Nutrient Uptake Efficiency Research Articles

Distinct Effects of Chemical Toxicity and Radioactivity on Metabolic Heat of Cultured Cells Revealed by "Isotope-Editing".

Studying the toxicity of chemical compounds using isothermal microcalorimetry (IMC), which monitors the metabolic heat from living microorganisms, is a rapidly expanding field. The unprecedented sensitivity of IMC is particularly attractive for studies at low levels of stressors, where lethality-based data are inadequate. We have revealed via IMC the effect of low dose rates from radioactive β--decay on bacterial metabolism. The low dose rate regime (<400 µGyh-1) is typical of radioactively contaminated environmental sites, where chemical toxicity and radioactivity-mediated effects coexist without a predominance or specific characteristic of either of them. We found that IMC allows distinguishing the two sources of metabolic interference on the basis of "isotope-editing" and advanced thermogram analyses. The stable and radioactive europium isotopes 153Eu and 152Eu, respectively, were employed in monitoring Lactococcus lactis cultures via IMC. β--emission (electrons) was found to increase initial culture growth by increased nutrient uptake efficiency, which compensates for a reduced maximal cell division rate. Direct adsorption of the radionuclide to the biomass, revealed by mass spectrometry, is critical for both the initial stress response and the "dilution" of radioactivity-mediated damage at later culture stages, which are dominated by the chemical toxicity of Eu.

Unlocking the potentials of nitrate transporters at improving plant nitrogen use efficiency.

Nitrate ( ) transporters have been identified as the primary targets involved in plant nitrogen (N) uptake, transport, assimilation, and remobilization, all of which are key determinants of nitrogen use efficiency (NUE). However, less attention has been directed toward the influence of plant nutrients and environmental cues on the expression and activities of transporters. To better understand how these transporters function in improving plant NUE, this review critically examined the roles of transporters in N uptake, transport, and distribution processes. It also described their influence on crop productivity and NUE, especially when co-expressed with other transcription factors, and discussed these transporters' functional roles in helping plants cope with adverse environmental conditions. We equally established the possible impacts of transporters on the uptake and utilization efficiency of other plant nutrients while suggesting possible strategic approaches to improving NUE in plants. Understanding the specificity of these determinants is crucial to achieving better N utilization efficiency in crops within a given environment.

Nitrogen fertilizer and tillage intensity affected winter wheat macronutrient uptake and utilization efficiencies

AbstractApplication of N fertilizer and no‐tillage (NT) can increase winter wheat (Triticum aestivum L) production through improvements in plant available soil water and nutrient availability. However, long‐term tillage and N management interaction effects on winter wheat nutrient uptake are not well known. The objective of this study was to quantify winter wheat grain yield, macronutrient removal, and utilization responses to N fertilizer application and tillage intensity. The study was conducted in 2019 and 2020 at Hays, Kansas after 45 years of tillage and N fertility experiment. Treatments were a combination of two tillage practices (CT, conventional tillage; NT) and four rates of N (0, 45, 90, and 134 kg ha−1). Results showed a significant tillage and N fertilizer interaction effect on wheat grain yield, nutrient removal (NR) (grain‐N, ‐P, ‐K, ‐Mg; stover‐K, and total P), and nutrient concentration (stover‐K and ‐S). Two different quadratic models fit the N rate‐to‐yield relation for CT and NT with yields of 4.3 and 5.2 Mg ha−1 at agronomic optimal N rates of 119 and 199 kg N ha−1, respectively. This suggests that the N rates were not high enough to predict optimum N rate for NT in this environment. With an average yield of 3.30 Mg ha−1, wheat removed about 113 kg N ha−1, 17 kg P ha−1, 56 kg K ha−1, 7 kg Ca ha−1, 8 kg Mg ha−1, and 8 kg S ha−1, irrespective of tillage practice. Grain yields and NR were greater for CT at smaller N rates (&lt;90 kg N ha−1) and for NT at greater N rates (&gt;90 kg ha−1). Findings of the study suggest that adequate N fertility (&gt;90 kg ha−1) should be maintained to improve grain yield, nutrient uptake, and utilization efficiency in dryland NT wheat production systems.

