Plant Dry Biomass Research Articles

Exogenous melatonin reduces water deficit-induced oxidative stress and improves growth performance of Althaea rosea grown on coal mine spoils.

Coal mining activities are responsible for significant land degradation and often long-term irreversible effects on ecosystem functioning. To better understand how coal mined sites could be re-vegetated and ecosystem functioning restored, we address the role of the signalling hormone melatonin, which controls plant growth and development under adverse environmental conditions. We assessed the effects of exogenous melatonin on the plant species Althaea rosea by measuring morphological growth attributes, photosynthetic efficiency, reactive oxygen species (ROS)-induced oxidative damage and antioxidant defence developed by the seedlings when grown on coal-mined spoils under various water regimes. Water deficit and negative effects of coal mine spoils significantly decreased morphological growth attributes (i.e. plant height, root length and dry biomass), gas-exchange traits (i.e. net photosynthesis rate, inter intercellular concentration of CO2, transpiration rate, stomatal conductance and water use efficiency) and photosynthetic pigments (chlorophyll and carotenoid contents) by increasing the ROS-induce oxidative damage and decreasing antioxidant enzyme activities of A. rosea seedlings. However, melatonin applications increased photosynthetic performance and antioxidant enzyme activities and decreased hydrogen peroxide and malondialdehyde contents and ultimately improved growth performance of A. rosea in coal-mined spoils. Overall, our findings show how the application of optimum water (63.0 %field capacity equivalent to 1.67 mm day-1) and melatonin (153.0 μM dose) significantly improves the re-vegetation of coal-mined spoils with A. rosea. Our study provides new insight into melatonin-mediated water stress tolerance in A. rosea grown on coal-mined spoils, and this strategy could be implemented in re-vegetation programmes of coal mine-degraded areas under arid and semiarid conditions of the north-western part of China and perhaps across other arid areas worldwide.

Comparison of Organic and Inorganic Mulching for Weed Suppression in Wheat under Rain-Fed Conditions of Haripur, Pakistan

Weeds pose a great threat to crop production subsequently distressing the equilibrium of agro-ecological systems globally. Instead of relying on chemical weed control, there is a dire need to explore alternative eco-friendly agricultural practices for weed suppression and sustainable wheat production. Mulching being eco-friendly could potentially serve the purpose towards weed suppression organically. To check the usefulness of mulching, two-year studies were conducted under field conditions in Haripur, Pakistan, during 2014 and 2015 to elucidate the response of various mulching materials for weed control in wheat. Six mulch material treatments were used along with Buctril super (used as check) at the rate of 1.235 L ha−1 to control the most problematic weed species of wheat in Pakistan. Experiments were designed under randomized complete block design with four repeats. The analysis of data revealed a significant decrease in weed density, relative weed density, fresh and dry plant biomass at 25, 50 and 75 days after sowing (DAS) where Buctril super at 1.235 L ha−1 and mulch of black plastic were used followed by sugarcane bagasse and dry leaves of mulberry, as compared with control (untreated). Higher density of weed, relative weed density, fresh and dry plant biomass were observed in test weed species of wheat where lentil was applied with wheat and dry leaves of mulberry were incorporated. Net economic benefits in the form of benefit cost ratio (2.55) were higher where grass clippings were applied followed by sugarcane bagasse (2.43), mulberry leaves (2.49), while the lowest net economic benefits (1.72) were obtained when lentil (grown as live mulch crop) with wheat was intercropped. It was concluded from the study that sugarcane bagasse and grass clippings could be a source to control weeds in the wheat with a minimum cost of production at Haripur, Pakistan, and similar agro-climatic environment.

