Effect of silicon nanoparticle-based biochar on wheat growth, antioxidants and nutrients concentration under salinity stress.

Globally, salinity is an important abiotic stress in agriculture. It induced oxidative stress and nutritional imbalance in plants, resulting in poor crop productivity. Applying silicon (Si) can improve the uptake of macronutrients. On the other hand, using biochar as a soil amendment can also decrease salinity stress due to its high porosity, cation exchange capacity, and water-holding capacity. That's why the current experiment was conducted with novelty to explore the impact of silicon nanoparticle-based biochar (Si-BC) on wheat cultivated on salt-affected soil. There were 3 levels of Si-BC, i.e., control (0), 1% Si-BC1, and 2.5% Si-BC2 applied in 3 replicates under 0 and 200 mM NaCl following a completely randomized design. Results showed that treatment 2.5% Si-BC2 performed significantly better for the enhancement in shoot and root length, shoot and root fresh weight, shoot and root dry weight, number of leaves, number of tillers, number of spikelets, spike length, spike fresh and dry weight compared to control under no stress and salinity stress (200 mM NaCl). A significant enhancement in chlorophyll a (~ 18%), chlorophyll b (~ 22%), total chlorophyll (~ 20%), carotenoid (~ 60%), relative water contents (~ 58%) also signified the effectiveness of treatment 2.5% Si-BC2 than control under 200 mM NaCl. In conclusion, treatment 2.5% Si-BC2 can potentially mitigate the salinity stress in wheat by regulating antioxidants and improving N, K concentration, and gas exchange attributes while decreasing Na and Cl concentration and electrolyte leakage. More investigations at the field level are recommended for the declaration of treatment 2.5% Si-BC2 as the best amendment for alleviating salinity stress in different crops under variable climatic conditions.

Differential responses of chili varieties grown under cadmium stress.

Heavy metal cadmium (Cd) naturally occurs in soil and is a hazardous trace contaminant for humans, animals, and plants. The main sources of Cd pollution in soil include overuse of phosphatic fertilizers, manure, sewage sludge, and aerial deposition. That's why an experiment was conducted to analyze the effect of Cd toxicity in Capsicum annuum L. by selecting its seven varieties: Hybrid, Desi, Sathra, G-916, BR-763, BG-912, and F1-9226. Cadmium was spiked in soil with four levels, i.e., (0, 3, 4, and 5 mg Cd kg- 1 of soil) for a week for homogeneous dispersion of heavy metal. Chili seeds were sown in compost-filled loamy soil, and 25-day-old seedlings were transplanted into Cd-spiked soil. Cadmium increasing concentration in soil decreased chili growth characteristics, total soluble sugars, total proteins, and amino acids. On the other hand, the activities of antioxidant enzymes were increased with the increasing concentration of Cd in almost all the varieties. Treatment 5 mg Cd/kg application caused - 197.39%, -138.78%, -60.77%, -17.84%, -16.34%, -11.82% and - 10.37% decrease of carotenoids level in chili V2 (Desi) followed by V4 (G-916), V1 (Hy7brid), V7 (F1-9226), V6 (BG-912), V5 (BR-763) and V3 (Sathra) as compared to their controls. The maximum flavonoids among varieties were in V5 (BR-763), followed by V6 (BG-912), V7 (F1-9226), V3 (Sathra) and V1 (Hybrid). Flavonoids content was decreased with - 37.63% (Sathra), -34.78% (Hybrid), -33.85% (G-916), -31.96% (F1-9226), -31.44% (Desi), -30.58% (BR-763), -22.88% (BG-912) as compared to their control at 5 mg Cd/kg soil stress. The maximum decrease in POD, SOD, and CAT was - 31.81%, -25.98%, -16.39% in chili variety V7 (F1-9226) at 5 mg Cd/kg stress compared to its control. At the same time, maximum APX content decrease was - 82.91%, followed by -80.16%, -65.19%, -40.31%, -30.14%, -10.34% and - 6.45% in V4 (G-916), V2 (Desi), V3 (Sathra), V6 (BG-912), V1 (Hybrid), V7 (F1-9226) and V5 (BR-763) at 5 mg Cd/kg treatment as compared to control chili plants. The highest CAT was found in 5 chili varieties except Desi and G-916. Desi and G-916 varieties. V5 (BR-763) and V6 (BG-912) were susceptible, while V1 (Hybrid), V3 (Sathra), and V7 (F1-9226) were with intermediate growth attributes against Cd stress. Our results suggest that Desi and G-916 chili varieties are Cd tolerant and can be grown on a large scale to mitigate Cd stress naturally.