Identification of Yield-Limiting Nutrients for Sorghum (Sorghum bicolor (L.) Moench) Yield, Nutrient Uptake and Use Efficiency on Vertisols of Raya Kobo District, Northeastern Ethiopia

Agricultural productivity was negatively impacted by low soil fertility and uneven fertilizer application during crop cultivation in Ethiopia. Because of this, important crops frequently respond to fertilizer applications significantly below their achievable and potential yields. This study was carried out to determine the most sorghum yield-limiting nutrients in the Raya Kobo area of the Amhara Region in the 2020/21 crop season. Sorghum variety Girana-One was used as the test crop. Control, NPS, PSBZn, NPBZn, NSBZn, NPSB, NPSZn, NPSBZn, recommended NP, and NPSKBZn were treatments. Three replications of the experiment were used in a randomized complete block design. Before treatment application, a composite soil sample was collected at a depth of 0–20 cm to determine the soil’s physicochemical properties. To evaluate N and P uptakes, samples of sorghum stalk and grain were collected. SAS software was used to analyze the data. Results showed that, NPKSZnB produced a considerably greater grain yield (4620 kg·ha−1), whereas the control and N omitted plots produced the lowest grain yields (2759 kg·ha−1) and 2805 kg·ha−1, respectively. Nitrogen fertilizer missing plots showed a statistically significant yield drop compared to the other plots, and there was no statistically significant yield difference between the prescribed NP plots and the potassium, sulfur, boron, or zinc omitted plots. The plots treated with NPKSZnB had the highest agronomic efficiency for N (19.7 kg grain kg−1·N) and P (10.6 kg grain kg−1 P2O5). Therefore, research and development should therefore concentrate on nitrogen to achieve the best sorghum yield for the study location. Phosphorus might also be used to keep the fertility level within the ideal range.

Salinity distribution pattern and its induced adaptability of tomato roots

Salinity is a major abiotic stress and threat to tomato production. Roots can attenuate salt stress at a specific salinity concentration, especially with non-uniform salinity distribution conditions, and may play a role in enhancing tomato plant adaptability to salt stress. Salt stress will also have a certain impact on root growth, which in turn affects the adaptability of crops to salt stress. Under different salt gradients, if we can find a reasonable distribution strategy, we can increase the tolerance of plants to salt stress. The hydroponics method was used and the roots were split into left and right parts. We established different salinity distribution patterns: a uniform salinity distribution T1 [0, 0], T2 [0.2%, 0.2%], and T3 [0.3%, 0.3%] and a non-uniform salinity distribution T4 [0.1%, 0.3%], T5 [0.1%, 0.5%], T6 [0.2%, 0.4%]. We observed the whole growth stage, and the plant's physiological responses to salt stress were measured. The data indicated that tomato plant roots can attenuate salt stress at a salinity concentration of 0.4%. The non-uniform salinity distribution can restrict root-uptake and uptake efficiency of nutrients (Na+, K+). Fruit yield, flavor and quality were enhanced by the non-uniform salinity distribution of T4 [0.1%, 0.3%]. Increased K+ led to a decreased Na/K ratio, which could reduce the toxicity of salt ions and improve tomato growth. The antioxidant enzyme activities of both roots and leaves of tomato plants were elevated under different salt stress patterns, indicating that the subject plants have the potential to exert adversity adaptations and that the enzyme activities are responsive to the degree of salt stress. Response of tomato fruiting stage growth and development and yield quality to different salt stresses. Growth adaptation of tomato under salt stress conditions. The above issues are discussed to provide a theoretical basis for the salt tolerance mechanism of tomatoes under non-uniform salt stress and the growth status of tomatoes on saline soils.