Utilization of indigenous phosphate-solubilizing bacteria to optimize the use of coal fly ash for increasing available-P in an Ultisol

Coal fly ash (CFA) is a coal-burning by-product containing macro and micronutrients, and it is the potential material for improving available P in Ultisols. Phosphate-solubilizing bacteria (PSB) play a role in phosphorus solubilization. This study aimed at elucidating the potential use of phosphate-solubilizing bacteria to optimize the use of coal fly ash for increasing soil available P. This study was conducted in two stages, namely isolation of indigenous PSB from an Ultisol and application of the PSB and CFA to improve soil available P. Five indigenous PSB isolated from the soil had the ability to dissolve phosphate. Isolate B5 could dissolve 9.89 ppm P and had a 99.57% closeness to Pseudomonas stutzeri. The application of 20 and 40 t CFA ha-1 increased the soil pH by 4.2% and 7.2%, respectively. Increasing the dose of CFA decreased the content of available P by 50.6%. However, the combination of PSB and 20 t CFA ha-1 increased soil available P, plant growth, plant dry biomass, and P-uptake by plant.

Effect of lead on growth and physiological responses of Hanjuang plant (Cordyline fruicosa)

The research aimed to analyze the growth and physiological response of Cordyline fruicosa plant. In this study, plants were grown on soil contaminated with lead at various concentrations. The parameters observed included leaf area, the leaves number, stem dry biomass, leaf and roots, photosynthetic pigment, and antioxidant enzyme activity (CAT and APX) which were analyzed after 60 days. The results were plants growth, dry biomass, and photosynthetic pigments decreased with the increasing of lead concentrations while the activity of ascorbate peroxidase (APX) and catalase (CAT) increased. This study signifies the potential of C. fruicosa for lead tolerance.

Pulsed LED Light: Exploring the Balance between Energy Use and Nutraceutical Properties in Indoor-Grown Lettuce

In indoor vertical farms, energy consumption represents a bottleneck for both a system’s affordability and environmental footprint. Although switching frequency (sf) represents a crucial factor in determining the efficacy of light emitting diodes (LED) lighting systems in converting electricity into light, the impact of sf is still underexplored. The aim of this work was to investigate the effect of LEDs sf on the productive and qualitative responses of lettuce (Lactuca sativa L.), also considering the resource use efficiency. Plants were grown for 14 days under red and blue LEDs (215 μmol m−2 s−1 and 16/8 h light/dark, with a red:blue ratio of 3) characterized by two different sf for the blue diode, namely high sf (850 kHz) and low sf (293 kHz). A fluorescent light (same light intensity and photoperiod) was included. LED sf did not alter plant morphological parameters, including fresh or dry biomass, leaf number, leaf area, or water use efficiency. A low sf increased the energy use efficiency (EUE) by 40% as compared to high sf. The latter enhanced the leaf antioxidant capacity, as a consequence of increased concentrations of caftaric and chicoric acids, isoquercetin, and luteolin, consistent with the upregulation of a few genes related to the biosynthetic pathway of phenolic compounds (4C3H and DFR). The study highlights that different sf may significantly affect the EUE as well as crop nutritional properties.

Circular drought-hardening confers drought tolerance via modulation of the antioxidant defense system, osmoregulation, and gene expression in tobacco.

Drought stress hinders the growth and development of crop plants and ultimately its productivity. It is expected that drought stress will be frequent and intense in the future due to drastic changes in the global climate. It is necessary to make crop plants more resilient to drought stress through various techniques; drought-hardening is one of them. Defining various metabolic strategies used by tobacco plants to confer drought tolerance will be important for maintaining plant physiological functions, but studies addressing this topic are limited. This study was designed to elucidate the drought tolerance and adaptation strategies used by tobacco plants via the application of different circular drought-hardening cycles (control: no drought-hardening, T1: one cycle of drought hardening, T2: two cycles of drought-hardening, and T3: three cycles of drought-hardening) to two tobacco varieties namely Honghuadajinyuan (H) and Yun Yan-100 (Y). The results revealed that drought-hardening decreased the fresh and dry biomass of the tobacco plants. The decrease was more pronounced in the T3 treatment for both H (23 and 29%, respectively) and Y (26 and 31%, respectively) under drought stress. The MDA contents, especially in T1 and T2 in both varieties, were statistically similar compared with control under drought stress. Similarly, higher POD, APX, and GR activities were observed, especially in T3, and elevated amounts of AsA and GSH were also observed among the different circular drought-hardening treatments under drought stress. Thus circular drought-hardening mitigated the oxidative damage by increasing the antioxidant enzyme activities and elevated the content of antioxidant substances, a key metabolic strategy under drought stress. Similarly, another important plant metabolic strategy is the osmotic adjustment. Different circular drought-hardening treatments improved the accumulation of proline and soluble sugars contents which contributed to osmoregulation. Finally, at the molecular level, circular drought-hardening improved the transcript levels of antioxidant enzyme-related genes (CAT, APX1, and GR2), proline and polyamines biosynthesis-related genes (P5CS1 and ADC2), and ABA signaling (SnRK2), and transcription factors (AREB1 and WRKY6) in response to drought stress. As a result, circular drought-hardening (T2 and T3 treatments) promoted tolerance to water stress via affecting the anti-oxidative capacity, osmotic adjustment, and regulation of gene expression in tobacco.

