Plant Tissue Analysis Research Articles

Biotic phase micropollutant distribution in horizontal sub-surface flow constructed wetlands

The distribution of micropollutants in biotic phases of horizontal sub-surface flow (HSSF) constructed wetlands was investigated. 88 diverse micropollutants (personal care products, pharmaceuticals and illicit drugs) were monitored for in full-scale HSSF steel slag and gravel beds to assess their fate and behaviour during tertiary wastewater treatment. Of the studied micropollutants 54 were found in receiving and treated wastewaters. Treatment reduced concentrations of several micropollutants by >50% (removal range −112% to 98%) and resulted in changes to the stereo-isomeric composition of chiral species. For example, stereo-selective changes were observed for 3,4-methylenedioxymethamphetamine (MDMA) and atenolol during HSSF constructed wetland treatment for the first time. Analysis of sludge present within the HSSF beds found 37 micropollutants to be present. However, concentrations for the majority of these micropollutants were not considered high enough to suggest partitioning into sludge was a contributing mechanism of removal. Nevertheless the preservative methylparaben was found at 2772mgbed−1. Its daily removal from wastewater of 3.4mgd−1 indicates partitioning and accumulation in sludge contributes to its removal. Other micropollutants found at high levels in sludge (relative to their overall removals) were the antidepressants sertraline and fluoxetine, and the metabolite desmethylcitalopram. Furthermore, process balances indicated uptake and metabolism by Phragmites australis (Cav.) Trin. ex Steud did not contribute significantly to micropollutant removal. However analysis of plant tissues evidenced uptake, metabolism and accumulation of recalcitrant micropollutants such as ketamine and carbamazepine. It is considered that the rate of uptake was too slow to have a notable impact on removal at the 14h hydraulic retention time. Despite evidence of other removal mechanisms at play (e.g., partitioning into sludge and plant uptake), findings indicate biodegradation is the dominant mechanism of micropollutant removal in HSSF constructed wetlands.

Macro and Micronutrient Storage in Plants and Their Remobilization When Facing Scarcity: The Case of Drought

Human mineral malnutrition or hidden hunger is considered a global challenge, affecting a large proportion of the world’s population. The reduction in the mineral content of edible plant products is frequently found in cultivars bred for higher yields, and is probably increased by intensive agricultural practices. The filling of grain with macro and micronutrients is partly the result of a direct allocation from root uptake and remobilization from vegetative tissues. The aim of this bibliographic review is to focus on recent knowledge obtained from ionomic analysis of plant tissues in order to build a global appraisal of the potential remobilization of all macro and micronutrients, and especially those from leaves. Nitrogen is always remobilized from leaves of all plant species, although with different efficiencies, while nutrients such as K, S, P, Mg, Cu, Mo, Fe and Zn can be mobilized to a certain extent when plants are facing deficiencies. On the opposite, there is few evidence for leaf mobilization of Ca, Mn, Ni and B. Mechanisms related to the remobilization process (remobilization of mineral forms from vacuolar and organic compounds associated with senescence, respectively) are also discussed in the context of drought, an abiotic stress that is thought to increase and known to modulate the ionic composition of grain in crops.

Proteomic Analysis of Non-model Plant Tissues Using Phenol Extraction, Two-Dimensional Electrophoresis, and MALDI Mass Spectrometry.

Separation of plant proteins by means of electrophoretic techniques is quite challenging since different compounds typical for plant cells can interfere and/or reduce the effectiveness of the protein isolation. This is particularly problematic for two-dimensional electrophoresis (2-DE). Therefore, it is important to optimize protein extraction and to establish a robust protocol for 2-DE and downstream processing, primarily mass spectrometry (MS) analysis. Here we give a detailed protocol for protein extraction using phenol method, 2-DE, and MALDI-MS analysis.

Effect of different concentrations of vermicompost-tea and Dupinix organic fertilizer on some characteristics of spinach (Spinacia oleraceae L.)

