Effect of nitrogen and potassium fertilizer on growth,yield and chemical composition of sweet fennel

Abstract

In this study, the effect of different levels of nitrogen (N) and potassium (K) fertilizers on vegetative fresh bulb yield, quality and biochemical attributes of sweet fennel were investigated in spring 2017 and 2018. Treatments consisted of 0, 50, 100, or 150?kg ha^?1 of N and K in a randomized complete block design with three replications. Results showed that, the bulb fresh yield increased with application of N and K in both years, while the higher level of K had significant adverse effect in first year. Results also showed that sweet fennel bulb treated by N and K exhibited higher vitamin C, total phenols and flavonoid contents, and antioxidant capacity, especially in first year. In both years, alone or combined application of N and K increased total soluble solids (TSS) content as compared to control, and this effect was more pronounced in 2017 season. Macronutrient contents of bulb including magnesium (Mg), phosphorus (P), K, N, and calcium (Ca) were significantly enhanced by NK fertilizer, however an alone application of K decreased Ca and Mg nutrient contents. Therefore, to improve fresh bulb yield, quality and antioxidant capacity in sweet fennel, 150?kg ha^?1 K and 100?kg ha^?1 N is recommended.     

Selenium in lemon balm plants: Productivity,phytotoxicity and drought alleviation

Since studies on the effects of selenium (Se) supplementation in water-stressed plants have mainly focused on cereal crops, the specific reports regarding Se-mediated adaptation to drought stress in medicinal vegetables are scant. Thus, we investigated the responses of Melissa officinalis to Se supplementation. Selenium contents were increased in leaves and grains by supplemental Se. Selenium foliar application at 1 mg l^?1 could be useful to increase the vegetative and reproductive growth of Se-enriched plants under well-watered conditions but at 20 mg l^?1 led to toxicity and caused damage to shoots. Drought stress significantly inhibited plant growth by chlorophyll degradation and reduced net carbon dioxide (CO₂) assimilation rate. Although Se at 1 mg l^?1 could increase biomass production under well-watered conditions in addition to the stimulation of antioxidant system under water stress, it could not ameliorate the negative effect of drought on productivity.     

Enantiomeric discrimination and quantification of the chiral organophosphorus pesticide fenamiphos in aqueous samples by a novel and selective ³¹P nuclear magnetic resonance spectroscopic method using cyclodextrins as chiral selector

A rapid, selective, and accurate quantitative 31P nuclear magnetic resonance (31P NMR) spectroscopy method was used for the chiral recognition of the racemic organophosphorus pesticide fenamiphos using chiral solvating agents (CSAs). Six neutral cyclodextrins (CDs) (α-CD, β-CD, methyl-β-CD, hydroxyethyl-β-CD, hydroxypropyl-β-CD, and hydroxypropyl-γ-CD) and two anionic CDs (carboxymethyl-β-CD and carboxyethyl-β-CD) were selected for these experiments. The shift displacement values (Δδ), after addition of each of the eight CDs in the highest possible molar ratio to a guest, were recorded. The results showed that β-CD and hydroxypropyl-β-CD were the best chiral solvating agents for the enantiomeric discrimination of fenamiphos. Two-dimension rotating frame nuclear Overhauser spectroscopy (ROESY) was used to investigate the structure of the β-CD-fenamiphos inclusion complex in aqueous solution. To determine the fenamiphos enantiomers, a calibration curve was drawn for two enantiomers over the range of 0.05-0.25 mg mL?1. The limits of detection (S/N = 3) were obtained as 0.0068 and 0.0060 mg mL?1 for fenamiphos enantiomers. The recovery studies were performed on aqueous real samples ranging from 94 to 107% with coefficients of variation of ≤ 9%.     

Cadmium accumulation and partitioning in Ocimum basilicum as influenced by the application of various potassium fertilizers