Molybdenum-Induced Regulation of Antioxidant Defense-Mitigated Cadmium Stress in Aromatic Rice and Improved Crop Growth, Yield, and Quality Traits.

Cadmium (Cd) stress causes serious disruptions in plant metabolism, physio-biochemical responses, crop yield, and grain quality characteristics. A pot experiment was conducted to investigate the role of molybdenum (Mo) in mitigating Cd-induced adversities on plant growth, yield attributes, and grain quality characteristics of a popular aromatic rice cultivar ‘Xiangyaxiangzhan’. The Mo was applied at 0.15 mg kg−1 soil in both control (no Cd) and Cd-contaminated (100 mg kg−1) soils. A treatment with Mo-free (−Mo) soil was also maintained for comparison. The results showed that Cd toxicity significantly (p < 0.05) reduced plant dry biomass, grain yield, photosynthetic efficiency, and pigment contents, and impaired chloroplast ultra-structural configuration and simultaneously destabilized the plant metabolism owing to higher accumulation of hydrogen peroxide, electrolyte leakage, and malondialdehyde contents. However, Mo supply improved grain yield and 2-acetyl-1-pyrroline content by 64.75% and 77.09%, respectively, under Cd stress, suggesting that Mo supply mitigated Cd-provoked negative effects on yield attributes and grain quality of aromatic rice. Moreover, Mo supply enhanced photosynthesis, proline, and soluble protein content, and also strengthened plant metabolism and antioxidant defense through maintaining higher activities and transcript abundance of ROS-detoxifying enzymes at the vegetative, reproductive, and maturity stages of aromatic rice plants under Cd toxicity. Collectively, our findings indicated that Mo supply strengthened plant metabolism at prominent growth stages through an improved enzymatic and non-enzymatic antioxidant defense system, thereby increasing grain yield and quality characteristics of aromatic rice under Cd toxicity.

Growth and Yield Response of Groundnut (Arachis hypogea L.) to Inorganic Fertilisers at Luyengo, Middleveld of Eswatini

Groundnut is an important food and cash crop for smallholder farmers in Eswatini. However, its yield is very low partly due to poor soil fertility particularly calcium and phosphorus deficiencies associated with soil acidity. Thus, a field experiment was conducted to determine the effects of different inorganic fertiliser types on growth and yield of groundnut. The treatments were: a control with no fertiliser, [2:3:2 (22) at 300 kg ha-1], single superphosphate (100 kg ha-1), calcium nitrate (120 kg ha-1) and a combination of calcium nitrate (120 kg ha-1) and single superphosphate (100 kg ha-1). A randomised complete block design (RCBD) with three replications was used. Results showed highly significant (p&lt;0.01) differences among the fertiliser types on most of the growth parameters recorded. At 90% flowering, significantly highest number of leaves per plant (48.3), the tallest plant (42.17 cm), the highest canopy width (41.47 cm), the highest number of branches per plant (6.57) and plant dry biomass per plant (20.6 g) were recorded for treatments with calcium nitrate followed by the application of combination of calcium nitrate and single superphosphate. Similarly, most of the yield components and yield were significantly (p&lt;0.05) affected by the fertiliser types. Significantly highest numbers of total pods per plant (28.8), mature pods per plant (26.9), dry pod yield (950.6 kg ha-1), hundred seed mass (82.8 g), shelling percentage (70.6) and seed yield (671.6 kg ha-1) were recorded from a combination of calcium nitrate and single superphosphate fertiliser. Thus, combined application of 120 kg ha-1 calcium nitrate and 100 kg ha-1 single superphosphate fertilisers can be used to increase the productivity of groundnut in the study area.