Spinach (Spinacia oleraceae L.) is an important leafy vegetable and belongs to Chenopodiaceae family. This research was carried out in order to evaluate the effect of different concentrations of vermicompost-tea and Dupinix® organic fertilizer on some characteristics of spinach cv. “Oriental Pride”. The experiment was done in randomized complete block design with three replications. Treatments were five vermicompost-tea concentrations (0, 20, 40, 60 and 80%) and organic fertilizer Dupinix® in four concentrations (1, 2, 3 and 4 per 1000 V/v). Results indicated that the foliar application of both the fertilizers had significant effects on evaluated characteristics. The highest (28.96 g) and lowest (14.47 g) plant fresh weight were measured in Dupinix® 4 per 1000 V/v and control treatments, respectively. Plants were treated with both of fertilizes had higher amount of leaf area than control. The highest total phenolic content (58 mg/kg) was measured from Dupinix® 3 and 4 per 1000 V/v and the lowest (43 mg/kg) in the control treatment. Elements analysis of plant tissue showed that treated plants with organic fertilizer had higher concentration compared to control. It was suggested that vermicompost-tea and Dupinix® fertilizer could be used to improve important parameters of spinach.

Easy sectioning of whole grain of rice using cryomicrotome.

To obtain a clear intact section of a ripened rice grain, which is suitable for biochemical and histological analysis, the Kawamoto method using a specific adhesive film was applied using a cryomicrotome. The longitudinal and sagittal sections were easily obtained together with the cross-section, and cell characteristics were clearly discerned in the ripened grain. It was demonstrated that the Kawamoto method is readily applicable for intact sectioning of hard tissue, including ripened grain. Intact section sampling may be useful for enzymatic analysis and transcriptomic analysis of plant tissue.

Evaluation of nutrient uptake of selected cover crops and biochar on the yield advantage of two taro (Colocasia esculenta) cultivars in Samoa

A study was conducted in three agro ecological zones of Samoa to compare the dry matter yields and nutrient uptake of selected tropical cover crops and biochar application on different Samoan inceptisols. Subsequent improvements in corm yield of the two taro cultivars, (Samoa 1 and Samoa 2), under these fallow systems were also determined. The split-plot arrangement with main plots as cover crops and subplots as the cultivars was used, with four replications. The evaluated cover crops included: a reference – grass fallow treatment (farmers practice), Mucuna pruriens, Erythrina subumbrans, Mucuna pruriens + 200 kg of NPK fertiliser (12-5-20), farmer’s reference practice + 400 kg of NPK fertiliser (12-5-20), and biochar produced from coconut shells. The biomass samples were collected after the six month of fallow duration. Plant tissue analyses revealed that the nitrogen and the phosphorus contents of erythrina was higher than corresponding mucuna cover across all three sites. However, as a result of higher biomass production, Mucuna pruriens showed the highest nutrient accrual over the six month fallow duration. The general yield trend under different fallow practices across all the sites indicates that mucuna with modest supplementation of complete fertilisers can help maintain optimum taro yields. However, it appears that the yield responses of the taro crop to fallow treatments are site-specific.

Plant Tissue Analysis to Assess Phosphorus and Potassium Nutritional Status of Corn and Soybean