Modulation of sunflower growth via regulation of antioxidants, oil content and gas exchange by arbuscular mycorrhizal fungi and quantum dot biochar under chromium stress.

Chromium (Cr) toxicity significantly threatens sunflower growth and productivity by interfering with enzymatic activity and generating reactive oxygen species (ROS). Zinc quantum dot biochar (ZQDB) and arbuscular mycorrhizal fungi (AMF) have become popular to resolve this issue. AMF can facilitate root growth, while biochar tends to minimize Cr mobility in soil. The current study aimed to explore AMF and ZQDB combined effects on sunflower plants in response to Cr toxicity. Four treatments were applied, i.e. NoAMF + NoZQDB, AMF + 0.40%ZQDB, AMF + 0.80%ZQDB, and AMF + 1.20%ZQDB, under different stress levels of Cr, i.e. no Cr (control), 150 and 200 mg Cr/kg soil. Results showed that AMF + 1.20%ZQDB was the treatment that caused the greatest improvement in plant height, stem diameter, head diameter, number of leaves per plant, achenes per head, 1000 achenes weight, achene yield, biological yield, transpiration rate, stomatal conductance, chlorophyll content and oleic acid, relative to the condition NoAMF + No ZQDB at 200 mg Cr/kg soil. A significant decline in peroxidase (POD), superoxide dismutase (SOD), and catalase (CAT) while improvement in ascorbate peroxidase (APx), oil content, and protein content further supported the effectiveness of AMF + 1.20%ZQDB against Cr toxicity. Our results suggest that the treatment AMF + 1.20%ZQDB can efficiently alleviate Cr stress in sunflowers.

Genomic exploration of Sesuvium sesuvioides: comparative study and phylogenetic analysis within the order Caryophyllales from Cholistan desert, Pakistan.

BACKGROUND: The Aizoaceae family's Sesuvium sesuvioides (Fenzl) Verdc is a medicinal species of the Cholistan desert, Pakistan. The purpose of this study was to determine the genomic features and phylogenetic position of the Sesuvium genus in the Aizoaceae family. We used the Illumina HiSeq2500 and paired-end sequencing to publish the complete chloroplast sequence of S. sesuvioides. RESULTS: The 155,849 bp length cp genome sequence of S. sesuvioides has a 36.8% GC content. The Leucine codon has the greatest codon use (10.6%), 81 simple sequence repetitions of 19 kinds, and 79 oligonucleotide repeats. We investigated the phylogeny of the order Caryophyllales' 27 species from 23 families and 25 distinct genera. The maximum likelihood tree indicated Sesuvium as a monophyletic genus, and sister to Tetragonia. A comparison of S. sesuvioides, with Sesuvium portulacastrum, Mesembryanthemum crystallinum, Mesembryanthemum cordifolium, and Tetragonia tetragonoides was performed using the NCBI platform. In the comparative investigation of genomes, all five genera revealed comparable cp genome structure, gene number and composition. All five species lacked the rps15 gene and the rpl2 intron. In most comparisons with S. sesuvioides, transition substitutions (Ts) were more frequent than transversion substitutions (Tv), producing Ts/Tv ratios larger than one, and the Ka/Ks ratio was lower than one. We determined ten highly polymorphic regions, comprising rpl22, rpl32-trnL-UAG, trnD-GUC-trnY-GUA, trnE-UUC-trnT-GGU, trnK-UUU-rps16, trnM-CAU-atpE, trnH-GUG-psbA, psaJ-rpl33, rps4-trnT-UGU, and trnF-GAA-ndhJ. CONCLUSION: The whole S. sesuvioides chloroplast will be examined as a resource for in-depth taxonomic research of the genus when more Sesuvium and Aizoaceae species are sequenced in the future. The chloroplast genomes of the Aizoaceae family are well preserved, with little alterations, indicating the family's monophyletic origin. This study's highly polymorphic regions could be utilized to build realistic and low-cost molecular markers for resolving taxonomic discrepancies, new species identification, and finding evolutionary links among Aizoaceae species. To properly comprehend the evolution of the Aizoaceae family, further species need to be sequenced.

