Nutrient Uptake Efficiency Research Articles

Transcriptome profiles of rice roots under simulated microgravity conditions and following gravistimulation.

Root system architecture affects the efficient uptake of water and nutrients in plants. The root growth angle, which is a critical component in determining root system architecture, is affected by root gravitropism; however, the mechanism of root gravitropism in rice remains largely unknown. In this study, we conducted a time-course transcriptome analysis of rice roots under conditions of simulated microgravity using a three-dimensional clinostat and following gravistimulation to detect candidate genes associated with the gravitropic response. We found that HEAT SHOCK PROTEIN (HSP) genes, which are involved in the regulation of auxin transport, were preferentially up-regulated during simulated microgravity conditions and rapidly down-regulated by gravistimulation. We also found that the transcription factor HEAT STRESS TRANSCRIPTION FACTOR A2s (HSFA2s) and HSFB2s, showed the similar expression patterns with the HSPs. A co-expression network analysis and an in silico motif search within the upstream regions of the co-expressed genes revealed possible transcriptional control of HSPs by HSFs. Because HSFA2s are transcriptional activators, whereas HSFB2s are transcriptional repressors, the results suggest that the gene regulatory networks governed by HSFs modulate the gravitropic response through transcriptional control of HSPs in rice roots.

Nanofertilizers: The Next Generation of Agrochemicals for Long-Term Impact on Sustainability in Farming Systems

The microflora of the soil is adversely affected by chemical fertilizers. Excessive use of chemical fertilizers has increased crop yield dramatically at the cost of soil vigor. The pH of the soil is temporarily changed by chemical fertilizers, which kill the beneficial soil microflora and can cause absorption stress on crop plants. This leads to higher dosages during the application, causing groundwater leaching and environmental toxicity. Nanofertilizers (NFs) reduce the quantity of fertilizer needed in agriculture, enhance nutrient uptake efficiency, and decrease fertilizer loss due to runoff and leaching. Moreover, NFs can be used for soil or foliar applications and have shown promising results in a variety of plant species. The main constituents of nanomaterials are micro- and macronutrient precursors and their properties at the nanoscale. Innovative approaches to their application as a growth promoter for crops, their modes of application, and the mechanism of absorption in plant tissues are reviewed in this article. In addition, the review analyzes potential shortcomings and future considerations for the commercial agricultural application of NFs.

Biostimulant effects on the herbage yield and nutritive composition of a mixed ryegrass–clover pasture

Dairy producers are continuously searching for environmentally friendly and economically sustainable alternatives to increase pasture herbage yield and reduce reliance on chemical fertilisers. A possible means to reduce fertiliser reliance is the use of biostimulants. Biostimulants such as fulvic acid and bioflavonoids help to increase N uptake efficiency, thereby increasing herbage quantity and quality. The aim of this study was to determine the effects of a soil application of a carbohydrate-derived fulvic acid and bioflavonoid biostimulant on herbage yield and nutritive composition of a mixed perennial ryegrass–clover pasture. Biostimulant treatment resulted in a lower ryegrass component of the mixed sward, in both winter and summer grazing cycles. However, the nutritive composition and total herbage yield of the pasture were not significantly affected by biostimulant treatment. The treatment did show a tendency to affect total herbage yield within a season. This suggests that total herbage yield could be increased if additional N fertiliser is applied together with a biostimulant soil treatment, although further investigation is needed to confirm this postulation. Biostimulant treatments have the potential to lead to reduced fertiliser inputs on perennial ryegrass–clover pastures as they may increase nutrient uptake efficiency.

Experimental and theoretical investigations of rotating algae biofilm reactors (RABRs): Areal productivity, nutrient recovery, and energy efficiency.

