mycorrhizal fungi associated with oil-yielding plants.

Due to their role in nutrient transmission, arbuscular mycorrhizal fungi (AMF) are widespread plant root symbionts. They may improve plant production by altering plant community structure and function. Therefore, a study was conducted in the state of Haryana to analyze the distribution pattern, diversity, and association of different AMF species with oil-yielding plants. The results of the study revealed the percentage of root colonization, sporulation, and diversity of fungal species associated with the selected 30 oil-yielding plants. The percentage root colonization ranged from 0% to 100%, the highest in Helianthus annuus (100.00 ± 0.00) and Zea mays (100.00 ± 0.00) and the least in Citrus aurantium (11.87 ± 1.43). At the same time, there was no root colonization in the Brassicaceae family. The number of AMF spores present in 50 g of soil samples varied from 17.41 ± 5.28 to 497.2 ± 8.38, with maximum spore population in Glycine max (497.2 ± 8.38) and minimum in Brassica napus (17.41 ± 5.28). Besides, the presence of several species of different genera of AMF was reported in all the studied oil-yielding plants, that is, 60 AMF belonging to six genera viz. Acaulospora, Entrophospora, Glomus, Gigaspora, Sclerocystis, and Scutellospora were observed. Overall, this study will promote AMF usage in oil-yielding plants.

Organic materials to enhance climate change resilience on shallot production: a review

Shallot is one of the most important vegetables for Indonesian people due to its circumstances as the main ingredient in many Indonesian foods. The use of organic materials as nutrient sources is growing, concerning the increasing consumer demands on organic products and environmental issues such as climate change. Using organic materials helps plants to mitigate and adapt the environmental changes. This review described the potential organic sources as liquid organic fertilizer to support shallot growth. The method of this review was a systematic literature review that was grouped by themes. Liquid organic fertilizer is one of the most effective ways to improve plant production. The results showed that the effect of liquid organic fertilizer depends on the raw materials that were used. Several organic materials that potentially enhance shallot production and quality would be discussed, including rabbit manure, black soldier fly manure (kasgot) and white lead tree leaves. Those organic materials contain a high concentration of phosphorus, potassium and nitrogen that might accelerate shallot growth. The potential effect of those organic materials on increasing shallot production would be described briefly.

Long distance signalling and epigenetic changes in crop grafting.

Humans have used grafting for more than 4000 years to improve plant production, through physically joining two different plants, which can continue to grow as a single organism. Today, grafting is becoming increasingly more popular as a technique to increase the production of herbaceous horticultural crops, where rootstocks can introduce traits such as resistance to several pathogens and/or improving the plant vigour. Research in model plants have documented how long-distance signalling mechanisms across the graft junction, together with epigenetic regulation, can produce molecular and phenotypic changes in grafted plants. Yet, most of the studied examples rely on proof-of-concept experiments or on limited specific cases. This review explores the link between research findings in model plants and crop species. We analyse studies investigating the movement of signalling molecules across the graft junction and their implications on epigenetic regulation. The improvement of genomics analyses and the increased availability of genetic resources has allowed to collect more information on potential benefits of grafting in horticultural crop models. Ultimately, further research into this topic will enhance our ability to use the grafting technique to exploit genetic and epigenetic variation in crops, as an alternative to traditional breeding.

Mediation of gaseous emissions and improving plant productivity by DCD and DMPP nitrification inhibitors: Meta-analysis of last three decades

Nitrification inhibitors (NIs), especially dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP), have been extensively investigated to mitigate nitrogen (N) losses from the soil and thus improve crop productivity by enhancing N use efficiency. However, to provide crop and soil-specific guidelines about using these NIs, a quantitative assessment of their efficacy in mitigating gaseous emissions, worth for nitrate leaching, and improving crop productivity under different crops and soils is yet required. Therefore, based upon 146 peer-reviewed research studies, we conducted a meta-analysis to quantify the effect of DCD and DMPP on gaseous emissions, nitrate leaching, soil inorganic N, and crop productivity under different variates. The efficacy of the NIs in reducing the emissions of CO2, CH4, NO, and N2O highly depends on the crop, soil, and experiment types. The comparative efficacy of DCD in reducing N2O emission was higher than the DMPP under maize, grasses, and fallow soils in both organic and chemical fertilizer amended soils. The use of DCD was linked to increased NH3 emission in vegetables, rice, and grasses. Depending upon the crop, soil, and fertilizer type, both the NIs decreased nitrate leaching from soils; however, DMPP was more effective. Nevertheless, the effect of DCD on crop productivity indicators, including N uptake, N use efficiency, and biomass/yield was higher than DMPP due to certain factors. Moreover, among soils, crops, and fertilizer types, the response by plant productivity indicators to the application of NIs ranged between 35 and 43%. Overall, the finding of this meta-analysis strongly suggests the use of DCD and DMPP while considering the crop, fertilizer, and soil types.Graphical

Date palm-magnetized biochar for in-situ stabilization of toxic metals in mining-polluted soil: evaluation using single-step extraction methods and phytoavailability

Mining activities provide a pathway for the entry and accumulation of various heavy metals in soil, which ultimately leads to severe environmental pollution. Utilization of various immobilizing agents could restore such contaminated soils. Therefore, in this study, date palm-derived biochars (BCs: produced at 300 °C, 500 °C and 700 °C) and magnetized biochars (MBCs) were employed to stabilize heavy metals (Cd, Pb, Cu and Zn) in mining polluted soil. Metal polluted soil was amended with BCs and MBCs at w/w ratio of 2% and cultivated with wheat (Triticum aestivum L.) in a greenhouse. After harvesting, dry and fresh biomass of plants were recorded. The soil and plant samples were collected, and the concentrations of heavy metals were measured after extracting with water, DTPA (diethylenetriaminepentaacetic acid), EDTA (ethylenediaminetetraacetic acid), and acetic acid. BCs and MBCs resulted in reduced metal availability and uptake, with higher fresh and dry biomass (>36%). MBCs showed maximum decrease (>70%) in uptake and shoot concentration of metals, as these reductions for Cd and Pb reached below the detection limits. Among all single-step extractions, the DTPA-extractable metals showed a significant positive correlation with shoot concentrations of tested metals. Thus, the synthesized BCs and MBCs could effectively be used for stabilizing heavy metals and improve plant productivity in multi-contaminated soils. However, future studies should focus on long term field trials to restore contaminated mining soils using modified biochars.