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The SPAD-502 and the FieldScout CM 1000 chlorophyll meters were compared in their performance in diagnosing the nutritional status of plants. Leaves of a wide range of greenness were used to push the sensitivity of the tools to their limits. Both devices showed high reproducibility when used by different operators. The SPAD-readings were well-correlated with leaf nitrogen (N) concentrations, since leaves from heavily fertilized plants were not included in the sample population. The FieldScout-readings showed a marked saturation curve with the leaf N concentration, thus it cannot be used as a reliable N nutritional status index. The results also showed that the use of SPAD-502 in the diagnosis of the nutritional status of an orchard requires the establishment of specific critical concentrations for cultivars and sampling dates. The SPAD-502 appeared to have potential in the diagnosis of the nutritional status of the orchard for nutrients other than N. [ABSTRACT FROM AUTHOR]

A small-plot field experiment started in 2016 studied effect of drip irrigation on potato tuber yield and starch levels in the tubers. Two potato varieties with different vegetation periods (Monika, Jolana) were exposed to four drip irrigation intensity levels. They were non-irrigated controls and irrigated tubers with 60 %, 65 % and 70 % usable soil water capacity levels. The other studied parameter was represented by the effect of nitrogen fertilisation with the nitrogen nutrient added to the irrigation water (fertigation) in the course of the vegetation period in contrast to one-off application of the whole nitrogen dose before the potato planting. All irrigated variants in comparison to the non-irrigated controls showed 30-60 % yield increase. The effect of fertigation on yields was statistically insignificant. Starch levels in the tubers were mostly affected by the variety. The irrigated variants in comparison to the non-irrigated controls showed higher starch levels in the harvested tubers but the differences were statistically insignificant. [ABSTRACT FROM AUTHOR]

Study aims to investigate the effects of vermicomposts containing oil processing wastes, dairy manure, municipal open market wastes and straw on the growth, nutrient concentrations and nutrient uptakes of corn plant. For this, there different mixtures were prepared. Vermicomposts were applied with the rates of 0, 5000, 10000, and 20000 kg ha−1 to 2 kg soil containing pots. Study was conducted in growth chamber for 2 months. Vermicompost applications increased plant growth, some plant nutrient concentrations and uptake. Also, vermicomposts showed the variation on parameters depending on their mixtures. Results showed that nutrients taken by the plant increased with the vermicompost until 10000 kg ha−1 dose. Most of the nutrient concentrations such as phosphorus, potassium, calcium, magnesium, iron, and manganese (P, K, Ca, Mg, Fe, and Mn) were not increased in plant tissues, whereas uptake of them by the plant showed a significant increase. In addition, residual soil nutrients increased with the increase in vermicompost levels. [ABSTRACT FROM AUTHOR]

Rice (Oryza sativa L.), a staple crop for over 50% of the world's population, is also a source of dietary arsenic (As) because of it's efficiencyat accumulating As. Lead–arsenate pesticide was used in agriculture, these soils potentially may be used for rice production. The objective of this study was to determine the effects of compost on total and inorganic As concentrations in rice grown on lead–arsenate contaminated soils. Three lead–arsenatesoils were amended with 10% by weight of compost and planted with rice under flooded and non-flooded conditions. Rice grain yieldwas higher with compost but not flooding. Flooding significantly increased total and inorganic As concentrations. In most cases, rice inorganic Asconcentrations were higher than the limit set by Chinaat 0.2 mg kg−1. Compost at therate used did not reduce rice grain As to safe levels.Lead–arsenate contaminated soils are not recommended for rice production. [ABSTRACT FROM AUTHOR]

A field experiment was conducted to assess the effect of microbial inoculants and inorganic fertilizers for sustaining the yield of soybean. Application of 100% recommended dose of fertilizer (RDF) gave significantly highest yield (2433 kg ha−1) over 75% RDF (2317 kg ha−1) and without RDF (2205 kg ha−1). Seeds inoculated with Rhizobium (Bradyrhizobium japonicum) and phosphate-solubilizing bacteria (2480 kg ha−1) gave significantly highest soybean yield over without inoculation (2191 kg ha−1). Rhizobium and phosphate-solubilizing bacteria with 100% RDF (2674 kg ha−1) gave significantly highest seed yield than rest of the treatment combinations. Root nodules and their dry weight were remained un-influenced due to fertilizer levels, whereas in bio-fertilizers, it was significantly higher with Rhizobium inoculation (24.3 and 408 mg, respectively) followed by dual inoculation of Rhizobium and PSB. 100% RDF and dual inoculation with Rhizobium and PSB earned Rs. 47916/- and Rs. 51182/- net returns per ha, respectively. [ABSTRACT FROM AUTHOR]

Increasing nitrogen use efficiency (NUE) in irrigated corn production is of great importance to overall agricultural sustainability. Studies have shown that crop canopy sensors can aid in this pursuit as they allow for the determination of nitrogen (N) requirements in split applications later in the growing season. Fertigation can also increase NUE as many split applications can be conducted. If crop canopy sensors could be used to direct N fertigation rates, overall NUE may be increased even further. However, in some cases, N differences may need to be determined later in the growing season after corn has tasseled, which can cause issues with crop canopy sensor readings. Therefore, a study was initiated to evaluate the potential of a crop canopy sensor to differentiate between N levels at two corn (Zea mays) growth stages (R1 and R3) after the corn had tasseled. The sensor was placed in three orientations to evaluate which orientation best determined the corn N status across two sensor-calculated indices while avoiding taking measurements involving the corn tassel. These orientations were (1) nadir, between corn rows (above canopy), (2) 45° off nadir within the corn canopy (below corn tassel), and (3) 90° off nadir within the corn canopy (below corn tassel). The results of this study show that N differences in late season corn can be determined by utilizing crop canopy sensors in an inter-row orientation. Results also show that the red edge normalized difference vegetation index (ReNDVI) index is superior to the normalized difference vegetation index (NDVI) index for late season N determinations in corn. These results suggest that crop canopy sensors could be an effective tool for determining N requirements of corn late in the growing season. [ABSTRACT FROM PUBLISHER]

Cobalt (Co) is beneficial for legume plants and not an essential element for most plants. There is no sufficient information about the effect of Co stress on barley growth. The current experiment was carried out to investigate the effects of different Co levels (25, 50, 75, and 100 µM) on growth and physiological traits of three barley genotypes (B325, J36, and B340) differing in Co tolerance. The results showed that Co stress inhibited plant growth, decreased chlorophyll content and photosynthetic rate, and enhanced oxidative stress. However, the effects differed among genotypes, with B325 and B340 being the most and the least affected, respectively. Co stress caused decrease and increase of manganese (Mn) and phosphorus (P) concentrations in both roots and shoots, respectively; iron (Fe) concentration had little change in shoots and a significant decrease in roots. The current results showed a close association of Co tolerance and its accumulation in plant tissues. [ABSTRACT FROM PUBLISHER]

Citric acid is a low-molecular-weight organic acid exuded by the plant roots. Organic anions derived from this acid compete for phosphorus (P) adsorption sites in clay minerals. The objective was to evaluate the P availability by application of P and citric acid tothe soil. For this purpose, an experiment in green house was conducted at the rates of 0, 45, 90, and 180 mg dm−3 P in Entisol and 0, 100, 200, and 400 mg dm−3 P in Oxisol, combined with 0, 0.5, 1.0, and 2.0 mg dm−3 citric acid in pot. In the Entisol, 115 mg dm−3 of P and 0.7 mg dm−3 of citric acid resulted in maximum corn growth. However, in the Oxisol, the estimated rates were 299 mg dm−3 of P and 1.3 mg dm−3 of acid citric. Citric acid use in Entisol and Oxisol increased P availability of corn plants. [ABSTRACT FROM AUTHOR]