Effects of Seed Priming and Foliar Treatment with Ascorbate, Cysteine, and Triacontanol on Canola (Brassica napus L.) under Field Conditions

Studies conducted in controlled environments showed that seed priming and foliar treatments with various bioactive substances can stimulate germination, uniform seedling emergence, photosynthesis, and nutrient uptake efficiency and can lead to increased productivity, crop stand, and quality. Only a few studies provide a comparative experimental outlook about the use of the bioactive substances in open-field cultivated canola. The aim of this study was to investigate the effects of seed priming and foliar treatment with ascorbate (AsA), cysteine (Cys), and triacontanol (Tria) on the growth and yield parameters of two canola cultivars rapeseed cultivars (“Factor” and “Hybrirock”) under open-field conditions for three growing seasons under temperate conditions from Central Transylvania. Plant growth and yield parameters were recorded at different plant development stages: in autumn (early vegetative period), in spring, and at harvest. Not all substances that have undergone laboratory testing were successful in the field. Seed priming with 10 ppm Cys and AsA had beneficial effects on the development of seedlings, whereas their foliar application enhanced the number of silique, seed yield, and the oil content of the studied canola cultivars. The effects of Tria were visible on the biometrics parameters only in autumn and spring, and also on the root parameters, but in some cases, 10 ppm Tria had no effect on plants, or even a negative effect could be observed on important parameters for agriculture such as estimated seed yield, seed yield/plant, and oil content. Optimizing treatment and application by determination of the lowest effective concentration, together with the frequency of treatments and persistence effects are crucial for cost-effectiveness.

Application of milk vetch (Astragalus sinicus L.) with reduced chemical fertilizer improves rice yield and nitrogen, phosphorus, and potassium use efficiency in southern China

Milk vetch (Astragalus sinicus L.; MV) is the most common winter green manure used in rice cropping systems in southern China. The utilization of MV can achieve the dual goals of soil fertilization and increased rice yield. Two long-term field experiments were conducted in Yujiang and Gaoan in Jiangxi Province, a typical double-rice cropping area, to explore the effects of 80 % conventional fertilizer for early rice supplemented with 15.0 (G1F80), 22.5 (G2F80), 30.0 (G3F80), and 37.5 (G4F80) t ha−1 MV on rice yield, soil fertility, nutrient uptake, and nutrient use efficiency. The results showed that, the yield data obtained from the 5-year (Gaoan) and 12-year (Yujiang) long-term experiments demonstrated that compared with conventional fertilization (F100), treatments with MV markedly increased the yield of early and late rice by 2.5–8.8 % and 5.6–10.9 %, respectively, and high rates of MV (G3F80 and G4F80) performed better in grain yields. The nitrogen (N) and potassium (K) uptake of early rice in Gaoan increased by 38.1 and 34.8 kg ha−1, respectively, and the N uptake of late rice in Gaoan and Yujiang increased by 11.7 and 62.6 kg ha−1 in G2F80, respectively, compared to that in F100. Compared with F100, treatments with MV significantly increased phosphorus (P) fertilizer recovery efficiency by 23.1–36.4 %, and the agronomic efficiency of N, P, and K fertilizers increased by 16.1–21.1 %, 13.9–19.6 %, and 15.7–21.4 %, respectively. Partial least squares path model analysis indicated that soil available P was the most important factor affecting the nutrient uptake of rice, and available K was the most important factor affecting fertilizer use efficiency. Our results suggested that 22.5 t ha−1 MV supplemented with 80 % chemical fertilizer is recommended for double-rice cropping sites to improve rice yield and crop uptake and the use efficiency of N, P, and K fertilizers.

Effect of foliar application of varying doses of salicylic acid at different growth stages on growth, quality and nutrient uptake efficiency of French bean (Phaseolus vulgaris L.)