Microalgae biofilms have been demonstrated to recover nutrients from wastewater and serve as biomass feedstock for bioproducts. However, there is a need to develop a platform to quantitatively describe microalgae biofilm production, which can provide guidance and insights for improving biomass areal productivity and nutrient uptake efficiency. This paper proposes a unified experimental and theoretical framework to investigate algae biofilm growth on a rotating algae biofilm reactor (RABR). Experimental laboratory setups are used to conduct controlled experiments on testing environmental and operational factors for RABRs. We propose a differential-integral equation-based mathematical model for microalgae biofilm cultivation guided by laboratory experimental findings. The predictive mathematical model development is coordinated with laboratory experiments of biofilm areal productivity associated with ammonia and inorganic phosphorus uptake by RABRs. The unified experimental and theoretical tool is used to investigate the effects of RABR rotating velocity, duty cycle (DC), and light intensity on algae biofilm growth, areal productivity, nutrient uptake efficiency, and energy efficiency in wastewater treatment. Our framework indicates that maintaining a reasonable light intensity range improves biomass areal productivity and nutrient uptake efficiency. Our framework also indicates that faster RABR rotation benefits biomass areal productivity. However, maximizing the nutrient uptake efficiency requires a reasonably low RABR rotating speed. Energy efficiency is strongly correlated with RABR rotating speed and DC.

Soil Nutrient, Salinity, and Alkalinity Responses of Dendrocalamopsis oldhami in High-Latitude Greenhouses Depending on Planting Year and Nitrogen Application

This study explored the viability of greenhouse cultivation of Dendrocalamopsis oldhami under the “South Bamboo North Transplanting” initiative. In this study, the effects of planting year and nitrogen application on changes in soil nutrient levels, salinity, and alkalinity over the plant growth period were explored. After the introduction and planting of bamboo in 2017, a soil layer with a thickness of 0–40 cm was sampled at the end of the shooting stage in the greenhouse between 2017 and 2019 (late August), and the bamboo shoot yield and standing culm density were measured. Following the application of nitrogen to the bamboo groves in 2019, three nitrogen levels were established: no nitrogen (N1:0 g grove−1), medium nitrogen (N2:540 g grove−1), and high nitrogen (N3:1080 g grove−1). Soil layers at depths of 0–20 and 20–40 cm were sampled during the shoot elongation stage (late May) and at the end of the shooting stage (late August). The yield and nutrient content of bamboo shoots under different nitrogen treatments were also investigated. The results showed that Ca2+ and HCO3− were the main salt ions in greenhouse soil. With later planting years, the total number of cations (Ca2+, Na+, Mg2+, and K+) decreased, whereas the total number of anions (HCO3−, SO42−, NO3−, and Cl−) increased, resulting in a decrease in the percentage of exchangeable sodium (ESP), pH, and electrical conductivity (EC). The diameter at breast height, individual weight, and quantity of bamboo shoots increased annually, and the standing culm density increased by 1.4 times. Each year, the total nitrogen content decreased, whereas the alkali-hydrolyzed nitrogen, available phosphorus, and available potassium contents increased. Nitrogen application resulted in a significant decrease in ESP and pH and an increase in the total anion, cation, and EC values. It also reduced soil organic carbon, total nitrogen, total phosphorus, total potassium, available phosphorus, and available potassium. Nitrogen application increased the number of bamboo shoots, total yield, and accumulation of N and P; however, there was no significant difference between N2 and N3. In conclusion, the salinization of calcareous soil was alleviated, and the available nutrients were activated following the introduction of D. oldhami from south to north. The mineralization rates of organic matter and soil fertility increased. Soil acidification and EC decreased at the end of the shoot stage. Nitrogen application acidified the soil, and the yield and soil salt accumulation increased with increasing nitrogen levels. The nutrient uptake efficiencies of nutrients at high nitrogen levels were lower than those at medium nitrogen levels. Therefore, soil salt concentrations with values 0.26 < EC < 0.42 hindered the nutrient uptake of D. oldhami.