Uncovering the impact of AM fungi on wheat nutrient uptake, ion homeostasis, oxidative stress, and antioxidant defense under salinity stress.

The growth of wheat (Triticum aestivum) is constrained by soil salinity, although some fungal species have been shown to enhance production in saline environments. The yield of grain crops is affected by salt stress, and this study aimed to investigate how arbuscular mycorrhizal fungus (AMF) mitigates salt stress. An experiment was conducted to assess the impact of AMF on wheat growth and yield in conditions of 200 mM salt stress. Wheat seeds were coated with AMF at a rate of 0.1 g (108 spores) during sowing. The results of the experiment demonstrated that AMF inoculation led to a significant improvement in the growth attributes of wheat, including root and shoot length, fresh and dry weight of root and shoot. Furthermore, a significant increase in chlorophyll a, b, total, and carotenoids was observed in the S2 AMF treatment, validating the effectiveness of AMF in enhancing wheat growth under salt stress conditions. Additionally, AMF application reduced the negative effects of salinity stress by increasing the uptake of micronutrients such as Zn, Fe, Cu, and Mn while regulating the uptake of Na (decrease) and K (increase) under salinity stress. In conclusion, this study confirms that AMF is a successful strategy for reducing the negative effects of salt stress on wheat growth and yield. However, further investigations are recommended at the field level under different cereal crops to establish AMF as a more effective amendment for the alleviation of salinity stress in wheat.

Effect of nanobiochar (nBC) on morpho-physio-biochemical responses of black cumin (Nigella sativa L.) in Cr-spiked soil.

Chromium is a highly toxic heavy metal. High concentrations of Cr (III) can affect metabolic processes in plants, resulting in different morphological, physiological, and biochemical defects. Agricultural practices such as sewage irrigation, over-fertilization, and sewage sludge application contribute significantly to Cr contamination. It can reduce the growth of plants by affecting the activity of antioxidant enzymes. The materials in nano form play an important role in nano-remediation and heavy metals absorption due to their high surface area and micropores. This research was conducted to study the potential of foliar application of nanobiochar/nBC (100 mg/L-1 and 150 mg/L-1) for mitigation of Cr (III) stress (200 mg/kg and 300 mg/kg) in black cumin (Nigella sativa) plants. The results showed that increased Cr stress (300 mg/kg) decreased the plant growth parameters, chlorophyll content, total soluble sugars, and proteins. However, increased the level of hydrogen peroxide (H2O2) and malondialdehyde acetate (MDA) as a result of the activity of antioxidant enzymes (Catalase, Superoxide dismutase, peroxidase dismutase, and ascorbic peroxidase) increased in Nigella sativa seedlings. Foliar application of the nBC (100 mg/L-1) increased plant growth parameters, chlorophyll content, and osmoprotectants, while decreasing the levels of oxidative stress markers (H2O2 and MDA). Furthermore, with the application of nBC, the antioxidant enzyme activity considerably improved. Improved antioxidant activity shows that nBC helped to decrease oxidative stress, which in return improved the growth of Nigella sativa seedlings. Overall, present study findings concluded that foliar application of nBC in Nigella sativa seedlings improved growth, chlorophyll, and antioxidant enzymes. The nBC treatment of 100 mg/L-1 showed better results compared to 150 mg/L-1 under chromium stress.