Background: The ubiquitous presence of salicylic (SA) acid in plant systems has been confirmed by many scientists. Salicylic acid is widely distributed throughout the plant and is proposed to affect a number of phyto-physiological activities. As an endogenous plant growth factor or a hormone SA has number of functions including florigenic and thermogenic role, part in plant-pathogen interaction, signal transduction, etc. Method: The present investigation was conducted at the Experimental Farm of the Division of Vegetable Science, SKUAST-K, during Kharif 2020 to find out the effect of foliar spray of varying doses of salicylic acid (SA) applied at different plant growth stages on growth and quality attributes of French bean var. Shalimar French Bean-1. The experiment was laid out in split plot design with twelve treatment combinations and three replications. Result: The investigation revealed that the treatment combination T1D2 (250ppm of SA applied at plant emergence stage) recorded minimum values for days taken to 50 per cent flowering and days taken to pod formation. Moreover, the same treatment combination T1D2 also recorded maximum values for plant height, number of primary branches plant-1, number of leaves plant-1 et al., leaf area and shoot dry weight plant-1. It was further revealed that in the treatment combination T1D2 maximum values of vitamin C content, TSS, protein content, leaf chlorophyll content and pod dry matter content were also recorded, while pod anthocyanin content was maximum in the treatment combination T2D2 (250ppm of SA applied at vegetative stage). The treatment combination T1D2 also significantly enhanced nutrient uptake efficiency of the plants and resulted in lowest values for the available nitrogen, phosphorus and potassium, soil EC and maximum values for organic carbon as compared absolute control. than absolute control D0.

Response of Maize Varieties (Zea mays L.) to the Application of Classic and Stabilized Nitrogen Fertilizers-Nitrogen as a Predictor of Generative Yield.

The study presents the results of a 3-year field trial aimed at assessing the yield and efficiency indicators of nitrogen application in the cultivation of three maize cultivars differing in agronomic and genetic profile. The advantages of the UltraGrain stabilo formulation (NBPT and NPPT) over ammonium nitrate and urea are apparent if a maize cultivar capable of efficient nutrient uptake in the pre-flowering period and effective utilization during the grain filling stage is selected. Therefore, the rational fertilization of maize with urea-based nitrogen fertilizer with a urease inhibitor requires the simultaneous selection of cultivars that are physiologically profiled for efficient nitrogen utilization from this form of fertilizer ("stay-green" cultivar). The interaction of a selective cultivar with a high genetically targeted potential for nitrogen uptake from soil, combined with a targeted selection of nitrogen fertilizer, is important not only in terms of production, but also environmental and economic purposes.

Effect of Different Rate and Time of Application of Slag based Gypsum on Nutrient Use Efficiency, Quality and Yield of Groundnut

Background: Slag based gypsum (SBG) is a value-added product of iron and steel industry. Application of gypsum as source of calcium and sulphur for groundnut cultivation is common practice and mainly applied during peg initiation stage of groundnut. However, its effect is mainly influenced by the type of soil and dissolution of gypsum, which facilitates the yield and quality of groundnut. Hence, field experiments were conducted to know the effect of application of different rates of SBG as basal and split application on soil properties, yield, quality, nutrient use and uptake efficiency of groundnut in acidic soil. Methods: This study contains of seven treatments which includes recommended dose of fertilizer (RDF) with three levels of SBG (375, 500 and 625 kg ha-1) was applied as basal and split and 500 kg natural gypsum (NG) ha-1 was applied as basal dose according to package of practice (POP) of University of Agricultural Sciences, Bangalore by using randomly complete block design (RCBD) at Agricultural Research Station, Balajigapade during kharif 2018 and 2019. Result: The pooled data of two field experiments on groundnut revealed that application of RDF + 625 kg SBG ha-1 as 50% at sowing + 50% at peg initiation stage recorded higher pod (28.01 q ha-1), haulm (54.46 q ha-1), kernel (20.59 q ha-1), protein (89.70 q ha-1) and oil (7.06 q ha-1) yield when compared to other treatments. There was an increase in pod, haulm and oil yield of groundnut by 11.62, 20.59 and 17.99%, respectively with the split application of 625 kg SBG ha-1 (50% at sowing + 50% at 30 DAS) over NG applied treatments. Split application of SBG significantly increased the availability of nutrients in post harvest soils than basal application. Significantly higher S and Ca nutrient use efficiency (33.98 and 28.93 kg produce/kg S and Ca utilized, respectively) and uptake efficiency (0.39 and 1.29 kg kg-1, respectively) was recorded with the split application of SBG @ 375 kg ha-1.