Behavior of Cucumis sativus L. in presence of aluminum stress: Germination, plant growth, and antioxidant enzymes.

Aluminum (Al) is an ubiquitously present element in soil; it is considered as a major problem in crop production that affects plant growth and development on acid soils. The aim of this work was to determine the germination parameters, to quantify the water status and growth, to assess the Al accumulation, and antioxidant enzyme activities in plants to evaluate the stress exerted by aluminum in Cucumis sativus L. For germination test, increasing doses of Al were used (0, 200, 500, 1,000, and 2,000 μM). Results showed that germination was stimulated with 500 of Al. Aluminum effects on development were studied by treating the plants with different concentrations of Al (100, 200, 300, and 500 µM, Al) during 45 days. As regards to the plant's growth, water content, and dry biomass production there was a slight increase. On the other hand, the activities of the antioxidant enzymes were disturbed by aluminum stress. Data indicate that the catalase (CAT) activity showed a decrease in the different parts of the plant. However, guaiacol peroxidase (GPX) and ascorbate peroxidase (APX) activities were significantly stimulated. Studying the effects of Al‐induced stress allowed us to conclude that cucumber has a high ability to accumulate this element in the roots.

Zinc Oxide Nanoparticles Alleviate Chilling Stress in Rice (Oryza Sativa L.) by Regulating Antioxidative System and Chilling Response Transcription Factors.

As one of the common abiotic stresses, chilling stress has negative effects on rice growth and development. Minimization of these adverse effects through various ways is vital for the productivity of rice. Nanoparticles (NPs) serve as one of the effective alleviation methods against abiotic stresses. In our research, zinc oxide (ZnO) NPs were utilized as foliar sprays on rice leaves to explore the mechanism underlying the effect of NPs against the negative impact of chilling stress on rice seedlings. We revealed that foliar application of ZnO NPs significantly alleviated chilling stress in hydroponically grown rice seedlings, including improved plant height, root length, and dry biomass. Besides, ZnO NPs also restored chlorophyll accumulation and significantly ameliorated chilling-induced oxidative stress with reduced levels of H2O2, MDA, proline, and increased activities of major antioxidative enzymes, superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). We further found that foliar application of ZnO NPs induced the chilling-induced gene expression of the antioxidative system (OsCu/ZnSOD1, OsCu/ZnSOD2, OsCu/ZnSOD3, OsPRX11, OsPRX65, OsPRX89, OsCATA, and OsCATB) and chilling response transcription factors (OsbZIP52, OsMYB4, OsMYB30, OsNAC5, OsWRKY76, and OsWRKY94) in leaves of chilling-treated seedlings. Taken together, our results suggest that foliar application of ZnO NPs could alleviate chilling stress in rice via the mediation of the antioxidative system and chilling response transcription factors.