A pot culture experiment was performed to study the effect of cadmium stress (Cd stress) on seedling growth, physiological traits, and remediation potency of Avena fatua, Lathyrus sativus, and Lolium temulentum. The seedlings of these native rangeland plant species were treated with 0, 2, 4, and 6 mM cadmium nitrate concentrations. Based on the results of analysis of variance (p < 0.05), the shoot height, shoot dry weight, root length, root dry weight, root: shoot ratio, total chlorophyll content, soluble sugars, and protein contentof A. fatua, L. sativus, and L. temulentum significantly decreased with increased cadmium concentrations. Generally, translocation factor (TF) and tolerance index (TI) decreased significantly as the concentration of cadmium increased. The maximum TF and TI of studied plants in various concentrations of Cd were observed in L. temulentum followed by L. sativus and A. fatua. The root concentration factor (RCF) values of all studied plants were higher than 1 under different cadmium concentrations. Our results indicate that Lolium temulentum could be labeled as an accumulator of Cd asthe values of TF and RCF are greater than 1. A. fatua and L. sativus showed a potential to be used in the phytoremediation of Cd-contaminated soils. [ABSTRACT FROM AUTHOR]

Minimizing salinity impacts on yield in melon crops cultivated in closed-loop hydroponic systems requires better understanding of the physiological impact of gradual salt accumulation in the recycled solution. To attain this objective, different sodium chloride (NaCl) concentrations in the irrigation water, i.e. 0.7, 2.5, and 5 mM, were applied in two cropping seasons (winter-spring;WS and spring-summer;SS). In both seasons plant biomass and yield were negatively affected only in high NaCl-treated plants, due to stomatal limitations, which restricted carbon dioxide (CO2) diffusion into the leaf, osmotic and salt-specific effects. However, a progressive NaCl built-up to maximum concentrations in the root zone solution of 15 (WS) and 20 mM (SS), enabled plants to preserve several physiological mechanisms, thereby adjusting growth and yield without impairing fruit quality. Our results suggest that the use of irrigation water, containing up to 2.5 mM NaCl, is feasible in melon crops grown in closed-loop hydroponic systems, without yield and quality losses. [ABSTRACT FROM PUBLISHER]

The objective of this study was to evaluate the effects of organic and inorganic fertilizers on the yield and quality of sugar beet genotypes (Beta vulgaris L.). Therefore, a field trial was carried out in Peshawar, Pakistan, during the winters in 2012–2013. The field experiment was conducted in a randomized complete block design with split plots, having three replications. Fertilizer treatments (control, composted manure Higo Organic Plus at 5 t ha−1, Maxicrop Sea Gold seaweed extract at 5 L ha−1, farm yard manure at 10 t ha−1, inorganic nitrogen–phosphorus (NP) at 90:60 kg ha−1, NP at 120:90 kg ha−1 and NP at 150:120 kg ha−1) were allotted to main plots, while genotypes (Sandrina, Serenada and Kawe Terma) were allotted to the sub-plots. Plots treated with the application of NP at 120:90 kg ha−1 produced the highest beet yield (76.4 t ha−1) and sugar yield (11.1 t ha−1), and had the second highest polarizable sugar content (14.52%) and more economic return (Rs. 553,000 per hectare) as compared to control plots. Sugar beet genotype Serenada had significantly higher beet yield (55.5 t ha−1) and sugar yield (7.9 t ha−1) and a higher economic return (Rs. 380,000 per hectare) than the other genotypes. Sugar beet genotype Serenada supplied with NP at 120:90 kg ha−1is recommended for the general cultivation in the agro-climatic conditions of Peshawar valley. [ABSTRACT FROM AUTHOR]

Volcanic mountains in the East African Rift ( e.g. Mt. Kenya, Mt. Kilimanjaro, Mt. Elgon) are some of the most productive agricultural regions, often dominated by coffee and banana cultivation. Consequently, these regions suffer from a high and increasing population density with a declining soil fertility status imposing pressure on the available land, which in turn results in encroaching into the national forests. This study documents the soil fertility constraints along the slopes of Mt. Elgon and explores its corresponding gradients in plant nutritional status. This research links the topography of Mt. Elgon to the prevailing soil types and their current fertility status. It reveals important relations and gradients between soil fertility parameters and its corresponding environment along the slope. Soil pH, soil available P and exchangeable K, Ca and Mg are significantly decreasing with elevation. Thereby, gradients and constraints in macro- and micro-nutrient uptake by coffee and banana are revealed along the toposequence and different altitude-specific nutrient limitations are determined for both crops. K, Mn and Si uptake in both crops is decreasing with elevation along the slope, while the Mo and Ni uptake in both crops is increasing. With increasing elevation, B uptake is only decreasing in coffee and P uptake is only decreasing in banana. In addition, the antagonistic interaction between K and Mg limits the Mg uptake of both crops in the lower areas, while in the high region the Mg uptake is simply limited by low soil availability. It follows that a general fertilizer recommendation cannot be made in these regions and that the soil fertility problems along these slopes should be specifically addressed and appropriately managed according to the local requirements. [ABSTRACT FROM AUTHOR]

Arbuscular mycorrhizal (AM) fungi are present in all soils and comprise an important component of soil biota with respect to plant nutrition and growth as well as soil quality. Previous research in a number of agroecosystems had documented large impacts from various management practices (e.g., tillage, fertilization, crop rotation) on the levels of host root colonization and/or composition of the AM fungal communities in the roots and soil. Here, we tested whether a standardized mycorrhizal bioassay could contribute to deciphering soil-use legacy through detection of consistent changes in the colonization pattern of a mycorrhizal bait plant (leek). To this end, we grew the leek in a large number (154) of soils under uniform environmental conditions. Most of the variation in the mycorrhizal colonization of bait plants grown in the different soils could be attributed to soil properties and sampling site altitude, whereas the occurrence of specific structures (vesicles) was particularly correlated with abundance of certain AM fungal taxa such as Rhizophagus sp. Contributions of the root colonization of bait plants to explaining agricultural management practices and soil heavy metal concentrations (frequently used as indicators of soil quality) were comparatively small and partly counterintuitive. For example, higher incidence of arbuscules was detected in soils to which mineral fertilizers were applied as compared to organically farmed soils. Moreover, the explanatory power of the bioassay was much less than was that for soil respiration, a well established bioindicator of soil quality. Therefore, the mycorrhizal bioassay tested here appears not to be suitable as an interpreter of soil-use legacy, even though it does uncover very clear trends in colonization patterns of the bait plants by indigenous AM communities across large environmental gradients. [ABSTRACT FROM AUTHOR]

The monovalent cation proton antiporters (CPAs) play essential roles in plant nutrition, development, and signal transduction by regulating ion and pH homeostasis of the cell. The CPAs of plants include the Na/H exchanger, K efflux antiporter, and cation/H exchanger families. However, currently, little is known about the CPA genes in Rosaceae species. In this study, 220 CPA genes were identified from five Rosaceae species ( Pyrus bretschneideri, Malus domestica, Prunus persica, Fragaria vesca, and Prunus mume), and 53 of which came from P. bretschneideri. Phylogenetic, structure, collinearity, and gene expression analyses were conducted on the entire CPA genes of pear. Gene expression data showed that 35 and 37 CPA genes were expressed in pear fruit and pollen tubes, respectively. The transcript analysis of some CPA genes under abiotic stress conditions revealed that CPAs may play an important role in pollen tubes growth. The results presented here will be useful in improving understanding of the complexity of the CPA gene family and will promote functional characterization in future studies. [ABSTRACT FROM AUTHOR]