Potassium (K) is one of the major essential nutrient elements whose application of organic or nano-chelate-fertilizers has received increased attention recently. Cadmium (Cd) contamination in agricultural soils and environment is increasing due to the over-application of Cd-containing phosphate fertilizers. But few studies have been carried out on the environmental influences of K-nano-chelate fertilizers especially on Cd-polluted soils. Therefore, the effects of K-fertilizer application in different rates (0, 100 and 200 mg kg^?1 soil) and forms (KCl, K₂SO₄ and K-nano-chelate) on Cd content and partitioning in Ocimum basilicum grown on an artificially Cd-contaminated calcareous soil (with 40 mg Cd kg^?1 soil) were studied under greenhouse conditions. Cadmium decreased shoot dry weight (SDW), but did not affect root dry weight (RDW) and no consistent trend was observed with applied K. Cadmium increased shoot and root Cd concentration or uptake. KCl and K₂SO₄ increased shoot Cd concentration compared to that of control, whereas K-nano-chelate did not affect it. In Cd-treated soils the mean value of Cd translocation factor (ratio of Cd concentration in shoots to that of roots) decreased by 60% as compared to that of the control. Application of 100 mg K-K₂SO₄ and 100 and 200 mg K-nano-chelate increased the Cd translocation factor by 49, 59 and 112% in Cd-treated soils, respectively. In Cd-treated soils, greater amounts of Cd accumulated in roots. K-nano-chelate could mitigate the adverse effect of Cd on SDW and Cd accumulation in plants grown on Cd-polluted soils, so the risk of Cd entrance to the food chain is reduced (however, in Cd-untreated soils, K-nano-chelate increased the Cd translocation factor higher than other K sources). In Cd-polluted soils KCl was the most inappropriate fertilizer that may intensify Cd accumulation in plants. However, it may be useful in the phytoremediation of Cd-polluted soils.     

The effect of different biochars on the growth and water use efficiency of fenugreek (Trigonella foenum-graecum L.)

In two identical pot trials, we investigated the effect of different biochars on the growth and water use efficiency (WUE) of fenugreek (Trigonella foenum-graecum L.) grown with and without water stress. Plants were grown in pots with and without biochar. Rice husk (RH), standard rice husk (SRH), standard wheat straw (SWS) or standard oilseed rape straw (SOS) biochars were added at a rate of 2% by weight. Irrigation was reduced from 80% of field capacity to 40% in half of the pots to create water stress when 50% of the plants flowered. No significant interaction was observed between irrigation and biochar treatments. Water stress resulted in smaller plants (11.5%), fewer pods (16.1%) and reduced 100-seed weight (12.6%), seed yield (20.1%) and plant dry weight (55.0%). All standard biochars increased plant dry weight in a range of 18%−25% compared with the controls. There was no significant effect of biochar on the number of pods and seed weight. Only RH, SWS and SOS biochar increased the number of seeds pod⁻¹ by 9.0%−14.5% compared with the controls regardless of water stress. RH and SOS biochars increased seed yield by 16.7 and 21.6%, respectively. RH, SWS and SOS biochar increased the WUE by 17.3%, 10.1% and 16.2% regardless of water stress, respectively. Based on the experiment, we recommend farmers to add biochar whatever type they have available. However, RH and SOS seem to be better than the others are, as they seem to be able to increase seed yield and WUE considerably.     

Bacterial DNA Detection in the Blood of Healthy Subjects

Background:The presence of microbiome in the blood samples of healthy individuals has been addressed. However, no information can be found on the healthy human blood microbiome of Iranian subjects. The current study is thus aimed to investigate the existence of bacteria or bacterial DNA in healthy individuals. Methods: Blood samples of healthy subjects were incubated in BHI broth at 37 °C for 72 h. The 16S rRNA PCR and sequencing were performed to analyze bacterial isolates. The 16S rRNA PCR was directly carried out on DNA samples extracted from the blood of healthy individuals. NGS was conducted on blood samples with culture-positive results.Results:Fifty blood samples were tested, and six samples were positive by culture as confirmed by Gram staining and microscopy. The obtained 16S rRNA sequences of cultured bacterial isolates revealed the presence of Bacilli and Staphylococcus species by clustering in the GeneBank database (≥97% identity). The 16S rRNA gene sequencing results of one non-cultured blood specimen showed the presence of Burkholderia. NGS results illustrated the presence of Romboutsia, Lactobacillus, Streptococcus, Bacteroides, and Staphylococcus in the blood samples of positive cultures.Conclusion: The dormant blood microbiome of healthy individuals may give the idea that the steady transfer of bacteria into the blood does not necessarily lead to sepsis. However, the origins and identities of blood-associated bacterial rDNA sequences need more evaluation in the healthy population.Key Words: Bacteria, Blood, Microbiome, Sequencing, 16S rRNA     

Genetic diversity and population structure of four Iranian alfalfa populations revealed by sequence-related amplified polymorphism (SRAP) markers

In the present study, genetic diversity of 48 individual plants from four Iranian cultivated populations of alfalfa (Medicago sativa L.) was evaluated using sequence-related amplified polymorphism (SRAP) markers. Fourteen SRAP primer combinations produced 193 fragments of which 95 were polymorphic. The number of polymorphic fragments detected per primer combination ranged from 3 to 10 bands with an average of 6.78 bands. Average polymorphic information content (PIC) was 0.343 for all primer combinations. Although the AMOVA (analysis of molecular variance) results showed a significant difference in the genetic diversity among the populations (P < 0.0001), the genetic variation mainly caused by the variation of intra population accounted for 93.17% of the total genetic variation. Unweighted pair-group method arithmetic average (UPGMA) analysis of the marker data clearly separated the populations of subtropical (Yazdi) and semi-cold (Hamadani and Nikshahri) as well as Kodi, an improved population. It can be concluded that SRAP markers are useful for studying diversity and relationships among and within alfalfa populations.     