Core Ideas There is a need for developing more reliable interpretations for tissue tests in corn and soybean. Tissue testing has no widespread use in many regions partly due to lack of reliable interpretations. We determined critical P and K concentrations at vegetative and reproductive growth stages. There is a need for reevaluating the value of tissue testing in corn (Zea mays L.) and soybean [Glycine max (L.) Merr.] for current yield levels and genotypes. The objective of this research was to determine tissue critical P and K concentrations for these crops at vegetative and reproductive growth stages. Response trials were conducted in Iowa at 30 sites for P (32 site‐years with corn and 34 with soybean) and at 53 sites for K (67 site‐years with corn and 52 with soybean). We sampled whole plants at the V5‐V6 stage, corn ear‐leaf blades at the R1 stage, and trifoliate soybean leaves at the R2‐R3 stage. Critical concentration ranges (CCRs) were defined using linear‐plateau and quadratic‐plateau models. All models fit significantly (P ≤ 0.01). Model R2 values were the lowest (0.31–0.45) for corn plant P, soybean plant and leaf P, and soybean plant K; intermediate (0.51–0.53) for corn plant and leaf K and soybean leaf K; and the highest (0.62–0.64) for corn leaf P. For corn plants and leaves, CCRs were 4.8 to 5.5 and 2.5 to 3.1 g P kg¯1 and 18.8 to 25.4 and 10.6 to 14.2 g K kg¯1, respectively. For soybean plants and leaves, CCRs were 3.3 to 4.1 and 3.5 to 4.7 g P kg¯1 and 18.9 to 22.7 and 15.6 to 19.9 g K kg¯1, respectively. Testing of corn ear‐leaves for P was more accurate than for plants but either tissue provided similar K assessments. Testing soybean plants for P was more accurate than for leaves, but for K testing of leaves was more accurate than for plants.

The effect of foliar application of Moringa leaf extract on biomass, grain yield of wheat and applied nutrient efficiency

ABSTRACTMoringa leaf extracts (MLE) from two varieties of Moringa oleifera Lam. were applied to leaves of wheat (Triticum aestivum L.) in two glasshouse experiments. MLE was extracted from the leaves of using three different solvents (hexane, butanol; ethyl-acetate). The extracts were applied as foliar sprays at different growth stages of wheat (T. aestivum L.) grown on two soil types with either adequate or low phosphorus (P) nutrient additions at Albany, Western Australia. Sprays were applied at the 4–5 leaf (tillering) and the 7-leaf (Boot) stage either as a single spray or a combination of sprays at tillering and boot stage. The application of MLE either at tillering or boot stage increased the dry weight of shoots (biomass) and grain yield of wheat. A foliar spray of MLE applied at tillering increased biomass at the boot stage by ∼37% and grain yield increased by ∼34% compared to nil MLE spray. A single spray of MLE increased grain yield by ∼30% when applied at boot stage. A single application at tillering gave a better yield response than a single spray at the 7-leaf or boot or than a double spray applied at tillering and boot stage. A 50% dilution of the extractant concentration gave the same grain yield response as the original concentration applied at tillering stage. The hexane extracts gave the significantly higher grain yield responses. Plant tissue and grain analysis showed no significant difference in protein and nutrient concentration of wheat grain from plants sprayed with and without MLE. A MLE spray at boot also increased grain yield by 44% on the red sandy-loam soil where P application was at sub-optimum levels, ∼80% of P requirement for maximum yield. The partial factor productivity (PFP) index indicated that the P and potassium (K) use improved where MLE was applied as a foliar spray. For example, the PFP of P and K for grain yield increased by about 30%, where MLE was sprayed to foliage. The results of this study indicate that MLE extracted can potentially be a viable option to increase wheat grain yield and fertilizer efficiency use, particularly P and K, in Mediterranean wheat production system.

English

The objective of this work was to evaluate the effect of different forms of reimplantation of pasture with and without phosphatation aiming to contribute to the increase of soybean yield. The experiment was conducted at the Experimental Farm of Universidade do Oeste Paulista (Unoeste), located in the municipality of Presidente Bernardes - SP. The design was done with split plot scheme, containing four replicates. The plots were constituted with 4 kg ha-1 of Urochloa brizantha (Marandu grass), BNS + Seeding in haul, BNS + Seeding in line consortium with soybean as subplots (with and without phosphatation). The following were analyzed: number of tillers and dry mass yield (PMS); analysis of plant tissue from pasture; foliar diagnosis analysis; and components of production and production of soy. Analyzed variables were submitted to analysis of variance (p <0.05) and means were compared by the Tukey test (p <0.05). In this context, it can be concluded that a higher quality production with a reimplantation of pasture intercropped with a soybean crop yielding an increase of 276 kg ha-1 compared to the treatment that did not have pasture reimplantation (BNS). Phosphate increased soil phosphorus content in the production of soybean dry matter and no leaf phosphorus content and higher soybean yield. Key words: Natural seed bank, no-tillage, Urochloa brizantha.