Nutrition diagnosis plays a key role in the crop's growth, which has mainly been carried out in the field by agricultural workers. Currently, automatic nutrition recognition technologies have been widely used in this field. A procedure is proposed in this paper to diagnose nitrogen nutrition non-destructively for rapeseed qualitatively based on the multifractal theory. Twelve texture parameters are given by the method of multifractal detrended fluctuation (MF-DFA), which contains six generalized Hurst exponents and six relative multifractal parameters that are used as features of the rapeseed leaf images for identifying the two nitrogen levels, namely, the -mezzo and the -wane. For the base leaves, central leaves and top leaves of the rapeseed plant and the three-section mixed samples, three parameters combinations are selected to conduct the work. Five classifiers of Fisher's linear discriminant algorithm (LDA), extreme learning machine (ELM), support vector machine and kernel method (SVMKM), random decision forests (RF) and -nearest neighbor algorithm (KNN) are employed to calculate the diagnosis accuracy. An interesting finding is that the best diagnose accuracy is from the base leaves of the rapeseed plant. It is explained that the base leaf is the most sensitive to the nitrogen deficiency. The diagnose effect by the base leaves samples is outshining the existing result significantly for the same leaves samples. For the mixed samples, the averaged discriminant accuracy reaches 97.12% and 97.56% by SVMKM and RF methods with the -fold cross-validation respectively. The resulting high accuracy on -levels identification shows the feasibility and efficiency of our method. [ABSTRACT FROM AUTHOR]

Integrated Plant Nutrition System (IPNS) as a concept and farm management strategy embraces and transcends from single season crop fertilization efforts to planning and management of plant nutrients in crop rotations and farming systems on a long-term basis for enhanced productivity, profitability and sustainability. It is estimated that about two-thirds of the required increase in crop production in developing countries will have to come from yield increases from lands already under cultivation. IPNS enhances soil productivity through a balanced use of soil nutrients, chemical fertilizers, combined with organic sources of plant nutrients, including bio-inoculants and nutrient transfer through agro-forestry systems and has adaptation to farming systems in both irrigated and rainfed agriculture. Horticultural crops, mainly plantation crops, management practices include application of fertilizers and pesticides which become inevitable due to the depletion of soil organic matter and incidence of pests and diseases. The extensive use of chemical fertilizers in these crops deteriorated soil health that in turn affected the productivity. To revitalize soil health and to enhance productivity, it is inexorable to enrich the soil using microorganisms. The lacunae observed here is the lack of exploitation of indigenous microbes having the potential to fix atmospheric nitrogen (N) and to solubilize Phosphorus (P) and Potassium (K). The concept of biofertilizer application appears to be technically simple and financially feasible, but the task of developing biofertilizers with efficient strains in appropriate combinations in a consortia mode is not easier. More than developing consortia, a suitable delivery system to discharge the microbial inoculants warranted much effort. This review focuses on the integrated plant nutrition system incorporating biofertilizer with special emphasis on developing and formulating biofertilizer consortium. [ABSTRACT FROM PUBLISHER]

Female herbivorous insects often dictate the distributions of offspring through oviposition site selection. The optimal oviposition hypothesis proposes that sites selected should benefit offspring because they provide the best diets, but distributions can reflect adult responses to non-dietary factors. On its dioecious host [ Allocasuarina verticillata (Lam.) L. Johnson ( Casuarinaceae)], the largely sessile nymphs of Aacanthocnema dobsoni ( Froggatt) ( Hemiptera: Triozidae) are most abundant at the bases of the equisetoid, photosynthetic branchlets and can also be associated with chlorosis. We asked whether the distribution of nymphs could be explained by the nutritional quality of hosts (at tree and branchlet levels) and investigated the nutritional implications of chlorosis. Binary choice oviposition bioassays revealed that female psyllids exhibited a weak preference for the apical (younger) halves of branchlets of male and female trees over basal (older) halves. In the absence of nymphs, basal and apical halves of branchlets of both sexes had comparable concentrations of amino N. The severity of chlorosis of individual female branchlets was positively related to the density of nymphs. Along entire female branchlets, chlorosis was associated with significant reductions in the concentrations of certain amino acids (including glutamic acid). For basal halves of female branchlets, chlorosis was associated with increased concentrations of a different suite of amino acids, i.e., evidence of nutritional enhancement. Fifth instars from female branchlets were slightly larger than those from male branchlets but nymphal morphology is constrained by branchlet diameter. The conformation of the host (especially the spaces between the scale-like leaves) appears to dictate oviposition site selection more than nutritional quality. Nutritional enhancement is suggested to explain the absence of a strong linkage between preference and performance. Aggregation of adults (and eggs) at the base of branchlets could arise from heightened risk of dislodgement by wind at the ends of branchlets and enhanced mate finding in less exposed locations. [ABSTRACT FROM AUTHOR]

The plant root system traverses one of the most complex environments on earth. Understanding how roots support plant life on land requires knowing how soil properties affect the availability of nutrients and water and how roots manipulate the soil environment to optimize acquisition of these resources. Imaging of roots in soil allows the integrated analysis and modeling of environmental interactions occurring at micro- to macroscales. Advances in phenotyping of root systems is driving innovation in cross-platform-compatible methods for data analysis. Root systems acclimate to the environment through architectural changes that act at the root-type level as well as through tissue-specific changes that affect the metabolic needs of the root and the efficiency of nutrient uptake. A molecular understanding of the signaling mechanisms that guide local and systemic signaling is providing insight into the regulatory logic of environmental responses and has identified points where crosstalk between pathways occurs. [ABSTRACT FROM AUTHOR]

Nepenthes pitcher plants display interspecific diversity in pitcher form and diets. This species-rich genus might be a conspicuous candidate for an adaptive radiation. However, the pitcher traits of different species have never been quantified in a comparative study, nor have their possible adaptations to the resources they exploit been tested. In this study, we compare the pitcher features and prey composition of the seven Nepenthes taxa that grow in the heath forest of Brunei (Borneo) and investigate whether these species display different trapping syndromes that target different prey. The Nepenthes species are shown to display species-specific combinations of pitcher shapes, volumes, rewards, attraction and capture traits, and different degrees of ontogenetic pitcher dimorphism. The prey spectra also differ among plant species and between ontogenetic morphotypes in their combinations of ants, flying insects, termites, and noninsect guilds. According to a discriminant analysis, the Nepenthes species collected at the same site differ significantly in prey abundance and composition at the level of order, showing niche segregation but with varying degrees of niche overlap according to pairwise species comparisons. Weakly carnivorous species are first characterized by an absence of attractive traits. Generalist carnivorous species have a sweet odor, a wide pitcher aperture, and an acidic pitcher fluid. Guild specializations are explained by different combinations of morpho-functional traits. Ant captures increase with extrafloral nectar, fluid acidity, and slippery waxy walls. Termite captures increase with narrowness of pitchers, presence of a rim of edible trichomes, and symbiotic association with ants. The abundance of flying insects is primarily correlated with pitcher conicity, pitcher aperture diameter, and odor presence. Such species-specific syndromes favoring resource partitioning may result from local character displacement by competition and/or previous adaptations to geographically distinct environments. [ABSTRACT FROM AUTHOR]