Stoichiometric Characteristics of Abies georgei var. smithii Plants in Southeast Tibet

In order to elucidate the adaptation mechanisms of the stoichiometric characteristics of Abies georgei var. smithii in southeastern Tibet to different habitats, the spatial and temporal dynamics of the nutrient contents and stoichiometric ratios among the leaf, branch, stem, and root organs were analyzed on Sejila Mountain in southeastern Tibet at different elevations (3500 m, 3900 m, and 4300 m). The results show that (1) the C and K contents of the fir organs did not change significantly with increasing elevation in the same season, while the N and P contents showed an overall increasing trend with increasing elevation, with the C and N contents being the highest in the leaves. The distribution order was leaves > branches > roots > stem; the P and K content order in each organ was branches > leaves > roots > stem. (2) At the same elevation and in different seasons, the Abies georgei var. smithii organs showed a similar convergence in terms of nutrient storage and utilization strategies, and more nutrients were optimally allocated between the assimilated and stored organs in the alpine habitats, which represents a “trade-off” strategy. (3) Compared to the findings of the global-scale studies, this study area has low N, P, and K contents, and its growth is limited by both N and P. Due to physiological and nutrient balance constraints, the content of the N-limited elements in the plants is relatively stable, which is in line with the “limiting element stability hypothesis”. (4) Principal component analysis showed that the influence of environmental factors on the stoichiometric characteristics of the different organs of Abies georgei var. smithii had a spatial scale effect, and that Abies georgei var. smithii demonstrated increased accumulation of N and P contents when subjected to environmental stress, which promoted the domestication and adaptation of the plant, enabling it to show good nutrient accumulation capacity and good adaptation strategies even at high elevation; thus, it has become a pioneer tree species at high elevations. This research work shows that the resilient adaptation of Abies georgei var. smithiir to environmental change has led to differences in the nutrient uptake and use efficiency and the adaptation patterns of the organs at different altitudinal gradients, with each organ adapting to habitat changes by adjusting its nutrient storage strategy between habitats.

Influence of Variable Chloride/Sulfur Doses as Part of Potassium Fertilization on Nitrogen Use Efficiency by Coffee.

Chloride (Cl-) is applied in coffee at rates as a "macronutrient" in the form of muriate of potash (MOP). Potassium (K+) is one of the most demanded nutrients by the coffee plant, and MOP is one of the most used fertilizers in coffee production. No scientific evidence shows how Cl- applied with MOP influences coffee growth, nutrient uptake, and nitrogen use efficiency (NUE). In order to address these questions, a greenhouse trial over two years and a field trial over four years were conducted. The trials were designed to test the influence of variable Cl-/S ratios on biomass accumulation, nutrient uptake, and NUE. A significant effect of the Cl- rates on growth was observed under greenhouse conditions but a non-significant effect on yield under field conditions. Cl- and S significantly influenced the NUE in coffee. The results allow us to conclude that Cl- rates need to be balanced with S rates, and that Cl- applied at macronutrient rates can improve the NUE in coffee between 7 and 21% in greenhouse conditions and between 9% and 14% in field conditions, as long as the rates do not exceed 180 mg L-1 Cl- and 80 mg·L-1 S in the greenhouse and 150 kg·ha-1·year-1 Cl- and 50 kg ha-1·year-1 S in the field. With the aim to improve the NUE in coffee, the Cl- content in leaves in coffee should be lower than 0.33% of dry matter, and in soil lower than 30 mg·L-1. In practical terms, coffee farmers need to balance K-based fertilizers to avoid the excessive Cl- applications that reduce the nutrient use efficiency, especially the NUE.

Fine root and soil nutrients pool in the ecosystem following two scenarios of reconstruction—post‐fire and post‐mining large‐scale disturbance

AbstractThis study compares the concentration and quantitative ratios of macronutrients (nitrogen, phosphorus, magnesium, and potassium) in the litter and fine roots of various species stands, comprising Scots pine, Common birch, and European larch, in the context of nutrient pool formation and nutrient uptake efficiency in various regeneration scenarios and the reconstruction of forest ecosystems. The control plots were located on podzols in the natural habitats. The performed experiments showed that in all species scenarios, the nitrogen pool supplied to the soil with fine roots was equivalent to the pool supplied with the leaves; furthermore, in the case of phosphorus, the pool was even higher than the one reaching the soil through under‐canopy litterfall. However, the total amount of nutrients supplied to the soil by the birch, larch, and pine in different afforestation scenarios varied. Scots pine was the species that supplied the largest amounts of nitrogen and phosphorus in the reconstructed forest ecosystems, while birch was the species that provided the largest amounts of total nitrogen and phosphorus in the regenerated and control forest ecosystems.