Triticum aestivum: antioxidant gene profiling and morpho-physiological studies under salt stress.

BACKGROUND: Soil salinity drastically reduced wheat growth and production in Pakistan. It is a need of an hour to identify the best suitable salt tolerance or resistant wheat varieties which shows good growth under salinity affected areas. In presented study, two wheat varieties Johar (salt tolerant) and Sarsabaz (salt sensitive) were examined under NaCl stress conditions. METHODS: Antioxidant enzyme activities were investigated in 10-days old wheat seedlings under 200 mM NaCl stress in hydroponic conditions. To investigate the various growth parameters, antioxidant enzyme activities such as superoxide dismutase (SOD: EC 1.15.1.1), catalase (CAT: EC 1.11.1.6) and ascorbate peroxidase (APX: EC 1.11.1.11) were monitored and studied. Besides this various growth parameters such as length of the roots, shoots, as well as Physiological parameters likes lipid peroxidation by malondialdehyde (MDA), hydrogen peroxide (H2O2), and proline contents and antioxidant enzyme activities were estimated. The effect of salinity was also observed on gene transcription level and eventually expression level. RESULTS: Shoot and root length were decreased in Sarsabaz variety while it showed opposite trend in johar at 200 mM salt concentration. The concentration of proline showed a noticeable rise in salt dependency. Higher concentrations of Proline in Johar were observed as compared to Sarsabaz. SOD showed the increase in activity for antioxidant enzymes. Significant increase of SOD levels were observed in shoot tissues as compared to root tissues. The results indicated that the shoots were more susceptible to salt stress. Activity of APX showed similar affects in both varieties. The production of CAT enzyme in the shoot and root tissues of both varieties showed substantial growth under increased salt stress. Furthermore, NaCl stress has increased the expression of certain genes coding for antioxidant enzymes such as catalase, superoxide dismutase, and peroxidase. Maximum expression of all the antioxidant enzyme coding genes were observed in Johar (tolerant) at 48 h exposure to salt. In contrast the expression of the all mentioned genes in Sarsabaz variety were found maximum at early hours (24 h) and gradually decreased at 48 h. CONCLUSION: The study showed that the selected salt tolerant wheat variety Johar is significantly resistant to 200 mM NaCl salt level as compared to Sarsabaz.

Synthesis of phytostabilized zinc oxide nanoparticles and their effects on physiological and anti-oxidative responses of Zea mays (L.) under chromium stress.