Potassium (K) is a major element for proper plant nutrition in addition to nitrogen and phosphorus. Soil 2:1 clay minerals serve as a K reservoir for plants because they can fix anhydrous K + ions in their interlayer sites (formation of “illite-like” layers) and such “fixed” ions can nonetheless be taken up by plants. The objective of the study was to determine if modifications of the illite structure can be observed within one season of maize growth and if these changes are impacted by fertilization and Arbuscular Mycorrhizal Fungi (AMF) inoculation. To do so, clay fractions recovered from (1) soil adhering to maize roots (“rhizosphere” soil), (2) soil sampled in the vicinity of maize roots but not adhering to the roots (“non rhizosphere” soil) and (3) soil sampled in adjacent un-planted fallow soil (“fallow” soil) were investigated using X-ray diffraction. The results indicated that extraction of K occurs during growth of the plants (40 days after sowing) and modifies the illite structure differently in the rhizosphere compared to the soil not adhering to the roots. At the end of the growth period (130 days) more K was present in the clay minerals than after 40 days growth except in the rhizosphere of AMF-inoculated roots, showing that mycorrhiza activity tended to affect a slightly greater loss of K compared to non-mycorrhiza clays in the rhizosphere. No influence of K fertilization on soil clay illite structure was observed suggesting that added K has been either already been taken up by maize plants after 40 days, either leached or adsorbed elsewhere than in the 2:1 clay mineral interlayer sites (organic matter or external sites). The results showed that clay modifications can be observed at the scale of a growing season and suggest that K + ions can be extracted by the plants from the illitic layers (in illite minerals and illite layers of mixed layered smectite/illite minerals) and re-stored (being lost from plants and returning to the soil) within one growing season. [ABSTRACT FROM AUTHOR]

Roots are vital to plant anchorage and efficient uptake of water and nutrients, and play an important role in environmental fitness, performance and yield formation in crops. The main objective of this study was to dissect the developmental behavior of seedling root traits at different developmental stages, and try to explore stress effect of nitrogen deficiency at seedling stage by mapping quantitative trait loci (QTLs) using an intraspecific population of recombinant inbred lines in Upland cotton ( Gossypium hirsutum L.). Totally, 34 QTLs and 27 conditional QTLs for root length, root surface area, root volume, number of root tips and number of root forks were detected, respectively, in which 18 were congruent QTLs. The performance of five seedling root traits and QTLs showed obvious dynamic characteristics at three developmental stages. Special conditional QTLs were detected by QTL mapping strategy, in which conditional QTLs with different effects were identified at certain stages, demonstrating that the expression of genes showed temporal characteristics during root development. After nitrogen deprivation and deficiency stress for five days, a total of 11 QTLs were identified. Of these, ten QTLs were also identified in previous three stages under normal nutritional condition, and one QTL qNRT- chr19- 1 referring number of root tips was newly detected, which suggested that it might be related to stress response of N-deficiency. After nitrogen deprivation for eight days, a total of 5 QTLs for plant height, maximum root length, fresh weight of root, and root/shoot ratio were identified. These QTLs and dynamic QTLs might offer different clues to understand the developmental mechanism and genetic basis of seedling root traits and to select root trait architecture in breeding program of Upland cotton. [ABSTRACT FROM AUTHOR]

This paper refers on the yields and productive aspects of mineral and foliar nutrition of globe artichoke plants (cv. ‘Opal’ and ‘Madrigal’). Marketable yields were investigated in response to different nitrogen rates and foliar applications of biostimulating products. Field experiments were conducted over two seasons on an alluvial salty-clay soil in sub-humid climate conditions. Analyzed traits differed between years because of the age of plants while the lowest nitrogen rate and foliar spraying of biostimulants influenced significantly head weight, dry matter, and Soil Plant Analysis Division (SPAD) index. Biostimulants induced longer cultural cycle and heads lighter in weight. Cultivar ‘Madrigal’ was most productive than ‘Opal’, both in number (26.28% higher) and in weight (28.51%) of total heads. The two-year investigation showed that the synergic action was effective in improving some of the investigated productive traits of globe artichoke. [ABSTRACT FROM PUBLISHER]

Deviation from optimum percentage (DOP) and Diagnosis and Recommendation Integrated System (DRIS) are methodologies for leaf analysis interpretation. DOP calculates the deviation as a percentage for each essential element while DRIS calculates the average deviation for different ratios that include each element. A vine survey was undertaken for 11 years in La Rioja, northeastern Spain, to establish nutritional references for cv. ‘Tempranillo’ (Vitis vinifera L.). Diagnosis of nitrogen, phosphorus, potassium, calcium, and magnesium were performed by DRIS and DOP on the dataset for leaf blade and petiole, at both flowering (n = 684) and veraison (n = 801) with a moderate-yield criterion (3,800–10,000 kg·ha−1). Important differences between DOP and DRIS were found when a diagnosis using the same dataset was performed. In spite of the differences, the regression equations obtained are an acceptable adjustment between both methods for phosphorus (P) and magnesium (Mg) in blades and petioles, and for potassium (K) in blades. [ABSTRACT FROM AUTHOR]

Arbuscular Mycorrhizal Fungi (AMF) constitute a group of root obligate biotrophs that exchange mutual benefits with about 80% of plants. They are considered natural biofertilizers, since they provide the host with water, nutrients, and pathogen protection, in exchange for photosynthetic products. Thus, AMF are primary biotic soil components which, when missing or impoverished, can lead to a less efficient ecosystem functioning. The process of re-establishing the natural level of AMF richness can represent a valid alternative to conventional fertilization practices, with a view to sustainable agriculture. The main strategy that can be adopted to achieve this goal is the direct re-introduction of AMF propagules (inoculum) into a target soil. Originally, AMF were described to generally lack host- and niche-specificity, and therefore suggested as agriculturally suitable for a wide range of plants and environmental conditions. Unfortunately, the assumptions that have been made and the results that have been obtained so far are often worlds apart. The problem is that success is unpredictable since different plant species vary their response to the same AMF species mix. Many factors can affect the success of inoculation and AMF persistence in soil, including species compatibility with the target environment, the degree of spatial competition with other soil organisms in the target niche and the timing of inoculation. Thus, it is preferable to take these factors into account when "tuning" an inoculum to a target environment in order to avoid failure of the inoculation process. Genomics and transcriptomics have led to a giant step forward in the research field of AMF, with consequent major advances in the current knowledge on the processes involved in their interaction with the host-plant and other soil organisms. The history of AMF applications in controlled and open-field conditions is now long. A review of biofertilization experiments, based on the use of AMF, has here been proposed, focusing on a few important factors that could increase the odds or jeopardize the success of the inoculation process. [ABSTRACT FROM AUTHOR]