Nitrogen Uptake Efficiency: A Measurement for Improving Nutrient Management in Wheat

AbstractNutrient management, and more specifically nitrogen management, is important for the bottom line and is an integral part of soil health. Conducting a post‐harvest assessment of yield, grain protein levels, and nutrient uptake efficiency is a vital part of an effective nutrient management plan. This article demonstrates the use of a tool to do this. Earn 0.5 CEUs in Nutrient Management by reading this article and taking the quiz at https://web.sciencesocieties.org/Learning‐Center/Courses.

Arbuscular mycorrhizas amplify the risk of heavy metal transfer to human food chain from fly ash ameliorated agricultural soils

Soil contaminants threaten global food security by posing threats to food safety through food chain pollution. Fly ash is a potential agent of soil contamination that contains heavy metals and hazardous pollutants. However, being rich in macro- and micronutrients that have direct beneficial effects on plant growth, fly ash has been recommended as a low-cost soil ameliorant in agriculture in countries of the Global South. Arbuscular mycorrhizal fungi (AMF), ubiquitous in agricultural soils, enhance efficiency of plant nutrient uptake from soils but can equally increase uptake of toxic pollutants from fly ash ameliorated soils to edible crop tissues. We investigated AMF-mediated amplification of nutrient and heavy metal uptake from fly ash amended soils to shoots, roots and grains of barley. We used a microcosm-based experiment to analyse the impacts of fly ash amendments to soil in concentrations of 0 (control), 15, 30 or 50% respectively, on root colonization by AMF Rhizophagus irregularis and AMF-mediated transfer of N, P and heavy metals: Ni, Co, Pb and Cr to barley tissues. These concentrations of fly ash are equivalent to 0, 137, 275 and 458 t ha−1 respectively, in soil. Root AMF colonization correlated negatively with fly ash concentration and was not detected at 50% fly ash amendment. Shoots, roots and grains of mycorrhizal barley grown with 15, 30 and 50% fly ash amendments had significantly higher concentrations of Ni, Co, Pb and Cr compared to the control and their respective non-mycorrhizal counterparts. Presence of heavy metals in barley plants grown with fly ash amended soil and their increased AMF-mediated translocation to edible grains may significantly enhance the volume of heavy metals entering the human food chain. We recommend careful assessment of manipulation of agricultural soils with fly ash as heavy metal accumulation in agricultural soils and human tissues may cause irreversible damage.

Soil substrate source drives the microbes involved in the degradation of gelatin used as a biostimulant

Plant biostimulants improve crop yield and quality by stimulating plant nutrition processes and enhancing nutrient uptake efficiency, likely reflecting indirect effects mediated by beneficial soil microbes. Gelatin is an emerging plant biostimulant. Culture-dependent studies have identified several species of gelatin-degrading microbes, but the effect of gelatin on soil microbial communities in the absence of the plant microbiome has not been investigated. The objectives of this work were to evaluate changes in the microbial community induced by granulated gelatin amendments in different soils and substrates using high-throughput sequencing and to identify gelatin-hydrolyzing microbes for further application. Sandy soil, potting soil, paper plugs, black peat soil and pH-neutralized black peat soil were amended with gelatin and incubated at room temperature. After 7 and 15 days, samples were collected, DNA was extracted, and the bacterial and fungal communities were assessed by high-throughput sequencing of the 16S rRNA gene and the internal transcribed spacer (ITS) region, respectively. In parallel, microbes were isolated in culture medium. Regression analysis of shifts in the microbial communities demonstrated that the microbes positively impacted by gelatin amendment varied among the substrates, whereas few variations occurred between timepoints. The fungal genera Penicillium, Mortierella, Fusarium and Trichoderma and the bacterial genera Burkholderia, Pseudomonas and Rhodanobacter were among the microbes that increased in relative abundance in response to gelatin amendment. These microbes are efficient enzyme producers and are potential candidates for formulating beneficial microbial consortia that can be applied in tandem with gelatin to enhance its biostimulant activity.