Determination of diagnostic standards on saturated soil extracts for cut roses grown in greenhouses.

This work comprises the theoretical determination and validation of diagnostic standards for the analysis of saturated soil extracts for cut rose flower crops (Rosa spp.) growing in the Bogota Plateau, Colombia. The data included 684 plant tissue analyses and 684 corresponding analyses of saturated soil extracts, all collected between January 2009 and June 2013. The tissue and soil samples were selected from 13 rose farms, and from cultivars grafted on the 'Natal Briar' rootstock. These concurrent samples of soil and plant tissues represented 251 production units (locations) of approximately 10,000 m2 distributed across the study area. The standards were conceived as a tool to improve the nutritional balance in the leaf tissue of rose plants and thereby define the norms for expressing optimum productive potential relative to nutritional conditions in the soil. To this end, previously determined diagnostic standard for rose leaf tissues were employed to obtain rates of foliar nutritional balance at each analyzed location and as criteria for determining the diagnostic norms for saturated soil extracts. Implementing this methodology to foliar analysis, showed a higher significant correlation for diagnostic indices. A similar behavior was observed in saturated soil extracts analysis, becoming a powerful tool for integrated nutritional diagnosis. Leaf analyses determine the most limiting nutrients for high yield and analyses of saturated soil extracts facilitate the possibility of correcting the fertigation formulations applied to soils or substrates. Recommendations are proposed to improve the balance in soil-plant system with which the possibility of yield increase becomes more probable. The main recommendations to increase and improve rose crop flower yields would be: continuously check pH values of SSE, reduce the amounts of P, Fe, Zn and Cu in fertigation solutions and carefully analyze the situation of Mn in the soil-plant system.

Laser-ablation electrospray ionization mass spectrometry with ion mobility separation reveals metabolites in the symbiotic interactions of soybean roots and rhizobia.

Technologies enabling insitu metabolic profiling of living plant systems are invaluable for understanding physiological processes and could be used for rapid phenotypic screening (e.g., to produce plants with superior biological nitrogen-fixing ability). The symbiotic interaction between legumes and nitrogen-fixing soil bacteria results in a specialized plant organ (i.e., root nodule) where the exchange of nutrients between host and endosymbiont occurs. Laser-ablation electrospray ionization mass spectrometry (LAESI-MS) is a method that can be performed under ambient conditions requiring minimal sample preparation. Here, we employed LAESI-MS to explore the well characterized symbiosis between soybean (Glycine max L. Merr.) and its compatible symbiont, Bradyrhizobium japonicum. The utilization of ion mobility separation (IMS) improved the molecular coverage, selectivity, and identification of the detected biomolecules. Specifically, incorporation of IMS resulted in an increase of 153 differentially abundant spectral features in the nodule samples. The data presented demonstrate the advantages of using LAESI-IMS-MS for the rapid analysis of intact root nodules, uninfected root segments, and free-living rhizobia. Untargeted pathway analysis revealed several metabolic processes within the nodule (e.g., zeatin, riboflavin, and purine synthesis). Compounds specific to the uninfected root and bacteria were also detected. Lastly, we performed depth profiling of intact nodules to reveal the location of metabolites to the cortex and inside the infected region, and lateral profiling of sectioned nodules confirmed these molecular distributions. Our results established the feasibility of LAESI-IMS-MS for the analysis and spatial mapping of plant tissues, with its specific demonstration to improve our understanding of the soybean-rhizobial symbiosis.