In tropical areas very few studies have analyzed wetlands' ability to control nutrients. We analyzed the efficiency of the Pátzcuaro subtropical wetland in Mexico to retain nutrients (total phosphorus: TP; soluble reactive phosphorus: PO4 3-, nitrite: NO2 - and nitrate: NO3 -) and total suspended solids (TSS) and its temporal variability from November 2011 to October 2012, where two hydrological different periods (dry and wet periods) were included. The results indicate that, annually, this wetland reduced TP, 30.4%; PO4 3-, 19.2%; NO2 -, 2.5%; NO3 -, 17.6%; and TSS, 14.7%. However, the reduction% rose to 55.3% for TP and to 47.3% for PO4 3- during the dry period and to 14.1% for NO2 -, 49% for NO3 - and 44.5% for TSS during the rainy period. These results show dependence on the hydrological cycle, although P retention is also related with uptake by a dense macrophyte community and with organic matter accumulation. The results obtained suggest that removal of N is due mainly to denitrification. TSS retention seems to respond to low speed hydraulics and the resistance generated by macrophytes roots and floating plants. Like other studies in temperate environments, this wetland seems to remove more efficiently P than N. Unlike that in temperate environments where the highest nutrient retention occurs in autumn, we found the highest retention values for both NO2 - and NO3 - during summer (rainy period), and the lowest for P, probably due to release of P for the senescence of wetland plants during this period. [ABSTRACT FROM AUTHOR]

The objectives were to determine the effect of different levels of foliar iron fertilization on the some physical properties and breakage susceptibility of wheat seed. Foliar iron treatments were combinations of three fertilization rates [0 (control), 1.2 and 2 L ha−1, Fusin] at three replications. The harvested seeds were then subjected to impact energies of 0.1 and 0.2 J, at moisture contents of 8.5, 15, 20 and 25% (w.b.), using an impact test apparatus. Results indicated that the values of the seed physical properties increased with increasing iron rate. Iron fertilizer rate, moisture content and the interaction between two variables significantly influenced breakage susceptibility of wheat seeds at the 1% probability level (P < 0.01). Resistance to the breakage of wheat seeds increased following a polynomial relationship with increase in the foliar iron rate. Increasing the rate of foliar iron from 0 to 2 L ha−1 caused a significant decrease in the mean values of damage by a factor of 1.8 from 66.188 to 36.688%. As the moisture content of the seeds increased from 8.5 to 25%, the amount of the percentage breakage of seeds decreased, as a polynomial. The maximum rate of decrease in the damage to seeds, with increasing moisture content, was obtained at higher iron fertilizer rates. [ABSTRACT FROM AUTHOR]

The objective was to differentiate and estimate phosphorus (P)-uptake and P-utilization efficiency among several winter wheat accessions. Twenty-two accessions were characterized for their ability to uptake and utilize P in two low P soils (acid and calcareous). Plants were grown for 28 days in two different sized pots and analyzed for biomass and total P concentration. Total P uptake and biomass was greater in the large pot and calcareous soil. However, there were no significant correlations between the small and large pot for biomass, P uptake, and P concentration, indicating that rooting conditions were different for the two pots, which allowed differentiation between P-utilization and P-uptake efficiency. Possession ofALTM1gene for malate excretion did not appear to be related to P-uptake efficiency. Several accessions were found to be either P-uptake or P-utilization efficient in both soils. Phosphorus use efficiency mechanisms may contribute to acid soil tolerance. [ABSTRACT FROM PUBLISHER]

It has been hypothesized that the uptake of organic as opposed to inorganic nitrogen compounds found in wastewater can be properly substituted for plant nutrients. The objective of this study was to compare effects of applying monosodium glutamate wastewater (MGW) and ammonium nitrate (NH4NO3) (AN) on nitrogen metabolism and growth of lettuce. The results showed that while NH4NO3 (AN), NO3-, nitrite content and NR activity increased the protein content of lettuce. Applying MGW with a high concentration of 17 amino acids and macro- and microelements improved the fresh weights of shoot and root as well as the protein content of lettuce. Antioxidant activities were not affected by AN and MGW, and their interaction effects only increased POD after 8 weeks. In conclusion, substituting a portion of the chemical fertilizers with MGW improved lettuce growth, but did not increase NO3- accumulation in leaves. [ABSTRACT FROM AUTHOR]

The approach to select new growing media, has been focused on selecting materials only from the physical point of view. The objective of this study was to describe the physiological mechanisms involved in I. wallerana growth when cropped on a broad range of growing media created from alternative components. Results showed a close relationship between I. wallerana growth and fine particle size at the beginning of the experiments. Shoot fresh weight was determined mainly by the root system size. There were small differences in the relative growth rate (RGR) between the control substrate and the thirty alternative substrates tested. The lower RGR values resulted from a decrease in the net assimilation rate and the leaf area ratio. The mechanism involved would be associated with a change in photosynthate partitioning, which favored root growth. A close relationship between growth (as total dry weight) and nitrogen content was found as well. [ABSTRACT FROM AUTHOR]

Evaluations of vegetative growth and leaf concentrations of nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), and iron (Fe) were made of apple (Malus domestica Borkh. cvs. Granny Smith, Gala, and Golab) grown with five treatments of NO3−:NH4+ ratios in pot culture. The concentrations of NO3−:NH4+ ratios were 2.5:0.1, 6:0.3, 6:0.5, 6:0.7, and 6: 1 meq L−1. Regression analysis showed that growth parameters of main stems and branches were not affected by increases of NH4+ in the ratios. Granny Smith, Gala, and Golab differed in some of these parameters. Concentrations of N and Fe increased as NH4+ increased, whereas K and Ca decreased and Mg was not affected significantly. Generally, the treatment of 2.5:0.1 produced leaves with lower N but higher K, Ca, and Mg concentrations than the other treatments. This research showed that vegetative growth was not affected by NH4+ concentration whereas elemental composition was affected. [ABSTRACT FROM AUTHOR]

Inadequate plant nutrition and biotic stress are key threats to current and future crop yields. Zinc (Zn) deficiency and toxicity in major crop plants have been documented, but there is limited information on how pathogen and pest damage may be affected by differing plant Zn levels. In our study, we used soybean plants as a host, a soybean pest, and three soybean pathogens to determine whether plant Zn levels change pest and disease assessments. Two soybean cultivars were grown in sand culture with a soluble nutrient solution that ranged from Zn-deficient to toxic. Detached leaves from these plants were either inoculated with Aphis glycines, the soybean aphid, Xanthomonas axonopodis pv. glycines, a bacterium that causes bacterial pustule, Sclerotinia sclerotiorum, the necrotrophic fungus responsible for stem rot, or Phakopsora pachyrhizi, a biotrophic obligate pathogen that causes soybean rust. There were significant (P < 5%) effects on aphid colonization, positive counts for bacterial pustule, S. sclerotiorum leaf area affected, and numbers of rust lesions associated with the Zn treatments. Plants grown with the physiologically optimal levels of Zn (2 μM) had less (P < 5%) soybean aphids cm–2 leaflet than plants grown without Zn, at 0.1× Zn (0.2 μM), or at 100× Zn fertilization (200 μM). Plants grown with the normal fertilization of Zn or 100× Zn had fewer (P < 5%) positive counts for bacterial pustule and less lesion area affected by S. sclerotiorum than plants grown without Zn or fertilized with 0.1× Zn. For soybean rust, plants grown with the physiologically optimal fertilization of Zn or 100× Zn had higher (P < 5%) lesions cm–2on leaflets from plants grown without Zn or fertilized with 0.1× Zn. These results indicate different Zn nutrition levels in soybean significantly affected aphid and disease development. [ABSTRACT FROM AUTHOR]