Moving towards Gel for Fish Feeding: Focus on Functional Properties and Its Acceptance.

To resurrect and establish a low-impact aquaculture practice, gel-based feed applications hold promise. Gel feed is viscoelastic, nutrient-dense, hard, flexible, and appealing, and can be moulded into appealing shapes to ensure rapid acceptance by fish. The purpose of this research is to create a suitable gel feed using various gelling agents and to evaluate its properties and acceptance by a model fish, Pethia conchonius (rosy barb). Three gelling agents, viz. starch, calcium lactate and pectin, were included at 2%, 5%, and 8% in a fish-muscle-based diet. The physical properties of gel feed were standardized using texture profile analysis, sinking velocity, water and gel stability, water holding capacity, proximate composition, and colour. The lowest levels of nutrient leaching protein (0.57 ± 0.15%) and lipid (14.3 ± 14.30%) were observed up to 24 h in the underwater column. The highest score for overall physical and acceptance characteristics was noted for the 5% calcium lactate-based gel feed. Furthermore, a 20-day acceptance feeding experiment was conducted using 5% calcium lactate to examine its suitability as fish feed. The results indicate a better acceptability (3.55 ± 0.19%) and water stability (-2.5 ± 2.5%) of the gel feed compared to the control, with an improvement in nutrient losses. Overall, the study provides an insight into the application of gel-based diets for ornamental fish rearing, besides ensuring an efficient nutrient uptake and minimal leaching to establish a clean aquatic environment.

Assessment of Agronomic Zinc Biofortification of Alley Cropped Pearl Millet

The availability of nitrogen (N) and zinc (Zn) at the specific plant growth stage is crucial for attaining the higher nutrient use efficiency (NUE) and uptake. An experiment was conducted, having 4-N scheduling [No N; ½[basal]+ ½[3rd visible leaf (VL)]; ¼[basal]+ ½[3rdVL]+ ¼[panicle extended in flag leaf sheath (PEFLS)]; ½[basal] + ¼[3rdVL]+ ¼[panicle visible (PV)], and 4-Zn scheduling [No Zn; 2.5 kg/ha [basal]+ 0.25% spray(*) [panicle initiation (PI)]; 2.5 kg/ha [basal]+0.25% [PI]*+ 0.25% [PEFLS]*; 2.5 kg/ha [basal]+ 0.25% [50% panicle emergence (PE)]*+ 0.25% [milk stage (MS)]*. Nitrogen schedule at ¼[basal]+ ½[3rdVL]+ ¼[PEFLS] recorded the maximum nutrient content, uptake, and NUE. Similarly, the maximum nutrient content, uptake, and nutrient use efficiency observed in the Zn at 2.5 kg/ha [basal]+0.25% [PI]*+ 0.25% [PEFLS]*. Moreover, N and Zn interacted significantly to increase the grain N and Zn content and uptake by grain.
 Bangladesh J. Bot. 52(1): 203-209, 2023 (March)

Environmentally friendly bioameliorant to increase soil fertility and rice (Oryza sativa) production