Differences in Nutrient Uptake Can Influence the Performance of Citrus Rootstocks under Huanglongbing Conditions

Huanglongbing {HLB [Candidatus Liberibacter asiaticus (C Las)]} has been one of the biggest challenges in citrus (Citrus sp.) production in Florida and wherever it is present. HLB-affected trees show significant shoot and root dieback, fruit drop, and reduction in yield. Currently, there is no cure for HLB, and there is no commercial HLB-resistant germplasm. Nonetheless, intensive nutrient management has been promising for citrus growers. The nutrient requirement of HLB-affected trees seems to be greater than that of healthy citrus trees. By understanding the nutrient uptake potential of rootstocks, fertilizer programs can be customized accordingly to enhance the performance of a rootstock in existing groves. Moreover, a reduction in the application of nutrients is possible by planting rootstocks with a high nutrient absorption capacity. Use of rootstocks with good nutrient uptake efficiency can take some burden off the growers who are intensively managing HLB-affected citrus groves. Therefore, the objective of this study was to evaluate and understand the nutrient uptake potential of the citrus rootstocks. To achieve this objective, a 100% hydroponic greenhouse study was conducted with six rootstocks with a range of tolerance to HLB. Several physiological and molecular tools were applied to evaluate the rootstocks for their nutrient uptake potential. A+Volk × O-19 (HLB-tolerant) rootstock had greater nutrient uptake efficiency, whereas US-896 (HLB-susceptible) had lesser nutrient uptake efficiency. Swingle, one of the most popular pre-HLB rootstocks, had poor zinc uptake and the least expression of ZINC TRANSPORTER, suggesting that zinc applications should be emphasized in Swingle plantings. US-896 rootstock expressed the least level of nutrient transporter genes, such as IRON TRANSPORTER. UFR-4 (a good performer under HLB conditions) had a large root biomass, but the uptake efficiency for nutrients was poor, suggesting that the nutrient uptake potential is a complex process that is not solely dependent on root biomass. This study is unique because it is one of the first citrus studies to report nutrient uptake efficiency and the potential of rootstocks. The information presented can be used to improve performance or select better-performing rootstocks under HLB conditions.

Influence of nano nitrogen and nano zinc fertilizers on nutrient uptake and use efficiency in paddy under different systems of establishment

Field experiment on “Influence of nano nitrogen and nano zinc fertilizers on nutrient uptake and Use efficiency in paddy under different systems of establishment”. Randomised complete block design (RCBD) College of Agriculture, Vishweshwaraiah Canal Farm, Mandya, Karnataka, during summer 2022. The study included 14 treatments with various concentrations and sources of nitrogen with nano nitrogen and nano zinc under various establishment methods, including transplanted paddy and system of rice cultivation (SRI), as well as various methods of applying nano fertilisers, such as seed treatment, root dipping, and foliar spray. The results indicated that significantly higher nitrogen uptake (94.42, 79.10 and 173.52 kg ha-1, respectively), phosphorous, potassium uptake and higher nitrogen, phosphorous and potassium use efficiency (58.76, 105.01 and 73.51 kg kg-1 nutrients applied, respectively) was obtained with the application of 75% N and two foliar sprays of nano nitrogen and nano zinc at 25 to 30 and 45 to 50 DAT under SRI method of establishment. SRI method of rice establishment and nano nutrient application will significantly increase the primary, secondary and micro nutrient uptake

Zeoponic, a plant growing medium from zeolite mineral

A plant-growing medium is an essential part of many horticultural crop systems and it influences nutrient uptakes. The present work aims at assessing the beneficial effects of zeoponic, a plant-growing medium made from zeolite, compost, and cocopeat, on the performances of three vegetable crops: green mustard, tomato, and eggplant plants. This research was conducted at IPB greenhouse in Cikabayan and Laboratory of the Department of Soil Science, IPB University, using five different plant growing media, including zeoponic. The plant-growing media and the plant tissues were analyzed to determine the relationship between the plant growing media characteristics and plant growth. According to the findings, zeoponic treatment increased the plant height, root length and shoot fresh weight. Zeoponic increased the efficiency of nutrient uptake, especially nitrogen, due to its great capacity for cation exchange and capacity to absorb ammonium ions. Zeoponic can also maintain low electrical conductivity so that plants cultivate in zeoponic grow faster than those in other plant-growing media.