The rhizospheric bacteria play key role in plant nutrition and growth promotion. The effects of increased nitrogen inputs on plant rhizospheric soils also have impacted on whole soil microbial communities. In this study, we analyzed the effects of applied nitrogen (urea) on rhizospheric bacterial composition and diversity in a greenhouse assay using the high-throughput sequencing technique. To explore the environmental factors driving the abundance, diversity and composition of soil bacterial communities, the relationship between soil variables and the bacterial communities were also analyzed using the mantel test as well as the redundancy analysis. The results revealed significant bacterial diversity changes at different amounts of applied urea, especially between the control treatment and the N fertilized treatments. Mantel tests showed that the bacterial communities were significantly correlated with the soil nitrate nitrogen, available nitrogen, soil pH, ammonium nitrogen and total organic carbon. The present study deepened the understanding about the rhizospheric soil microbial communities under different amounts of applied urea in greenhouse conditions, and our work revealed the environmental factors affecting the abundance, diversity and composition of rhizospheric bacterial communities. [ABSTRACT FROM AUTHOR]

The leaf nutrient status and stoichiometry of nitrogen (N), phosphorus (P), and potassium (K) were determined for Elaeocarpus joga trees in Guam's dominant calcareous soils to understand nutrient limitations in limestone soils of Oceania and contribute to global databases on leaf economic spectrum studies. Supplemental N, P, or K was added to soils to determine plant growth and nutrient concentration responses. Leaf and soil quantifications of nutrients enabled multiple trait comparisons. Supplemental N stimulated growth of young cultivated plants without affecting leaf N concentrations. Supplemental K increased leaf K concentration but did not generate a growth response. Supplemental P did not affect growth or leaf P concentration. N:P, N:K, and K:P were most influenced by K additions. Leaf N and P concentrations of mature trees in unmanaged settings were similar to unfertilized young plants in the controlled study, but leaf K concentration was greater in the mature trees. Leaf nutrient relations were not overtly related to soil nutrient relations for mature trees. Results indicate that N and K are the limiting factors in calcareous soils of the Mariana Islands for this endemic tree species, age and size of trees do not greatly influence leaf nutrient content, and leaf stoichiometry is constrained and less variable than soil stoichiometry. [ABSTRACT FROM AUTHOR]

The effect of potassium sulfate (K2SO4) on adaptability of sugarcane to sodium chloride (NaCl) stress was investigated under hydroponic conditions. Two sugarcane cultivars, differing in salinity tolerance, were grown in half strength Johnson's solution at 80 mM NaCl with 0, 2.5 and 5.0 mM potassium (K) as K2SO4. Salinity disturbed above and below-ground dry matter production in both sugarcane cultivars. However, salt sensitive cultivar showed more reduction in shoot dry matter and higher root:shoot ratio compare to the salt tolerant cultivar under. Application of K significantly (p < 0.05) improved dry matter production in both sugarcane cultivars. The concentration of Na was markedly increased with increasing salinity; however, the application of K reduced its uptake, accumulation and distribution in plant tissues. Salinity induced reduction in K concentration, K-uptake, K utilization efficiency (KUE) and K:Na ratio in both sugarcane cultivars was significantly improved with the addition of K to the saline growth medium. [ABSTRACT FROM AUTHOR]

This study evaluated nutrient accumulation of yellow passion fruit seedlings produced in substrates containing proportions of decomposed buriti (Mauritia vinifera Mart.) stem (DBS) and the boron in this process. Four experiments were conducted in Federal University of Piauí in Brazil. The experimental design was completely randomized in factorial scheme 6 × 2 + 1, referring to the substrates [DBS (100%), soil and sand 1:1 (20%) + DBS (80%), soil and sand 1:1 (40%) + DBS (60%), soil and sand 1:1 (60%) + DBS (40%), soil and sand 1:1 (80%) + DBS (20%), commercial substrate (additional treatment without boron) and soil, sand and manure 1:1:2] with (0.5 mg B.dm−3) and without boron. The following variables were recorded: total nitrogen, total phosphorus, potassium, calcium and magnesium, boron, absorption efficiency index and chlorophyll. No influence concerning the substrate composition was noticed on nutritional status, but boron influenced on K and Mg of yellow passion fruit seedlings. [ABSTRACT FROM AUTHOR]

In order to reduce nutrient wastes to the environment the supply should be in accordance to the demand for these. Two experiments were conducted to study and quantify the effect of temperature, irradiance, and plant age on the uptake of nitrate (NO3−), ammonium (NH4+), dihydrogen phosphate ion (H2PO4−), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and sulfate (SO42). In the first experiment, various levels of temperature and irradiance were applied to plants in a growth chamber, while in the second experiment the uptake was studied along the crop season under greenhouse conditions. The uptake rates were calculated at 2-hour intervals through sampling the nutrient solution and analyzing it by inductively coupled plasma atomic emission spectrometry (ICP-AES). Increasing light and temperature enhance the uptake rates, while the rates decrease with plant age. Nitrogen absorption was similar during the day as during the night. No differences were found in the absorption of H2PO4−, K+, Ca2+, Mg2+, and SO42− between day and night. Nitrate absorption was found to have a positive correlation with the absorption of all the ions except for NH4+. [ABSTRACT FROM AUTHOR]

A field study was carried out to determine the ecological fitness of roselle (Hibiscus sabdariffa) within Alabama (USA) and assess the nutritional value for human and animal consumption. Two varieties of roselle, red drops and thai red, were seeded in late April 2013 and 2014. Gas exchange and quantum yield were not significantly different between varieties. Chlorophyll a, b and carotenoid were significantly higher in thai red than red drops. Anthocyamn was not significantly different in the calyces of the two varieties. Crude protein was similar in both varieties but significantly higher in the leaves. Neutral Detergent Fiber (NDF) concentration was significantly different between the selected plant parts of red drops, but thai red showed similar NDF concentration in the leaves and calyces. Acid Detergent Fiber (ADF) concentration was significantly different between the plant parts. In general, the macronutrient and micronutrient concentrations were similar between the two varieties. In conclusion, the two selected varieties of roselle can be considered a suitable crop to be established in the southern region of the US. Based on the overall nutrition assessment, roselle shoots can be also considered a good source for food. [ABSTRACT FROM AUTHOR]

While modernization of olive cultivation has recently lead to vast expansion of fully irrigated orchards, characterization of olive tree nutritional status remains based on knowledge gleamed from rain-fed orchards. In the present study, the effect of irrigation level on olive tree nutritional status was investigated in Israel over 4 years on two cultivars and in two locations characterized by differences in soil, tree age, management history, fertilizer application and irrigation water quality. Diagnostic leaves, sampled in July, were evaluated as indicators of nutritional status. Leaf nitrogen concentration was not affected by irrigation level. Leaf phosphorous and potassium concentrations increased with increasing irrigation level. Leaf calcium, manganese and iron tended to decrease with irrigation, while magnesium, sodium and zinc concentrations were not generally affected by irrigation level. Leaf boron and chloride concentrations increased with increasing irrigation when their concentration in irrigation water was relatively high. Leaf nutrient concentration was influenced by cultivar. The results presented in this study emphasize a strong link between irrigation level and the nutritional status of olives for some nutrients and no association for others. These findings should aid in developing distinct fertilization recommendations for fully irrigated olives, different from those developed and used for rain-fed or supplemental-irrigated orchards. [ABSTRACT FROM AUTHOR]