Chromium (Cr) is a hazardous metal that has a significant risk of transfer from soil to edible parts of food crops, including shoot tissues. Reduction of Cr accumulation is required to lower the risk of Cr-exposed in humans and animals feeding on metal-contaminated parts of such plant. Zea mays is a global staple crop irrigated intensively with Cr-contaminated water. Consequently, the objective of this study was to investigate that FI-stabilized ZnO NPs could be used as an eco-friendly and efficient amendment to reduced Cr uptake and toxicity in Zea mays. To investigate the growth parameters, physiological, oxidative stress and biochemical parameters under different Cr-VI concentrations (10.0, 15.0, and 20.0 ppm). Cr exposed Z. mays plants exhibited substantially reduced plant biomass, chlorophyll contents, and altered antioxidant enzyme activity compared to untreated control. The results revealed that foliar application of Fagonia-ZnO-NPs helps eliminate the harmful effects of Cr (VI), which can enter plants through soil pollution. Increased levels of proline, soluble sugars and various antioxidant enzymes reflected this. Mean comparisons showed that Cr stress led to a 33-50% reduction in fresh shoot weight, 73-170% in fresh root weight, 16-34% shoot length, 9.5-129% root length, Chlorophyll contents 20-33% (Chl a), 18-27% (Chl b) and 17-27% (car), 14-33% total soluble sugars, 54-170% proline content, 7-7.5% POD, 0.66-75% CAT and 32-77% APX enzyme activities compared to untreated plants. Application of FI-stabilized ZnO NPs led to an increase 21-77% in fresh shoot weight, 22-45%, fresh root weight, 3-35% shoot length, 24-154% root length, Chlorophyll contents 39-60% (Chl a), 15-79% (Chl b) and 28-82% (car), 19-52% total soluble sugars, 21-55% proline content, 14-43% POD, 34-95% CAT and 130-186% APX enzyme activities under 10, 15 and 20 ppm Cr stress respectively, compared to Cr-treated plants. However, the principal component analysis revealed that chlorophyll contents, carotenoid, CAT, APX and length were in the same group and showed a positive correlation. These data collectively suggest that phytostabilized zinc oxide NPs may be an eco-friendly solution to mitigate Cr toxicity in agricultural soils and crop plants.

The chloroplast genome of Farsetia hamiltonii Royle, phylogenetic analysis, and comparative study with other members of Clade C of Brassicaceae.

BACKGROUND: Farsetia hamiltonii Royle is a medicinally important annual plant from the Cholistan desert that belongs to the tribe Anastaticeae and clade C of the Brassicaceae family. We provide the entire chloroplast sequence of F.hamiltonii, obtained using the Illumina HiSeq2500 and paired-end sequencing. We compared F. hamiltonii to nine other clade C species, including Farsetia occidentalis, Lobularia libyca, Notoceras bicorne, Parolinia ornata, Morettia canescens, Cochlearia borzaeana, Megacarpaea polyandra, Biscutella laevigata, and Iberis amara. We conducted phylogenetic research on the 22 Brassicaceae species, which included members from 17 tribes and six clades. RESULTS: The chloroplast genome sequence of F.hamiltonii of 154,802 bp sizes with 36.30% GC content and have a typical structure comprised of a Large Single Copy (LSC) of 83,906 bp, a Small Single Copy (SSC) of 17,988 bp, and two copies of Inverted Repeats (IRs) of 26,454 bp. The genomes of F. hamiltonii and F. occidentalis show shared amino acid frequencies and codon use, RNA editing sites, simple sequence repeats, and oligonucleotide repeats. The maximum likelihood tree revealed Farsetia as a monophyletic genus, closely linked to Morettia, with a bootstrap score of 100. The rate of transversion substitutions (Tv) was higher than the rate of transition substitutions (Ts), resulting in Ts/Tv less than one in all comparisons with F. hamiltonii, indicating that the species are closely related. The rate of synonymous substitutions (Ks) was greater than non-synonymous substitutions (Ka) in all comparisons with F. hamiltonii, with a Ka/Ks ratio smaller than one, indicating that genes underwent purifying selection. Low nucleotide diversity values range from 0.00085 to 0.08516, and IR regions comprise comparable genes on junctions with minimal change, supporting the conserved status of the selected chloroplast genomes of the clade C of the Brassicaceae family. We identified ten polymorphic regions, including rps8-rpl14, rps15-ycf1, ndhG-ndhI, psbK-psbI, ccsA-ndhD, rpl36-rps8, petA-psbJ, ndhF-rpl32, psaJ-rpl3, and ycf1 that might be exploited to construct genuine and inexpensive to solve taxonomic discrepancy and understand phylogenetic relationship amongst Brassicaceae species. CONCLUSION: The entire chloroplast sequencing of F. hamiltonii sheds light on the divergence of genic chloroplast sequences among members of the clade C. When other Farsetia species are sequenced in the future, the full F. hamiltonii chloroplast will be used as a source for comprehensive taxonomical investigations of the genus. The comparison of F. hamiltonii and other clade C species adds new information to the phylogenetic data and evolutionary processes of the clade. The results of this study will also provide further molecular uses of clade C chloroplasts for possible plant genetic modifications and will help recognise more Brassicaceae family species.