Landscape, Soil, and Plant Analysis of Japanese Stiltgrass (Microstegium vimineum) Invasion in the Piedmont Region, SC

ABSTRACTJapanese stiltgrass (Microstegium vimineum), an exotic invasive plant, is native to Southeast Asia. This study was conducted to determine the chemical composition of Japanese stiltgrass as well as soil and landscape characteristics that correlate with invasion of Japanese stiltgrass around Lake Issaqueena in the upper Piedmont of South Carolina. Geographic Information Systems (GISs) and Light Detection and Ranging (LiDAR) were used to determine the spatial pattern of invasion with respect to the aspect, slope, canopy cover, soils, and distance to roads and trails. Japanese stiltgrass was distributed on both sides of Lake Issaqueena in Pacolet and Madison soil map units (Fine, kaolinitic, thermic Typic Kanhapludults) on the average slopes of 21%, but it was particularly common on the eastern shore of the lake in low-lying wet and shaded areas (mean canopy cover 51%). In addition, invasion by Japanese stiltgrass was correlated with the proximity to roads and trails. Plant tissue analysis revealed many differences in the distribution of macronutrients, macrominerals, and micronutrients in the leaves, stems, and roots of Japanese stiltgrass, although those differences were not always statistically significant. Concentrations of nitrogen (N), phosphorus (P), and calcium (Ca) were the highest in leaves while zinc (Zn) concentrations were the highest in stems and concentrations of magnesium (Mg), copper (Cu), manganese (Mn), iron (Fe), and sodium (Na) tended to be higher in roots. Carbon (C), sulfur (S), and potassium (K) concentrations were generally higher in above-ground tissues versus roots. Soil chemical analysis revealed no statistical differences between control and invaded plots. Our findings suggest that watershed areas surrounding lakes may be particularly susceptible to the invasion of Japanese stiltgrass due to their microclimates, low-lying wet pathways for seed distribution and recreational uses.

Investigations into the Causes and Control of the Growth Arrestment Phenomenon of Sultana. II. Preliminary Experimental Investigations

As a continuation of the investigation into the growth abnormalities, called 'growth arrestment phenomenon' (GAP), which occur extensively in the Sultana vineyards of the Lower Orange River region, field experiments comprising K fertilisation, scheduled irrigation, crop control and specific plant organ and tissue analyses were conducted. Experimental results showed no response to K fertilisation but a promising response to controlled irrigation. Analyses of various organs revealed a faulty carbohydrate metabolism and high N concentrations, probably a result of the fertile soil and high temperatures during the growing season, causing vigorous as well as continued shoot growth after harvest. Specific analyses of affected organs and tissues showed black bunches and shiny spots on leaves to be high in N and Mn and low in K. It is postulated that amongst the major factors causing GAP are the specific climatic and soil conditions which cause poor accumulation of reserves and high N contents. The mechanism by which GAP is caused and practical measures to combat this phenomenon merit urgent further studies.

Stable carbon isotope analysis of Cedrus atlantica pollen as an indicator of moisture availability

Stable carbon isotope analysis of pollen provides potential for reconstruction of past moisture availability in the environment on longer time-scales compared to isotope analysis of plant tissue. Here we show that the carbon isotopic compositions (δ13C) of pollen, sporopollenin, leaf and stem tissues of Cedrus atlantica are strongly related. Untreated pollen δ13C has a significant linear relationship with sporopollenin δ13C (r2=0.97, p<0.0001) which is relatively depleted in 13C by an average 1.5‰. Carbon isotope discrimination (Δ13C) by sporopollenin (derived from pollen δ13C values) is related to mean annual (r2=0.54, p<0.001) and summer precipitation (r2=0.63, p<0.0001). A 100mm increase in mean annual precipitation results in sporopollenin Δ13C increasing by 0.52‰, or by 1.4‰ per 100mm summer precipitation. There is a stronger relationship between sporopollenin Δ13C and long-term annual scPDSI (r2=0.86, p<0.0001) and summer scPDSI (r2=0.86, p<0.001) aridity indexes, with reduced Δ13C as aridity increases. These relationships suggest that stable carbon isotope analysis of C. atlantica fossil pollen could be used as a quantitative proxy for the reconstruction of summer moisture availability in Northwest Africa.