During 2013 and 2014 seasons Keitte mango trees subjecting four times to foliar application of fenugreek seed sprout at 0.5 to 2.0% singly or in various combinations with NPKMg at 0.5% and / or ZnFeMn at 0.05%. The study focused on the impact of these treatments on growth, nutritional status of the trees, yield as well as physical and chemical characteristics of the fruits. Spraying fenugreek seed sprout at 0.5 to 2% either alone or in combination with macro and/ or micronutrients was very effective in enhancing growth traits, tree nutritional status, yield and fruit quality rather than non- application. The promotion was associated with increasing concentrations of fenugreek seed sprout. Using fenugreek seed sprout was superior than using all nutrients in this respect. Combined application of fenugreek seed sprout as well as macro and micronutrients was materially favourable than using each one alone in improving fruiting of such mango cv. The best results with regard to growth, tree nutritional status, yield and fruit quality of Keitte mango trees grown under Aswan region conditions were obtained due to using a mixture of fenugreek seed sprout at 1% besides NPKMgat 0.5% and Zn Fe Mn at 0.05% four times. [ABSTRACT FROM AUTHOR]

The objective was to evaluate the effects of omitting macronutrients in the nutrients solution on growth characteristics and nutritional status of eggplants. The treatments were complete nutrients solution and solutions with nutrient omission: nitrogen (N), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), and sulfur (S). The experiment was carried out under greenhouse conditions with three replicates in a completely random design. Plant height, number of leaves per plant, leaf area, relative chlorophyll index, photosynthesis rate, stomatal conductance, dry matter, concentration levels of macronutrients in plant aerial part and root system, and nutritional disorders were evaluated. Omitting elements interfered in the concentration of elements in the various plant tissues and this had as consequences limited vegetative growth, reduced dry matter and led to the development of the typical deficiency symptoms of each element. Although potassium was the most demanded of all elements, nitrogen and calcium were the most growth limiting ones. [ABSTRACT FROM PUBLISHER]

The effects of a low-external-input soil fertility enhancement solution – hereafter termed 'nitrolimigation' were examined, as a preferred technique of applying nitrogen and calcium in the "Acid Sands" soils of southern Nigeria. Two types of nitrogenous fertilizer sources [urea and liquid pig manure (LPM)] and two types of lime {limestone (CaCO3) and hydrated lime [Ca(OH)2]} were used both in greenhouse and in field experiments at varying levels: Urea [CO (NH2)2] 0, 40, 50, 80, 100, 120, and 150 kg ha−1; lime 0, 0.1, 0.3, 0.5, 1.0, 5.0, and 10.0 metric tonnes per hectare (t ha−1) and LPM 0, 30, 60, 90, and 120 t ha−1. The rates were arranged factorially and laid out in randomized complete block design (RCBD). The results indicated that combining lime at 9 t ha−1 and LPM at 90 t ha−1 in irrigation water had significant (P < 0.01) positive effects on the fertility status of the "Acid Sands" soils and growth of okra- Abelmoschus esculentus, the test crop. When urea was combined with hydrated lime, it reduced acidity and provided nutrient balance in the Acid Sands of Calabar. Total nitrogen was significantly (P < 0.01) boosted from 0.05 to 0.11%, base saturation (BS) from 46 to 62%, and exchange acidity was reduced from 2.93 to 1.35 cmol kg−1. Combining urea (46-0-0) at 80 kg ha−1 with lime (CaCO3) at 5 t ha−1 raised the soil pH from 4.4 to 7.1. Exchange acidity was reduced from 0.8 cmol kg−1 to a negligible value, but electrical conductivity was improved from 170.7 to 291.9 μS cm−1. When LPM and lime were combined, organic carbon was increased from 2.75 to 2.93%, BS was increased from 46.72 to 75.19%, and pH was raised from 6.0 to 6.73. Plant height was increased from 9.5 to 16.9 cm while mean number of leaves was also increased from 5.6 to 6.3 only with lower level of lime (3 t ha−1) and LPM at 90 t ha−1. Of the nitrogen and calcium sources, LPM and limestone were better at 120 t ha−1 and 9 t ha−1, respectively, to offset soil acidity, boost nutrient availability, and provide balanced nutrition to arable crops grown on the "Acid Sands" of southern Nigeria. [ABSTRACT FROM AUTHOR]

In Brazil there are two usual forms of supplying zinc (Zn) to coffee plants, in the soil with macronutrient fertilizers or by means of foliar sprayings. Both have limitations that compromise the Zn availability to the plant. This study examined the plant responses to the foliar sprays with ZnSO4 and insertion of Zn salt tablets, made with a mix of Zn sources, into the orthotropic branches of Coffea arabica L. Zinc supplied by foliar sprays or tablets inserted into the trunk both increased leaf Zn content, although the tablets provided more consistent Zn supply. Coffee production was higher with Zn treatments, regardless of the method of supply. The supply of Zn by the insertion of tablets into coffee tree trunks thus proved to be a promising way to supply Zn. [ABSTRACT FROM AUTHOR]

An experiment was conducted to assess the zinc (Zn) availability to wheat in alkaline soils during Rabi 2009–2010. Wheat seedlings in pots having 2 kg alkaline sandy soil per pot were treated with 5, 10 and 15 kg Zn ha−1 as soil and with 0.5 and 1.0% zinc sulfate (ZnSO4) as foliar application. Results showed that Zn increasing levels in soil helped in phosphorus uptake up to boot stage but its conversion to grain portion lacked in Zn treated plants. Potassium (K) uptake also increased up to 6.24% in boot stage with treatment of 10 kg Zn ha−1 + 1.0% ZnSO4 foliar spray. Zinc (Zn) concentration increased in plant tissues with the increasing level of Zn application but this disturbed the phosphorus (P)-Zn interaction and, thus, both of the nutrients were found in lesser quantities in grains compared to the control. Despite of the apparent sufficient Zn level in soil (1.95 mg kg−1), improvement in growth and yield parameters with Zn application indicate that the soil was Zn deplete in terms of plant available Zn. The above findings suggest that the figure Zn sufficiency in alkaline soil (1.0 mg kg−1) should be revised in accordance to the nature and type of soils. Furthermore, foliar application of Zn up to 1.0% progressively increased yield but not significantly; and it was recommended that higher concentrations might be used to confirm foliar application of Zn as a successful strategy for increasing plant zinc levels. [ABSTRACT FROM AUTHOR]

Salinity, as a wide spread problem around the globe, can drastically limits the crop growth and productivity. Therefore, there is a growing need to mitigate the drastic effects of this abiotic stress through the use some sustaiable short-term or long term approaches. An investigation was carried out to assess the potential role of 24-epibrassinolide (EBL) in mitigating the drastic effects of salt stress on growth, water relations, osmolytes, and ions accumulation of salt-tolerant and salt-sensitive pea genotypes. EBL treatment significantly altered the leaf water status and accumulation of osmolytes and various ions in salt-stressed [with sodium chloride (+NaCl)] plants. The plants of both salt-tolerant and salt-sensitive genotypes, subjected to +NaCl conditions had a significant reduction in plant fresh and dry weights, internodal distance, leaf area (LA), leaf water potential (w), leaf osmotic potential (o), leaf turgor potential (t), relative water content (RWC), number of seeds pod−1, seed weight, root/leaf inorganic osmolytes (Ca2+, K+ and Mg2+), while increased the levels of root/leaf proline, glycinebetaine, total free amino acids, total soluble sugars, sodium (Na+), and chloride (Cl−). There was non-significant effect of EBL on number of pods plant−1 both under saline and non-saline conditions. However, the foliar application of EBL significantly alleviated the deleterious effects of salinity by improving the plant biomass, water relations and concentration of organic/inorganic osmolytes and yield attributes. However, EBL minimized the drastic effects of salt stress by limiting the root/leaf Na+ and Cl− contents. It can be concluded that EBL efficiently alleviated the salinity-induced drastic effects by improving the water status of plant tissues, which led to salt dilution within plant tissues, thus minimized the ion-toxicity, ultimately elevated the plant growth by minimizing the toxic action of Na+ and Cl−. Secondly, EBL augmented the salt-tolerance capacity of tested pea genotypes by enhancing their osmotic adjustment potential, in terms of high accumulation of organic and inorganic osmolytes within leaf and root tissues. [ABSTRACT FROM AUTHOR]