Synergistic Effect of Zinc Oxide Nanoparticles and Moringa oleifera Leaf Extract Alleviates Cadmium Toxicity in Linum usitatissimum: Antioxidants and Physiochemical Studies.

Among heavy metals, cadmium (Cd) is one of the toxic metals, which significantly reduce the growth of plants even at a low concentration. Cd interacts with various plant mechanisms at the physiological and antioxidant levels, resulting in decreased plant growth. This research was conducted to exploit the potential of synergistic application of zinc oxide nanoparticles (ZnO NPs) and Moringa oleifera leaf extract in mitigation of Cd stress in linseed (Linum usitatissimum L.) plants. The main aim of this study was to exploit the role of M. oleifera leaf extract and ZnO NPs on Cd-exposed linseed plants. Cd concentrations in the root and shoot of linseed plants decreased after administration of MZnO NPs. Growth parameters of plants, antioxidant system, and physiochemical parameters decreased as the external Cd level increased. The administration of MZnO NPs to the Cd-stressed linseed plant resulted in a significant increase in growth and antioxidant enzymes. Furthermore, the antioxidative enzymes superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and ascorbate peroxidase (APX) exhibited a considerable increase in the activity when MZnO NPs were applied to Cd-stressed seedlings. The introduction of MZnO NPs lowered the levels of malondialdehyde (MDA) and hydrogen peroxide (H2O2) in the linseed plant grown in Cd-toxic conditions. The NPs decreased electrolyte leakage (EL) in Cd-stressed linseed leaves and roots. It was concluded that synergistic application of ZnO NPs and M. oleifera leaf extract alleviated Cd stress in linseed plants through enhanced activity of antioxidant enzymes. It is proposed that role of MZnO NPs may be evaluated for mitigation of numerous abiotic stresses.

Iron oxide nanoparticles and selenium supplementation improve growth and photosynthesis by modulating antioxidant system and gene expression of chlorophyll synthase (CHLG) and protochlorophyllide oxidoreductase (POR) in arsenic-stressed Cucumis melo.

Current research reveals the positive role of iron oxide nanoparticles (IONPs) and selenium (Se) in extenuation of arsenic (As) induced toxicity in Cucumis melo. C. melo plants grown in As spiked soil (20 mg kg-1 As) showed reduced growth, chlorophyll (Chl) content, photosynthetic rate, stomatal conductivity and transpiration. On the other hand, the alone applications of IONPs or Se improved growth and physiochemical parameters of C. melo plants. Additionally, exogenous application IONPs and Se synergistically improved the activity of antioxidative enzymes and glyoxalase system in C. melo plants. In addition, the collective treatment of IONPs and Se reduced As uptake, enhanced rate of photosynthesis and increased gas exchange attributes of C. melo plants under As stress. Interactive effect of IONPs and Se regulated reduced glutathione (GSH), oxidized glutathione (GSSG) and ascorbate (AsA) content in C. melo plants exposed to As-contaminated Soil. IONPs and Se treatment also regulated expression of respiratory burst oxidase homologue D (RBOHD) gene, chlorophyll synthase (CHLG) and protochlorophyllide oxidoreductase (POR). Therefore, the combined treatment of IONPs and Se may enhance the growth of crop plants by alleviating As stress.

Mitigation of bacterial spot disease induced biotic stress in Capsicum annuum L. cultivars via antioxidant enzymes and isoforms.