A Review of Mid-Infrared and Near-Infrared Imaging: Principles, Concepts and Applications in Plant Tissue Analysis.

Plant cells, tissues and organs are composed of various biomolecules arranged as structurally diverse units, which represent heterogeneity at microscopic levels. Molecular knowledge about those constituents with their localization in such complexity is very crucial for both basic and applied plant sciences. In this context, infrared imaging techniques have advantages over conventional methods to investigate heterogeneous plant structures in providing quantitative and qualitative analyses with spatial distribution of the components. Thus, particularly, with the use of proper analytical approaches and sampling methods, these technologies offer significant information for the studies on plant classification, physiology, ecology, genetics, pathology and other related disciplines. This review aims to present a general perspective about near-infrared and mid-infrared imaging/microspectroscopy in plant research. It is addressed to compare potentialities of these methodologies with their advantages and limitations. With regard to the organization of the document, the first section will introduce the respective underlying principles followed by instrumentation, sampling techniques, sample preparations, measurement, and an overview of spectral pre-processing and multivariate analysis. The last section will review selected applications in the literature.

NUTRITIONAL DIAGNOSIS IN HYBRID COCONUT CULTIVATED IN NORTHEASTERN BRAZIL THROUGH DIAGNOSIS AND RECOMMENDATION INTEGRATED SYSTEM (DRIS)

ABSTRACT The assessment of the nutritional status of plants by leaf diagnosis such as the Diagnosis and Recommendation Integrated System (DRIS) has stood out among traditional methods of interpreting the results of plant tissue analysis. For coconut, nutritional monitoring through foliar analysis has been pointed as an efficient method for fertilizer recommendation, and the results have been traditionally interpreted using the critical level of sufficiency ranges criteria. The aim of this study was to evaluate the nutritional status and establish nutritional standards for the cultivation of hybrid coconut in the municipality of Moju, Pará, using DRIS. The leaf analysis and productivity results of 134 observations for the period 2001-2011 were used to form the database. The most common deficiencies found were lack of K, and possibly excess of Mg. The order of nutrient limitation was K&gt; P&gt; Ca&gt; Fe&gt; N&gt; O&gt; B&gt; Zn&gt; Cu&gt; Mn&gt; Mg. Ca, Fe and K nutrients are more likely to positively respond to fertilization, since Mg, Cu and Mn were diagnosed as having the greatest likelihood of negative response to fertilization. It was also found that N and P are elements that are in the best nutritional balance condition. Regression equations for the relationship between nutrient content in hybrid coconut leaves and its DRIS indexes were adjusted, which allowed establishing nutrient reference values based on DRIS.

Diagnosis and Recommendation Integrated System (DRIS) approach on Nutritional Diagnosis in Fruit crops- A Review

Diagnosis and Recommendation Integrated System (DRIS) is widely used statistical approach for interpretation of the plant tissue analysis data and to diagnose the plant nutreint needs much earlier than the reduction of crop yield with greater accuracy. It helps in simultaneous identifying imbalances, deficiencies and excesses of crop nutrients and ranks them in the order of their importance for their remedial steps. The DRIS norms based on foliar composition can developed in any crop and at any stage of its development. It provides a mathematical means of ordering large number of nutrient ratios into nutrient indices that can be easily interpreted. The nutrient ranges been established as deficient, low, optimum, high and excessive based on the mean of nutrient concentration and standard deviation from high yielding population to serve as a guide for a quick and routine diagnostic and advisory purpose. The major advantage of DRIS lies in its ability to minimize the effect of variation in tissue age on diagnosis, which allows a choice of wider range of tissues than permissible under the conventional critical value approach. Thus, DRIS is holistic in nature for identification of nutrient imbalance in crops and formulation of nutrient management strategies for achieving higher yields.