Biostimulants: An Eco-friendly Approach in Reducing Heavy Metal Toxicity

One of the most serious issues in the nation is heavy metal toxicity. It severely affects both plant and animal kingdom as well as disrupts the soil ecosystem. The consequence of heavy metal toxicity is the generation of osmotic and oxidative stress, membrane dysfunctioning, metabolic imbalances and cellular toxicity. To combat the prevailing issue, seeking eco-friendly ways to enhance and stimulate plant tolerance against stress, is the vital step. Hence, the application of biostimulants can be the best and effective alternative. Biostimulant is a non nutrient preparation of microorganism and/ or substances which enhance the crop quality enrich nutrient uptake efficiency and show tolerance against abiotic stresses. The super dynamic substances utilized in such arrangements are humic and fulvic acids, compounds containing nitrogen, protein hydrolysates, silicon, melatonin, seaweed extracts, and valuable microorganisms. The review briefly articulates the definition of biostimulants, its various types as well as its role towards reducing the heavy metal toxicity. Apart from these, the review also takes in consideration the ameliorating effects of silicon against heavy metal toxicity. Hence, biostimulants play an important role as reactive oxygen scavengers, stimulate antioxidant system of the plant, and induce gene expression of stress responsive gene thereby fostering plant tolerance to heavy metal toxicity.

Sugarcane straw management by inoculation of microbial consortia and its impact on short-term N source and amelioration of ratoon sugarcane yield

ABSTRACT The objectives of this study was to assess the effect of the inoculation of sugarcane straw with an artificial microbial consortium (MC) on soil mineral N, soil organic matter (SOM), sugarcane straw decomposition, hydrolytic enzyme activities (β-glucosidase, urease), oxidative enzyme activities (phenoloxidase, peroxidase), nutrient uptake and ratoon cane yield. The experiment consisted of two field experiments, i.e. the experiment I field was sandy soil, and the experiment II field was sandy loam soil in Khon Kaen Province. After planted cane harvest, there were three treatments, namely, burn (B), incorporation (I) and I+ MC treatments. Experiment II consisted of three treatments, namely, B, mulch (M) and M+ MC treatments. Sugarcane straw was applied at a rate of 6.25 tons ha−1. The results revealed that sugarcane straw management by inoculation of microbial consortia had a higher soil mineral N content than that of other treatments, improved the straw decomposition, hydrolytic and oxidative enzyme activities, SOM accumulation (7.60, 20.58 g kg−1 respectively), yield (49.47, 131.51 ton ha−1 respectively), nutrient uptake and nutrient use efficiency of ratoon cane. Thus, sugarcane straw management by inoculation of microbial consortia becomes a short-term N source and a potential application to enhance decomposition leading to increased ratoon cane yield.

Sustainable Application for Agriculture Using Biochar-Based Slow-Release Fertilizers: A Review

The continuous increase in the world population, combined with the rapid degradation of arable land, has put a strain on agricultural production. The excessive use of conventional fertilizers leads to environmental issues associated with the loss of nutrients through leaching, volatilization, denitrification, and surface runoff. Biochar-based slow-release fertilizers (BSRFs) derived from biomass waste could effectively alleviate environmental issues by improving soil properties, slowing nutrient release, and enhancing plant nutrient uptake efficiency. The goal of this review is to outline current progress in the agricultural application of BSRFs. The properties and construction of BSRFs were described. The raw materials source, preparation conditions, and slow-release mechanisms of BSRFs were introduced in detail. Nutrient composition and physicochemical properties of BSRFs could be selectively given, which provides a basis for practical agricultural application. Based on the evaluation of technical, economic, environmental, and political factors of BSRFs, it is proposed to apply BSRFs to agriculture and other fields such as urban parks and gardens.