Bacterial spot, caused by a group of Xanthomonads (Xanthomonas spp.), is a devastating disease. It can adversely affect the Capsicum annum productivity. Scientists are working on the role of antioxidants to meet this challenge. However, research is lacking on the role of antioxidant enzymes and their isoforms in the non-compatible pathogen and host plant interaction and resistance mechanisms in capsicum varieties. The present study was conducted to ascertain the defensive role of antioxidant enzymes and their isoforms in chilli varieties Hybrid, Desi, Serrano, Padron, and Shehzadi against bacterial spot disease-induced Xanthomonas sp. The seedlings were inoculated with bacterial pathogen @ 107 CFU/mL, and samples were harvested after regular intervals of 24 h for 4 days followed by inoculation. Total plant proteins were extracted in phosphate buffer and quantified through Bradford assay. The crude protein extracts were analyzed through quantitative enzymatic assays in order to document activity levels of various antioxidant enzymes, including peroxidase (POD), Catalase (CAT), Ascorbate peroxidase (APX), and Superoxide dismutase (SOD). Moreover, the profiles appearance of these enzymes and their isoforms were determined using native polyacrylamide gel electrophoresis (PAGE) analysis. These enzymes exhibited maximum activity in Hybrid (HiR) cultivar followed by Desi (R), Serrano (S), Padron, and Shehzadi (HS). Both the number of isoforms and expression levels were higher in highly resistant cultivars compared to susceptible and highly susceptible cultivars. The induction of POD, CAT, and SOD occurs at the early stages of growth in resistant Capsicum cultivars. At the same time, APX seems to make the second line of antioxidant defense mechanisms. We found that modulating antioxidant enzymes and isoforms activity at the seedling stage was an important mechanism for mitigating plant growth inhibition in the resistant ones.

Phosphorus Nutrient Management through Synchronization of Application Methods and Rates in Wheat and Maize Crops.

Management of inorganic fertilizer is very important to obtain maximum crop yield and improved nutrient use efficiency in cereal crops. Fixation of phosphatic fertilizers in alkaline soils due to calcareousness is one of the major hurdles. It induces phosphorus nutritional stress that can decrease the yield of maize and wheat. Selection of a suitable application method and proper stage of crop for phosphorus (P) fertilizer has prime importance in better uptake of P and crop production. Among different application methods, soil and foliar application are widely adopted. In wheat and maize, knee height + tasseling and stem elongation + booting are critical stages towards P deficiency. That is why field trials were conducted to evaluate the supplemental effect of foliar P on maize and wheat yields. For that, 144 mM KH2PO4 was applied as foliar at knee height + tasseling and stem elongation + boot stages in maize and wheat, respectively. Soil application of 0, 20, 40 and 60 kg P ha-1 was done through broadcast and band methods. Results showed that foliar spray of 144 mM KH2PO4 at knee height + tasseling and stem elongation + boot stages in wheat and maize significantly enhanced grains yield and phosphorus use efficiency (PUE) where P was applied as banding or broadcast at the time of sowing. A significant decreasing trend in response to increasing soil P levels validated the efficacious role and suitability of foliar P. In conclusion, the use of P as foliar at knee height + tasseling and stem elongation + boot stages is an efficacious way to manage P fertilizer.

Ameliorative effect of co-application of Bradyrhizobium japonicum EI09 and Se to mitigate chromium stress in Capsicum annum L.

The present study was conducted to explore the potential of Bradyrhizobium japonicum EI09 (EI09) and selenium (Se) alone or in combination to mitigate hexavalent chromium (Cr6+) stress in Capsicum annum L. Chromium stressed plants exhibited significant reduction in biomass, chlorophyll content and gas exchange characteristics. The inoculated seedlings subjected to Cr6+stress showed improvement in growth, proline content, gas exchange attributes and total soluble proteins. Likewise, inoculated C. annum seedlings exhibited augmented activity of ascorbate peroxidase (APX), catalase (CAT), peroxidase (POD) and superoxide dismutase (SOD) under Cr6+ stress. The Cr6+ stress mitigation in inoculated seedlings was ascribed to reduction in malondialdehyde (MDA) content, hydrogen peroxide (H2O2) besides increase activity of flavonoids, proline, phenolic content along with modulation of antioxidative enzymes. The growth-enhancing attributes of bacteria such as indole acetic acid (IAA) content and 1-aminocyclopropane-1-carboxylate deaminase (ACCD) activity enhanced growth in Cr6+-stressed plants. Moreover, co-treatment of EI09 and 5 µM Se effectively mitigated Cr (VI) stress in C. annum plants. Current studies provide a novel insight into potential of B. japonicum EI09 and Se in reduction of Cr6+ toxicity in C. annum plants.