Abstract Soil nutrients can be reduced because of global climate change. This is because climate change causes high rainfall intensity and a prolonged dry season. Efforts to overcome this are fertilized using bioameliorants so that soil nutrients remain available for plants. Observations have been made from May to August 2018 at the JAMTANI Field Laboratory. The study used a factorial randomized block design with three replications. The first factor was a bioameliorant (P1 = goat manure 10 tons ha−1; P2 = goat manure 10 tons ha−1 + Azolla pinnata 10 tons ha−1; P3 = goat manure 10 tons ha−1 + Sesbania rostrata 2 tons ha−1; dan P4 = goat manure 10 tons ha−1 + A. pinnata 5 tons ha−1 + S. rostrata 1 tons ha−1) and the second factor was rice varieties (Ciherang and Mendawak). The application of bioameliorant increased C-organic of soil by 9.04% to 20.41% and soil nitrogen by 11.76% to 38.24%. The addition of bioameliorant did not cause differences in the weight of the plant between the Mendawak variety (61.34 g) and the Ciherang variety (56.96 g). The most efficient addition of bioameliorant is P3 (goat manure 10 tons ha−1 + S. rostrata 2 tons ha−1) with nutrient uptake efficiency value reaching 5.77%. The use of bioameliorant is expected to be able to substitute the use of inorganic fertilizers and increase rice production.

Advances in electrochemically active biofilm of Shewanella oneidensis MR-1

Facing the increasingly severe energy shortage and environmental pollution, electrocatalytic processes using electroactive microorganisms provide a new alternative for achieving environmental-friendly production. Because of its unique respiratory mode and electron transfer ability, Shewanella oneidensis MR-1 has been widely used in the fields of microbial fuel cell, bioelectrosynthesis of value-added chemicals, metal waste treatment and environmental remediation system. The electrochemically active biofilm of S. oneidensis MR-1 is an excellent carrier for transferring the electrons of the electroactive microorganisms. The formation of electrochemically active biofilm is a dynamic and complex process, which is affected by many factors, such as electrode materials, culture conditions, strains and their metabolism. The electrochemically active biofilm plays a very important role in enhancing bacterial environmental stress resistance, improving nutrient uptake and electron transfer efficiency. This paper reviewed the formation process, influencing factors and applications of S. oneidensis MR-1 biofilm in bio-energy, bioremediation and biosensing, with the aim to facilitate and expand its further application.

Effect of light spectra on stem cutting rooting and lavender growth

French lavender (Lavandula dentata L.) is of great ornamental, medicinal, and aromatic interest. It is generally propagated vegetatively using stem cuttings. When using artificial lighting, a specific light composition can modify the entire plant phenology and is a factor that can be managed in controlled conditions. This study evaluated the rooting of stem cuttings and growth of lavender under four spectral LED lights. The LED lights used were: T0 (white LED, Roblan®), T1 (AP67 Milky, Valoya®), T2 (NS1, Valoya®), and T3 (AP673L Milky, Valoya®). The first phase evaluated the rooting of stem cuttings and initial development. The plants were then transferred to plastic pots to evaluate plant growth. In both rooting and growing phases, the plant morphological characteristics and water and light efficiencies were evaluated. Nutrient-uptake efficiencies were also evaluated after the growing phase. It was observed that cuttings rooted under the influence of T1 showed greater height. After the growing phase, plants under T3 showed better results in electricity use efficiency, water use efficiency, and nutrient-uptake efficiency and less nitrate leaching. They also presented more uniform growth with a compact canopy. Thus, T1 was better for the stem cuttings rooting phase, while T3 was better for growth and energy efficiency.

Fungi in ant-plant interactions: a key to enhancing plant nutrient-acquisition strategies.

This article is a Commentary on Gegenbauer et al. (2023), 238: 2210–2223.

Effect and Mechanism of Rice-Pasture Rotation Systems on Yield Increase and Runoff Reduction under Different Fertilizer Treatments