Strigolactones in Plants and Their Interaction with the Ecological Microbiome in Response to Abiotic Stress.

Phytohormones play an essential role in enhancing plant tolerance by responding to abiotic stresses, such as nutrient deficiency, drought, high temperature, and light stress. Strigolactones (SLs) are carotenoid derivatives that occur naturally in plants and are defined as novel phytohormones that regulate plant metabolism, growth, and development. Strigolactone assists plants in the acquisition of defensive characteristics against drought stress by initiating physiological responses and mediating the interaction with soil microorganisms. Nutrient deficiency is an important abiotic stress factor, hence, plants perform many strategies to survive against nutrient deficiency, such as enhancing the efficiency of nutrient uptake and forming beneficial relationships with microorganisms. Strigolactone attracts various microorganisms and provides the roots with essential elements, including nitrogen and phosphorus. Among these advantageous microorganisms are arbuscular mycorrhiza fungi (AMF), which regulate plant metabolic activities through phosphorus providing in roots. Bacterial nodulations are also nitrogen-fixing microorganisms found in plant roots. This symbiotic relationship is maintained as the plant provides organic molecules, produced in the leaves, that the bacteria could otherwise not independently generate. Related stresses, such as light stress and high-temperature stress, could be affected directly or indirectly by strigolactone. However, the messengers of these processes are unknown. The most prominent connector messengers have been identified upon the discovery of SLs and the understanding of their hormonal effect. In addition to attracting microorganisms, these groups of phytohormones affect photosynthesis, bridge other phytohormones, induce metabolic compounds. In this article, we highlighted the brief information available on SLs as a phytohormone group regarding their common related effects. In addition, we reviewed the status and described the application of SLs and plant response to abiotic stresses. This allowed us to comprehend plants' communication with the ecological microbiome as well as the strategies plants use to survive under various stresses. Furthermore, we identify and classify the SLs that play a role in stress resistance since many ecological microbiomes are unexplained.

Regulation of Bacterial Behavior by Light and Magnetism Mediated by Mesoporous Silica-Coated MnFe2O4@CoFe2O4 Nanoparticles

Unicellular bacterial cells exhibit diverse population behaviors (i.e., aggregation, dispersion, directed assembly, biofilm formation, etc.) to facilitate communication and cooperation. Suitable bacterial behaviors are required for efficient nutrient uptake, cell recycling, and stress response for environmental and industrial application of bacterial populations. However, it remains a great challenge to artificially control bacterial behaviors because of complicated genetic and biochemical mechanisms. In this study, we designed facile mesoporous silica nanoparticle (MSN)-based assemblies to intelligently regulate bacterial behaviors with the help of light and magnetic field. This system was composed of magnetic MSNs, i.e., MnFe2O4@CoFe2O4@MSN modified by photoactive spiropyran (SP), and the chitosan-based polymers ChiPSP, i.e., chitosan grafted by triphenylphosphine and SP. The assembly strongly bound bacterial cells, inducing reversible bacterial aggregation by visible-light irradiation and dark. Moreover, the formed bacterial aggregates could be further governed by a directed magnetic field (DMF) to form microfibers and by an alternating magnetic field (AMF) to form biofilms. This study realized stimulus-triggered regulation of bacterial behaviors by MSNs and implied the great power of chemical strategies in intelligent control of diverse biological processes for environmental and industrial applications.