Arbuscular mycorrhizal inoculation increases drought tolerance and survival of Cenostigma microphyllum seedlings in a seasonally dry tropical forest

Seasonally dry tropical forests are characterized by several months of drought. Cenostigma microphyllum is a native woody species widely found in a seasonally dry tropical forest. These forests are in need of restoration and C. microphyllum is a species that can be used to this end. We studied, 1) acute water deficiency using plant in pot, and 2) chronic water deficiency in field conditions in areas with different rainfall gradients, always with two group of plants: inoculated and non-inoculated with arbuscular mycorrhizal fungus. Acute water deficit levels in previously inoculated and non-inoculated treatments were similar, however, after rehydration, the inoculated potted plants showed faster recovery of water status and gas exchange. In field conditions, on the 120th day, before the beginning of the dry period, 100% of transplanted seedlings survived, while the total plant dry biomass did not differ between the inoculated and control groups. The same patterns emerged across rainfall gradient. After 365 days of seedling transplantation, the field survival dropped from 100% to 58%. Sixty-eight percent of the inoculated plants survived, whereas more than half of the non-inoculated individuals did not resprout at the beginning of the rainy season. Among the remaining plants, 63% were from the rainiest plots. The average of CO2 assimilation for both treatments was 2.63 and 9.43 μmol m−2 s−1 in the two driest and wettest plots, respectively. Our results suggest that artificial inoculation appears to be associated with better plant recovery or resilience following low water availability, particularly chronic/prolonged drought. Thus, the present work recommends the use of the seedling production technique, with long roots as well as the previous inoculation with selected native mycorrhizal fungi.

The potential of microbes and sulfate in reducing arsenic phytoaccumulation by maize (Zea mays L.) plants.

Arsenic (As) contamination in soil-plant system is an important environmental, agricultural and health issue globally. The microbe- and sulfate-mediated As cycling in soil-plant system may depend on soil sulfate levels, and it can be used as a potential strategy to reduce plant As uptake and improve plant growth. Here, we investigated the role of soil microbes (SMs) to examine As phytoaccumulation using maize as a test plant, under varying sulfate levels (S-0, S-5, S-25mmolkg-1) and As stress. The addition of sulfate and SMs promoted maize plant growth and reduced As concentration in shoots compared to sulfate-treated plants without SMs. Results revealed that theSMs-S-5 treatment proved to be the most promising in reducing As uptake by 27% and 48% in root and shoot of the maize plants, respectively. The SMs-S treatments, primarily with S-5, enhanced plant growth, shoot dry biomass, Chl a, b and total Chl (a + b) contents, and gas exchange attributes of maize plants. Similarly, the antioxidant defense in maize plants was increased significantly in SMs-S-treated plants, notably with SMs-S-5 treatment. Overall, the SMs-S-5-treated plants possessed improved plant growth, dry biomass, physiology and antioxidant defense system and decrease in plant shoot As concentration. The outcomes of this study suggest that sulfate supplementation in soil along with SMs could assist in reducing As accumulation by maize plants, thus providing a sustainable and eco-friendly bioremediation strategy in limiting As exposure.

Piedra pómez, tezontle y soluciones nutritivas en el cultivo de tomate cherry

El uso de sustratos minerales locales de bajo costo y soluciones nutritivas con la composición química adecuada pueden ser la alternativa para maximizar el potencial de producción de tomate cherry (Solanum lycopersicum L.). El objetivo del presente estudio fue evaluar sustratos de la zona de Nayarit en combinación con soluciones nutritivas, sobre el crecimiento, contenido nutrimental y producción de tomate cherry. La investigación se realizó en Nayarit, México. El diseño experimental fue completamente al azar con arreglo bifactorial, los factores fueron los sustratos piedra pómez y tezontle, y las soluciones nutritivas de Steiner y Castellanos, esto originó cuatro tratamientos con 11 repeticiones, donde una repetición fue una planta a dos tallos. Se determinaron las variables altura de planta, diámetro de tallo, área foliar, biomasa seca de parte aérea, biomasa seca de raíz, producción de fruto por planta, unidades SPAD y contenido nutrimental foliar (N, P y K). Los resultados mostraron que la solución nutritiva de Steiner incrementó la producción de fruto y también el crecimiento evaluado en altura de planta, diámetro de tallo y biomasa seca de raíz. El contenido nutrimental de N, P y K fue superior con la solución de Castellanos. En el sustrato piedra pómez la producción de fruto, crecimiento de planta y contenido nutrimental fueron más altos en relación a las plantas en tezontle. Se concluyó que el sustrato piedra pómez en combinación con la solución nutritiva de Steiner fue la más viable para tomate cherry, ya que favoreció el crecimiento de planta y producción de fruto.