Changes in essential oil accumulation of Moldavian balm (Dracocephalum moldavica L.) in response to phosphate biological and chemical fertilizer

A field experiment was carried out with a split plot arrangement based on a randomized complete block design with three replications in 2014. Triple super phosphate (0, 3.75, 7.5, 11.25 and 15 g m^?2) was applied in main plots and phosphate bio-fertilizer (seed inoculation and topdressing) was allocated to sub plots. Results indicated that application of plants with phosphorus (P) bio-fertilizer as topdressing increased plant height and the number of the lateral branches under low levels of chemical P fertilizer, while plants from seed inoculated with P bio-fertilizer had more of those traits under high levels of chemical P fertilizer. Maximum leaf and flower dry weights were found under the lowest level of chemical P fertilizer. Moldavian balm plant demonstrated highly responsiveness to biological fertilizers in terms of increase in essential oil (EO) percentage and yield. It can be concluded that the effects of bio-fertilizer as seed inoculation is more during the early vegetative growth of plants. Thus, plants from seeds inoculated with P bio-fertilizer treatment had more biomass and EO percentage under high levels of chemical P fertilizer.     

A methodology for up-scaling irrigation losses

This paper presents a methodology for up-scaling field irrigation losses and quantifying relative losses at the irrigation area level for potential water savings. Two levels of analysis were considered: First, the field level where irrigation is applied. Second, the irrigation area level, where the field level losses are aggregated, or up-scaled, using average loss functions. In this up-scaling approach, detailed crop-soil-water modelling can capture the variability of physical parameters (such as soils, crops, water table depth, and management practices) at the field level which are then used to derive loss functions for aggregating losses at higher scales (irrigation area level). This allows potential field-level adaptations and water management changes made by individual farmers to be assessed for impact at the larger irrigation area level. The APSIM farming systems model was used for simulation of crops (wheat, rice, and soybean) and their interaction with the wider system processes at the field level. Given the climate, soil, and management information (sowing, fertilisation, irrigation, and residue management), the model simulates infiltration, the soil moisture profile, plant water uptake, soil evaporation, and deep drainage on a daily basis. Then, by placing the field level analysis in the context of the wider irrigation system or catchment, it is possible to correlate field level interventions (e.g. water savings measures) with water requirements at these higher levels. Application of this method in the Coleambally Irrigation Area in NSW, Australia, demonstrated that an exponential function can describe the relationship between deep drainage losses and the water table depth for different soil, crop, and water table depth combinations. The rate of loss increase (slope of the curve) with the water table depth is higher on lighter (higher intake rates) soils than on heavy soils and is more pronounced in areas under rice cultivation. We also demonstrate that this analysis technique can assist in identifying spatial distribution of losses in irrigation areas, considering water table depth as an additional factor, leading to targeted areas for water-saving measures.     

NEW MOLYBDENUM-HYPERACCUMULATOR AMONG PLANT SPECIES GROWING ON MOLYBDENUM MINE- A BIOCHEMICAL STUDY ON TOLERANCE MECHANISM AGAINST METAL TOXICITY

The aim of this work was to determine metal accumulation by plants growing on three molybdenum-mine zones and their tolerance strategies. The plants from tailing, extracting and non-contaminated zones were sampled with their corresponding soils. The results show that molybdenum (Mo) and copper (Cu) were at toxic levels in soils and their levels varied in 44 collected species from 21 families. Ajuga chamaecistus and Cramb orientalis L. excluded Mo and Cu, respectively. Achilla tenuifollia as Mo-hyperaccumulator with total Mo (1979 mg kg^?1) and then Erodium ciconium with 1308 mg kg^?1 Mo and Conyza Canadensis with 618 mg kg^?1 Cu were moderate metal accumulators. They stored considerable levels of metals in their leaves vacuoles and elevated the levels of phytochelatins, cysteine and glutathione and induced antioxidant enzymes. In conclusion, this study indicated that some collected plants excluded metals. In metal-accumulators, antioxidant enzymes, phytochelatins and sequestration of excess metals were involved in their tolerance mechanism.