Phosphorus availability mediates plant–plant interaction and field productivity in maize-grass pea intercropping system: Field experiment and its global validation

CONTEXTPlant–plant competitive and facilitative interactions might strongly affect the biodiversity effect and field productivity of intercropping system under the condition of limited resources such as available phosphorus (P). To test this hypothesis, the maize–grass pea intercropping system with five P application gradients (from low- to high-P) was experimentally investigated and the global meta-analysis validation was simultaneously performed. OBJECTIVEThe main objectives of this study included as: 1) to examine the characteristics of plant–plant interaction variations along soil P addition gradients; 2) to identify the shift from interspecific complementarity to selection effect regarding the productivity and nutrient uptake and its driving mechanism; 3) to verify the universality of above phenomenon via global meta-analysis and explore the general pattern of P-dependent plant–plant interactions in the intercropping systems. RESULTS AND CONCLUSIONSRegardless of growing seasons, the total net effect of intercropping system was always >0, showing net facilitative effects of plant–plant interactions on field productivity and nutrient uptake efficiency, relative to monoculture systems. On average, the yield, biomass, N and P uptake were elevated by 3.0–13.7%, 3.2–12.8%, 7.5–20.1% and 5.6–18.9% in intercropping respectively, relative to those of monoculture. On the other hand, the contribution of complementarity effect to the total net effect was up to 78.7%, much more than that of selection effect (21.3%). The relative interaction index tended to decline remarkably with increasing soil P availability (from 0.097–0.126 to 0.027–0.029), suggesting that the facilitation (rather than the competition) dominated in intercropping under the low-P condition. Furthermore, the intercropped grass pea decreased the harvest index and allocated more biomass to vegetative growth as a result of the enhanced interspecific competition under the P-sufficient condition. Finally, the meta-analysis demonstrated that intercropping system had greater relative benefits regarding field productivity and N/P acquisition and utilization than monoculture system. In the meanwhile, the intensity of interspecific facilitative effect was enhanced under the P-deficient condition. SIGNIFICANCEField observations presented the evidences regarding the P-dependent plant-plant interactions and its effects on field productivity in the maize-grass pea intercropping system. The meta-analysis confirmed that high P application decreased the interspecific facilitative effects in terms of field productivity and nutrient utilization in the intercropping systems. But the low-P condition led to the opposite trend, i.e. facilitative effect dominated in the intercropping for greater productivity efficiency.

Aerated drip irrigation improves water and nitrogen uptake efficiencies of tomato roots with associated changes in the antioxidant system

• After aerated drip irrigation, soil oxygen content significantly increased. • The duration and sequence of aeration changed the root antioxidant system. • The root antioxidant system correlated root morphology of tomato. • Root antioxidant systems and growth affect water and nitrogen uptake efficiency of tomato. China has the largest area of vegetable cultivation in greenhouse vegetable system in the world. However, the excessive application of irrigation and fertilizers has caused soil degradation and hardening, even leading to injury and yield loss in vegetable. Increasing soil aeration oxygen can improve crop water and nutrient uptake efficiencies. However, its effects on crop antioxidant systems are less known. Due to the sensitivity of the antioxidant system to changes in soil oxygen content, it is expected that aerated drip irrigation (ADI) delivering microbubble water to the crop rhizosphere will alter root antioxidant enzyme activities, malondialdehyde (MDA) content, and osmotic regulators in tomato plants. We conducted pot experiments under eight irrigation regimes: five aerated durations (0%, 25%, 50%, 75%, and 100%) of the subsurface drip irrigation period aerated (CK, A 25% , A 50% , A 75% , and A), with two aerated sequences (L: subsurface drip irrigation follow by aerated drip irrigation, F: aerated drip irrigation follow by subsurface drip irrigation) for the A 25% , A 50% and A 75% treatments. All treatments with ADI had an average of 7.63% higher oxygen concentration (OC) than the CK treatment at 74 d after transplanting. The principal component analysis revealed that MDA of all treatments had the greatest effect on the antioxidant system, while aerated drip irrigation reduced MDA content. Increasing aeration duration from A 25% to A 75% significantly affected antioxidant enzyme activities and root growth parameters, and the L treatment had higher values than the F treatment. The L -A 75% treatment had the highest water use efficiency, nitrogen uptake efficiency, and yield. The structural equation model demonstrated that ADI indirectly promotes tomato water and nitrogen uptake efficiencies by affecting the antioxidant system and root growth.