Phosphate-lanthanum coated sewage sludge biochar improved the soil properties and growth of ryegrass in an alkaline soil

The reclamation of alkaline soils remains challenging while the application of biochar has been proposed as a viable measure to rehabilitate soil fertility. The objective of the current pot study was to evaluate the efficacy of various P-La modified sewage sludge biochars (SSBC, La-SSBC, SSBC-P, La-SSBC-P) on soil phosphate-retention and ryegrass (Lolium perenne L.) growth in an alkaline soil (excess CaCO3). The results revealed that germination percentage, plant dry biomass, plant height, and the total amount of P in the ryegrass leaves were significantly (P < 0.05) improved under La-SSBC-P treatment as compared to other treatments. La-SSBC-P treatment significantly altered the chemical characteristics of post-harvest alkaline soil, such as pH, electrical conductivity (EC), cation exchange capacity (CEC), soil organic matter (SOM), limestone (CaCO3), phosphate, and lanthanum contents. In comparison to the SSBC treatment, soil available phosphorous (AP) contents under La-SSBC-P were enhanced by 6.7 times after loading biochar with P and La (La-SSBC-P). After the plantation of ryegrass, concentration of lanthanum in the soil was negligible. The contents of CaCO3 reduced by 76.2% after La-SSBC-P biochar treatment, compared to the cultivated control. This phenomenon clearly indicated that lanthanum was reduced due to the precipitation with limestone, which was proposed based on the data of X-ray diffraction (XRD) analysis. Overall, results showed that the P-loaded lanthanum decorated biochar (La-SSBC-P) could be used as a potential substitute for P-fertilizer under the experimental conditions. However, field experiments are required to confer the efficiency of La-SSBC-P as P fertilizer in different soils.

Effects of Combined Biochar and Vermicompost Solution on Leachate Characterization and Nitrogen Balance from a Greenhouse Tomato (Solanum Lycopersicum) Cultivation Soil

ABSTRACT Both biochar (B) and vermicompost (V) can provide the soil with soluble organic matter. We evaluated the effect of B in reducing nitrate and dissolved organic carbon (DOC) losses from soil via leaching together with the effect of B combined with V solution (vermiwash) in increasing the efficiency of plant nitrogen. Tomato plants (Solanum lycopersicum L.) were cultivated in a greenhouse with soil under three different amendments (B, V and a mix BV). B was applied at a rate of 2% w/w corresponding to 34 t ha−1. V was applied at 25 mg per plant through fertigation. Leachate and soil were monitored in terms of nitrates and DOC throughout the trial (120 days), and plants and fruits were monitored in terms of nitrogen balance index (NBI) and dry matter biomass. B and BV significantly decreased NO3 –_N content in the leachate in all recovered times by 66.8% and 71.3%, respectively. In contrast, the absence of biochar in the V treatment led to a 38.1% increase in NO3 –_N concentration. Similar results were found for DOC content. The dry biomass of plants increased in B and BV treatments by 19.5 and 28.7%, respectively. The dry biomass of tomato fruits was enhanced by 18.5, 12.1, and 37% in V, B and BV treatments, respectively. Synergisms were found between the char material and complex organic compounds derived from the vermicompost process in terms of safeguarding the quality of the soil, the underground water, and the sustainability of crops.