This study comparatively evaluates phosphorus (P) use efficiency of safflower and sunflower in view of identifying low input oil crops. Sunflower accumulated more P than safflower at all equivalent P supplies. Sunflower was more efficient at their best P supplies to utilize absorbed P than safflower in terms of efficiency ratio and utilization index. Yield response curves interpreting the functional relationship between nutrient supply and yield using Michaelis-Menten equation indicate that sunflower is less sensitive to inadequate P supply and thus more P-efficient than safflower with respect to yield, as the term ‘Km’ is lower for sunflower. The minimal P amount per pot required to trigger yield formation (term ‘Cmin’) was lower in sunflower than safflower. Harvest Index in sunflower out-yielded that of safflower at all P supplies. Critical deficiency contents of sunflower were lower than that for safflower. It can be concluded that safflower cannot be considered as low-input crop. [ABSTRACT FROM PUBLISHER]

Frost is known to directly affect flowering wheat plants (Triticum aestivum L.) and lead to reduced grain yield. Additionally, it may increase wheat susceptibility to economically important pests, such as aphids (Hemiptera: Aphididae). Wheat plants at flowering stage were exposed to one of the three temperature treatments: ambient (11-12°C), 0°C, and -3°C for 60 min. Preference (3-choice) and performance (no-choice) bioassays with aphids (Rhopalosiphum padi L.) were conducted 1, 3, 6, and 12 d after temperature treatments to assess effects of temperature-induced stress over time. As an initial feasibility study of using remote sensing technologies to detect frost-induced stress in flowering wheat plants, hyperspectral imaging data were acquired from wheat plants used in preference bioassays. Element analysis of wheat plants was included to determine the effect of temperature-induced stress on the nutritional composition of flowering wheat plants. The results from this study support the following cause--effect scenario: a 60-min exposure to low temperatures caused a significant decrease in potassium and copper content of wheat plants 6 d after temperature exposure, and it coincided with a marked increase in preference by aphids of wheat plants. The preference exhibited by aphids correlated positively with performance of aphids, so the preference--performance hypothesis was confirmed and possibly driven by potassium and copper content of wheat plants. In addition, we demonstrated that hyperspectral imaging data can be used to detect frost-induced susceptibility to aphid infestation in flowering wheat plants. These findings justify further research into airborne remote sensing of frost-induced stress and the possible secondary effects on crop susceptibility to arthropod pests. [ABSTRACT FROM AUTHOR]

Critical nutrient concentrations are required for assessing the level of crop nutrition. Our objectives were to validate an existing model of critical phosphorus concentration (Pc = 0.94 + 0.107/V) in the shoot biomass (SB) of wheat (Triticum aestivum L.) and to assess the alternative approach of expressing Pc as a function of SB rather than shoot N concentration (N). We applied four rates of P fertilizer (0,10, 20, and 30 kg P ha ) on soils with a low to medium available P concentration at four locations in three countries (Normandin [Canada; 2010, 2011, 2012], Brandon [Canada; 2010, 2012], Ylistaro [Finland; 2010, 2011], and Beijing [China; 2012]) for a total of 8 site-years. Shoot biomass, and N and P concentrations were measured on five dates with 1-wk intervals from vegetative to late heading stages of development, and grain yield was measured. Increasing P fertilization did not increase grain yield at any of the 8 site-years and had little effect on SB. Under nonlimiting P conditions achieved in most cases with no applied P, the allometric relationship between Pc and SB differed among locations, while the relationship between Pc and shoot N concentration (Pc = -0.677 + 0.221N - 0.00292N², R² = 0.82, P < 0.001) was independent of locations. This model of critical P concentration predicts lower Pc values than that previously reported, mostly for high shoot N concentrations. This predictive model of Pc can be used to quantify the degree of P deficiency during the wheat growing season. [ABSTRACT FROM AUTHOR]

To maximize recoverable sucrose from sugarbeet (Beta vulgaris L.), producers must effectively manage added N, be it from urea or organic sources such as manure or composted manure. Our study's objective was to determine the effects of a one-time application of stockpiled and composted dairy cattle (Bos taurus) manure on sugarbeet N uptake, nitrogen recovery (NR) and nitrogen use efficiency (NUE). First-year Site A treatments included a control (no N), urea (202 kg N ha-1), compost (218 and 435 kg estimated available N ha-1), and manure (140 and 280 kg available N ha-1). Site B treatments were a control, urea (82 kg N ha-1), compost (81 and 183 kg available N ha-1), and manure (173 and 340 kg available N ha-1). Compost and manure were incorporated into two silt loams, a Greenleaf (fine-silty, mixed, superactive, mesic Xeric Calciargid) near Parma, ID, in fall 2002 and 2003 and a Portneuf (coarse-silty, mixed, superactive, mesic Durinodic Xeric Haplocalcid) near Kimberly, ID, in fall 2002 with sugarbeet planted the following spring. At each site, N uptake of sugarbeet tops, but not roots, was similar whether fertilized with urea or organic N, regardless of rate. Incorporating equal organic amendment rates to 0.05 rather than 0.10 m increased whole-plant N uptake 1.13-fold, to 163.3 kg N ha-1. In general, NR varied among fertilizer sources such that urea » manure > compost. Where similar available N rates were supplied, NUE ranged from 44.1 to 83.5 kg sucrose kg-1 available N, not differing among inorganic and organic N sources within site-years. [ABSTRACT FROM AUTHOR]

Background: Citrus represents a crop of global importance both in economic impact and significance to nutrition. Citrus production worldwide is threatened by the disease Huanglongbing (HLB), caused by the phloem-limited pathogen Liberibacter spp.. As a source of stable HLB-resistance has yet to be identified, there is Candidatus considerable interest in characterization of novel disease-associated citrus genes. Results: A gene family of Small Cyclic Amphipathic Peptides (SCAmpPs) in citrus is described. The citrus genomes contain 100-150 SCAmpPs genes, approximately 50 of which are represented in the citrus EST database. These genes encode small ~50 residue precursor proteins that are post-translationally processed, releasing 5-10 residue cyclic peptides. The structures of the SCAmpPs genes are highly conserved, with the small coding domains interrupted by a single intron and relatively extended untranslated regions. Some family members are very highly transcribed in specific citrus tissues, as determined by representation in tissue-specific cDNA libraries. Comparison of the ESTs of related SCAmpPs revealed an unexpected evolutionary profile, consistent with targeted mutagenesis of the predicted cyclic peptide domain. The SCAmpPs genes are displayed in clusters on the citrus chromosomes, with apparent association with receptor leucine-rich repeat protein arrays. This study focused on three SCAmpPs family members with high constitutive expression in citrus phloem. Unexpectedly high sequence conservation was observed in the promoter region of two phloem-expressed SCAmpPs that encode very distinct predicted cyclic products. The processed cyclic product of one of these phloem SCAmpPs was characterized by LC-MS-MS analysis of phloem tissue, revealing properties consistent with a K+ ionophore. Conclusions: The SCAmpPs amino acid composition, protein structure, expression patterns, evolutionary profile and chromosomal distribution are consistent with designation as ribosomally synthesized defense-related peptides. [ABSTRACT FROM AUTHOR]