Chemical constituents of Cordia latifolia and their nematicidal activity.

Following nematicidal activity-guided isolation studies on the fruits, bark, and leaves of Cordia latifolia, two new constituents, cordinoic acid (=11-oxours-12-ene-23,28-dioic acid; 1) and cordicilin (=2-{[(E)-3-(3,4-dihydroxyphenyl)prop-2-enoyl]oxy}-3-[4-hydroxy-3-(stearoyloxy)phenyl]propanoic acid; 2) were isolated from the stem and leaves, respectively, together with nine known compounds, namely cordioic and cordifolic acid from the stem bark, latifolicin A-D and rosmarinic acid from the fruits, and cordinol and cordicinol from the leaves. Their structures were determined by means of spectroscopic analyses including 1D- and 2D-NMR techniques. The nematicidal activities of these constituents were determined against the root-knot nematode Meloidogyne incognita. Hundred percent mortality was caused by all of these after 72 h at a 0.125% concentration. Compound 1 and cordioic acid were most active and caused 100% mortality after 24 h at a 0.50% concentration. Furthermore, compound 2, the ester of rosemarinic acid, was found to be more active than the free acid.

Pentacyclic triterpenoids from the aerial parts of Lantana camara and their nematicidal activity.

Two new olean-12-ene triterpenoids, camarolic acid (1) and lantrigloylic acid (2), have been isolated from the aerial parts of Lantana camara, along with ten known triterpenes, namely, camaric acid, lantanolic acid, lantanilic acid, pomolic acid, camarinic acid, lantoic acid, camarin, lantacin, camarinin, and ursolic acid. The new compounds have been characterized as 3,25-epoxy-3alpha-hydroxy-22beta-{[(S)-3-hydroxy-2-methylidenebutanoyl]oxy}olean-12-en-28-oic acid (1) and 3,25-epoxy-3alpha-hydroxy-22beta-[(3-methylbut-2-enoyl)oxy]olea-9(11),12-dien-28-oic acid (2) through spectroscopic studies and a chemical transformation. Seven of the constituents, namely pomolic acid, lantanolic acid, lantoic acid, camarin, lantacin, camarinin, and ursolic acid, were tested for nematicidal activity against root-knot nematode Meloidogyne incognita. Pomolic acid, lantanolic acid, and lantoic acid showed 100% mortality at 1 mg/ml concentration after 24 h, while camarin, lantacin, camarinin, and ursolic acid exhibited 100% mortality at this concentration after 48 h. These results are comparable to those obtained with the conventional nematicide furadan (100% mortality at 1 mg/ml concentration after 24 h).

Description of Tylenchorhynchus qasimii sp. n. with a New Report of T. kegasawaiMinagawa, 1995 from Pakistan.

A new stunt nematode, from soil around the roots of coconut (Cocos nucifera L.) and rice (Oryza sativa L.) from Karachi, Pakistan, is described and illustrated as Tylenchorhynchus qasimii n. sp. This new species is characterized by having females with 3-4 head annules, anteriorly directed stylet knobs, absence of post anal extension, presence of rounded sperm filled spermatheca and conoid to bluntly rounded hemispherical tail terminus. Males are common. Also included is the record of T. kegasawai from around the roots of rice (O. sativa L.), a new report from Sindh, Pakistan.