Physiological and biochemical responses of Agave to temperature and climate of their native environment

The assessment of phenotypic variation across populations can help to select genotypes that are potentially resistant to the ongoing and predicted climatic variations. Phenotypic variation is expressed as morphological, physiological, or metabolic changes in response to environmental factors. Agave mapisaga and A. salmiana populations exhibit morphological variation regarding their geographical distribution and due to intense anthropogenic influence. This study aimed to identify metabolic traits in young plants of A. mapisaga and A. salmiana, involved in plant resistance to temperature stress, which can help to understand differences between provenances and between species. Agave plants propagated from four seed origins, collected from three “pulque” (a fermented beverage) production areas in the state of Hidalgo, Mexico, were assessed. Four-month-old plants of each seed origin (species*provenance) were maintained during one month in growth chambers, at day/night temperature (T) regimes for 12/12 h: (1) 25/25T, (2) 25/15T, and (3) 25/15 plus 45 °C T for 4 h between 11 am and 3 pm (45T). The plant dry biomass, maximum quantum efficiency of PSII photochemistry (Fv/Fm), total free amino acids (TFAA), total free phenol (TFP), and free soluble sugar concentrations were measured. Minimum values for dry biomass, TFP, glucose, and sucrose concentrations occurred in the 25/25T regime. Plant biomass, and TFAA and glucose concentrations were differently affected by seed provenances; but Fv/Fm rate, or the TFP, fructose, and sucrose concentrations had no relation to seed provenance. Moderate high night temperatures drastically affected the growth and metabolism of A. mapisaga and A. salmiana. In conclusion, the response to different temperature stress treatments depends partly on species, but less on seed provenance.

The effect of biological fertilizer application on soil fertility, heavy metals reduction and eggplant yield on the rice field of Bantul regency

Biofertilizer contains microorganisms which promote the adequate supply of nutrients to the host plants and ensure their proper development of growth and regulation in their physiology. They are in being promoted to harvest the naturally available nutrients and biological system of nutrients mobilization. This research aims to determine the effect of Silitech biofertilizers on soil fertility, heavy metal reduction and eggplant yields. The study was conducted in Piyungan District–Bantul on dry season of 2019. Research design was used a Randomized Complete Block Design with 7 treatments and 4 replications. Each treatment was applied in a plot size 8 m x 1.2 m and given a plastic mulch. The kind of treatments are: P0 (Control), P1 (100% NPK based on fertilizer recommendation), P2 (100% Biofertilizer), P3 (Biofertilizer + 25% NPK), P4 (Biofertilizer + 50% NPK), P5 (Biofertilizer + 75% NPK), P6 (Biofertilizer + 100% NPK). The result of study showed that application of Biofertilizer +75%NPK had a significant effect on increasing eggplant yield., dry plant biomass and the levels of C, N, P and K about 26,92 - 32,76% compare to the control treatment as well as increasing some micro elements, such as Ca, Mg, B, Zn and Mo compared to the treatment that given only 100% biological fertilizer and Biological fertilizer + 25% NPK but it was not significantly different from the application of Biological fertilizer + 100% NPK. Moreover, The Silitech biofertilizer also can reduce the levels of heavy metals content of Hg, Pb and Cd as much as 30.76-46.15%, 29.45-39.81% and 35.1-47.5% respectively. which indicated by the decreased their content after harvesting eggplant.

Small structures with big impact: Multi-walled carbon nanotubes enhanced remediation efficiency in hyperaccumulator Solanum nigrum L. under cadmium and arsenic stress

With the fast development of nanotechnology, nanomaterials are being increasingly applied for the remediation of contaminated soils. However, few researches have been reported on the complex interactions of carbon nanotubes with heavy metal (loid)s in phytoremediation. Here, we conduct a pot experiment to investigate the effects of multi-walled carbon nanotubes (MWCNTs) on the plant growth and behavior of heavy metal (loid)s in hyperaccumulator-soil system. Cd hyperaccumulator Solanum nigrum L. (S. nigrum) were cultivated in Cadmium (Cd) and Arsenic (As) contaminated soils amended with MWCNTs at 100, 500, and 1000 mg kg−1 for 60 days, respectively. The application of MWCNTs increased the shoot length and plant dry biomass by 5.56%∼25.13% and 5.23%∼27.97%. Whereas, root and leaf growth were inhibited in 1000 mg kg−1 MWCNTs treatments. Meanwhile, MWCNTs at 500 mg kg−1 significantly enhanced the accumulation of heavy metal (loid)s in S. nigrum（18.29% for Cd and 32.47% for As）and alleviated co-contamination induced toxicity, by motivating plant growth, stimulating antioxidant enzymatic activities, and increasing micronutrient content (p < 0.05). The bio-concentration factor of As was decreased (15.31–28.08%) under MWCNTs application, which plays an important role in the alleviation of phytotoxicity. Besides, bioavailable Cd and As were reduced in rhizosphere soils, and the most significant reduction (16.29% for Cd and 8.19% for As) were shown in 500 mg kg−1 MWCNTs treatment. These findings demonstrate that suitable concentration of MWCNTs can enhance remediation efficiency. Our study gives a strong evidence to promote the phytoremediation for co-contaminated soils by using nanomaterials.