In-Field, In Situ, and In Vivo 3-Dimensional Elemental Mapping for Plant Tissue and Soil Analysis Using Laser-Induced Breakdown Spectroscopy.

Sensing and mapping element distributions in plant tissues and its growth environment has great significance for understanding the uptake, transport, and accumulation of nutrients and harmful elements in plants, as well as for understanding interactions between plants and the environment. In this study, we developed a 3-dimensional elemental mapping system based on laser-induced breakdown spectroscopy that can be deployed in- field to directly measure the distribution of multiple elements in living plants as well as in the soil. Mapping is performed by a fast scanning laser, which ablates a micro volume of a sample to form a plasma. The presence and concentration of specific elements are calculated using the atomic, ionic, and molecular spectral characteristics of the plasma emission spectra. Furthermore, we mapped the pesticide residues in maize leaves after spraying to demonstrate the capacity of this method for trace elemental mapping. We also used the system to quantitatively detect the element concentrations in soil, which can be used to further understand the element transport between plants and soil. We demonstrate that this method has great potential for elemental mapping in plant tissues and soil with the advantages of 3-dimensional and multi-elemental mapping, in situ and in vivo measurement, flexible use, and low cost.

Effects of biochar and fertilizer management on sunflower (Helianthus annuus L.) feedstock and soil properties

ABSTRACTThe need for bioenergy is increasing with increase in global energy demand, and sustainable soil and fertilizer management practices for bioenergy feedstock production are gaining importance. In this greenhouse study, we evaluated the effects of biochar and fertilizer nitrogen on soil and energy crop sunflower (Helianthus annuus L. var. Giganteus). Sunflower plants were treated with three rates of biochar, control (0 Mg ha−1), low (25 Mg ha−1) and high (50 Mg ha−1), and three rates of fertilizers, 0% (control), 50% (low) and 100% (high) of the recommended nitrogen dose. Plant height, quality (chlorophyll content), biomass yield, feedstock energy, ash content and tissue nutrients were measured along with soil moisture and pH. Results showed an 11% increase in mean plant height under low biochar compared to control biochar-treated plants. High nitrogen treatment produced 26% and 18% more stalk and total above-ground plant (whole plant) biomass, respectively, compared to the control nitrogen treatment. High biochar treatment resulted in higher soil moisture holding, but lower soil pH than the control biochar treatment. Plant quality, energy and ash contents were not affected by either biochar or nitrogen. The plant tissue analysis provides a complete tissue macro- and micronutrient information on sunflower cultivar Giganteus, which was not done previously.

Chlorophyll meter – a decision-making tool for nitrogen application in wheat under light soils

Nitrogen (N) in plants is generally diagnosed by a soil test and plant tissue analysis. However, such analyses are costly in terms of time and money and are not easily accessible by researchers and extension workers, let alone farmers. Alternative cost-effective methods are required for rapid analysis of the N status of crops and to guide N management in wheat. The objective of this study was to assess whether the SPAD values using a leaf chlorophyll meter could be used to apply N at the maximum tillering (MT) stage of irrigated spring wheat grown under light soils of South Asia. Experiments were conducted over two years under light soils at the Wheat Research Centre (WRC), Dinajpur, Bangladesh. Treatments were 80, 100 and 120 kg N ha −1 , applied two-thirds as basal and one-third at the crown root initiation (CRI) stage along with additional 10, 20 and 30 kg N ha −1 (first year) and 0, 10, 20 and 30 kg N ha -1 (second year) at MT. Rates at MT were determined on the basis of SPAD values, which fell below the critical value of 37.5, recorded at 45 days after sowing (DAS). SPAD values recorded at 55 and 65 DAS were positively correlated with grain yield (GY), indicating that the application of extra N at MT influences wheat GY. Our results have two major implications: (i) SPAD values based on a leaf chlorophyll meter can be used for N application and (ii) extra 30 kg N ha -1 at MT is