This study investigated the effects of crop rotations and different ratios of dairy manure fertilizer on nitrogen loss and rice yield in the Erhai Lake basin. Two kinds of herbages were set in the rotation: Ryegrass (Lolium multiflorum cv.‘Tetragold’) (R) and Villose Vetch (Vicia villosa var. Glabresens) (V). The experiment involved two-year field tests with nine management treatments. The results showed that the rice-Vicia villosa rotation with 70% chemical and 30% dairy cattle manure fertilization increased rice yield significantly, while reducing nitrogen runoff losses and increasing microbial abundance with nitrification and nitrogen fixation. The microbial abundance varied among tested soils, with Alphaproteobacteria, Rhodopseudomonas, Rhizobiales, Bradyrhizobium, and Azotobacter Vinelandii being the highest in 70% chemical fertilizer + 30% manure rice Villose Vetch (R-V) to ameliorate plant growth and strengthen the efficiency of nutrient uptake, whereas that of Planctomycete was comparatively lower to promote long-term N stabilization in soil. The 70% F—30% M R-V treatment also significantly decreased nitrate reductase and ammonia monooxygenase enzyme activity, potentially improving fertilizer use efficiency, and reducing gaseous losses. The LEfSe analysis results indicated that 70% F—30% M R-V fertilizers significantly enhanced the abundances of metabolic genes related to energy and nitrogen. These findings suggested that appropriate agricultural management using rice-Vicia villosa rotation and 70% chemical + 30% dairy cattle manure fertilization can improve the soil quality and sustainability of agroecosystems.

Reduction in Nitrogen Rate and Improvement of Nitrogen Use Efficiency without Loss of Peanut Yield by Regional Mean Optimal Rate of Chemical Fertilizer Based on a Multi-Site Field Experiment in the North China Plain

It is important to quantify nutrient requirements and optimize fertilization to improve peanut yield and fertilizer use efficiency. In this study, a multi-site field trial was conducted from 2020 to 2021 in the North China Plain to estimate nitrogen (N), phosphorus (P), and potassium (K) uptake and requirements of peanuts, and to evaluate the effects of fertilization recommendations from the regional mean optimal rate (RMOR) on dry matter, pod yield, nutrient uptake, and fertilizer use efficiency. Results show that compared with farmer practice fertilization (FP), optimal fertilization (OPT) based on the RMOR increased peanut dry matter by 6.6% and pod yield by 10.9%. The average uptake rates of N, P, and K were 214.3, 23.3, and 78.4 kg/ha, respectively, with 76.0% N harvest index, 59.8% P harvest index, and 41.4% K harvest index. The OPT treatment increased N, P, and K uptake by 19.3%, 7.3%, and 11.0% compared with FP, respectively. However, the average of yield, nutrition uptake, and harvest indexes of N, P, and K were not significantly affected by fertilization. The peanut required 42.0 kg N, 4.6 kg P, and 15.3 kg K to produce 1000 kg of pods. The OPT treatment significantly improved the N partial factor productivity and N uptake efficiency but decreased the K partial factor productivity and K uptake efficiency. The present study demonstrates that fertilizer recommendations from RMOR improve N use efficiency, and reduce N and P fertilizer application without yield loss in regions with smallholder farmers, and the corresponding estimation of nutrient requirements helps to make peanut fertilization recommendations.

Polar localization of a rice silicon transporter requires isoleucine at both C- and N-termini as well as positively charged residues.

Silicon (Si) is important for stable and high yields in rice (Oryza sativa), a typical Si hyperaccumulator. The high Si accumulation is achieved by the cooperation of 2 Si transporters, LOW SILICON 1 (OsLsi1) and OsLsi2, which are polarly localized in cells of the root exodermis and endodermis. However, the mechanism underlying their polar localization is unknown. Here, we identified amino acid residues critical for the polar localization of OsLsi1. Deletion of both N- and C-terminal regions resulted in the loss of its polar localization. Furthermore, the deletion of the C-terminus inhibited its trafficking from the endoplasmic reticulum to the plasma membrane. Detailed site-directed mutagenesis analysis showed that Ile18 at the N-terminal region and Ile285 at the C-terminal region were essential for the polar localization of OsLsi1. Moreover, a cluster of positively charged residues at the C-terminal region is also required for polar localization. Phosphorylation and Lys modifications of OsLsi1 are unlikely to be involved in its polar localization. Finally, we showed that the polar localization of OsLsi1 is required for the efficient uptake of Si. Our study not only identified critical residues required for the polar localization of OsLsi1, but also provided experimental evidence for the importance of transporter polarity for efficient nutrient uptake.