Inoculation of Triticum Aestivum L. (Poaceae) with Plant-Growth-Promoting Fungi Alleviates Plant Oxidative Stress and Enhances Phenanthrene Dissipation in Soil

Polycyclic aromatic hydrocarbons (PAHs) are strong toxic compounds mainly released to the environment during combustion of fossil fuels, and have strong toxic effects on living organisms, with soil being one of their main reservoirs. High PAH levels in soils can interfere with plant growth and biomass production, causing several losses of diversity. In this study, we evaluated the effects of the co-inoculation of Trichoderma viride and Funneliformis mosseae on PAH dissipation and alleviation of oxidative stress in Triticum aestivum L. (wheat) plants growing in a phenanthrene-spiked soil. We determined the effect of single and dual fungal inoculation on phenanthrene dissipation rates, soil enzyme activities, dry biomass, antioxidant enzymes, lipid peroxidation, and organic acid exudation of plants growing in a soil spiked with phenanthrene at 500 and 1000 mg kg−1 soil. The co-inoculation with T. viride and F. mosseae resulted in a high phenanthrene dissipation from the soil. Also, dry biomass, soil enzymes, antioxidant response, organic acid exudation and phenanthrene content in roots were increased by the dual inoculation treatments, whereas lipid peroxidation and phenanthrene content in shoots were reduced. Our results show that the co-inoculation with these two soil fungi significantly promotes phenanthrene dissipation from soil and contributes to alleviating oxidative damage in wheat plants exposed to high levels of phenanthrene.

Nutrient Availability to Maize Crop (Zea mays L.) in Biochar Amended Alkaline Subtropical Soil

Biochar application variably affects nutrients availability, growth, and yield of crop plants based on their feedstock type and pyrolysis conditions. A pot experiment was carried out to evaluate the effect of biochars prepared from three different feed stocks viz. sugarcane filter cake (SF-BC), farmyard manure (FM-BC), and rice husk (RH-BC), on the availability of the plant nutrients in soil and the growth and nutrient uptake by maize crop (Zea mays L.). The biochars were applied separately to the soil at the rate of 0, 0.25, 0.5, and 1% separately, and the experiment was laid out according to two-factor factorial completely randomized design (CRD) maintaining three replications. Maize variety Monsanto-DK8031 was sown as the test crop. The concentration of total nitrogen (N), nitrate (NO3-N), ammonium (NH4-N), microbial biomass nitrogen (MBN), Olsen phosphorus (P), and extractable K increased with the addition of FM-BC, while the SF-BC increased soil microbial biomass phosphorus (MBP) and micronutrients (Zn, Mn, Cu, Fe) availability in the soil. Moreover, the biochar application significantly improved crop growth parameters (i.e., plant height, fresh plant weight and dry biomass) and also increased plant nutrient concentration and uptake. No negative impact of biochar was observed on plant growth or nutrients concentration. The macronutrient (total N, P, and K) contents and their uptakes were higher in plants grown with RH-BC, while the micronutrient (Mn, Cu, and Fe) contents were higher in plants grown with SF-BC. Biochar as an organic amendment has a great potential to improve soil fertility status and nutrients availability to crop plants in tropical alkaline soils; however, the effectiveness varies with the feed stock type and application rate.