Nutrient use efficiency (NUE) of wheat (Triticum aestivum L.) as affected by NPK fertilization.

Nutrient use efficiency is crucial for increasing crop yield and quality while reducing fertilizer inputs and minimizing environmental damage. The experiments were carried out in silty clay loam soil of Lalitpur, Nepal, to examine how different amounts of nitrogen (N), phosphorus (P), and potassium (K) influenced crop performance and nutrient efficiency indices in wheat during 2019/20 and 2020/21. The field experiment comprised three factorial randomized complete block designs that were replicated three times. N levels (100, 125, 150 N kg ha-1), P levels (25, 50, 75 P2O5 kg ha-1), and K levels (25, 50, 75 K2O kg ha-1) were three factors evaluated, with a total of 27 treatment combinations. Grain yields were significantly increased by N and K levels and were optimum @ 125 kg N ha-1 and @ 50 kg K2O ha-1 with grain yields of 6.33 t ha-1 and 6.30 t ha-1, respectively. Nutrient levels influenced statistically partial factor productivity, internal efficiency, partial nutrient budget, recovery efficiency, agronomic efficiency, and physiological efficiency of NPK for wheat. Nutrient efficiency was found to be higher at lower doses of their respective nutrients. Higher P and K fertilizer rates enhanced wheat N efficiencies, and the case was relevant for P and K efficiencies as well. Wheat was more responsive to N and K fertilizer, and a lower rate of P application reduced N and K fertilizer efficiency. This study recommends to use N @ 125 kg ha-1, P2O5 @ 25 kg ha-1 and K2O @ 50 kg ha-1 as an optimum rate for efficient nutrient management in wheat in mid-hills of Nepal.

Co-application of Se and a biostimulant at different wheat growth stages: Influence on grain development.

An appropriate selenium intake can be beneficial for human health. Se-biofortified food in Se-deficient regions is becoming an increasingly common practice but there are still issues to be addressed regarding the observed Se-induced toxicity to the plant. In this respect, plant biostimulants are used to enhance nutrition efficiency, abiotic stress tolerance and crop quality. In this work, the efficacy of a plant biostimulant to counteract the Se-induced stress in wheat plants is experimentally assessed. The co-application of different Se-biofortification treatments and the biostimulant at different growth stages (tillering or heading stage) was investigated. The use of micro focused X-ray spectroscopy allows us to confirm organic Se species to be the main Se species found in wheat grain and that the proportion of organic Se species is only slightly affected by the Se application stage. Our study proves that the biostimulant had a key role in the enhancement of both the amount of grains produced per spike and their dry biomass without hindering Se enrichment process, neither diminishing the Se concentration nor massively disrupting the Se species present. This information will be useful to minimize both plant toxicity and economic cost towards a more effective and plant healthy selenium supplementation.

Different methods of silicon application attenuate salt stress in sorghum and sunflower by modifying the antioxidative defense mechanism.

Soil salinization is the most common abiotic stress limiting agricultural productivity worldwide. Recent research has suggested that the application of silicon (Si) has beneficial effects against salt stress in sorghum (Sorghum bicolor L. Moench) and sunflower (Helianthus annuus L.) by regulating the antioxidant system, mineral nutrients, and other important mechanisms. However, whether these effects can be achieved through foliar application of Si, or whether Si application affects Si-accumulating (e.g., sorghum), and intermediate-Si-accumulating (e.g., sunflower) plant species differently, remains unclear. This study investigated different methods of Si application in attenuating the detrimental effects of salt stress, based on the biological responses of two distinct species of Si accumulators, under greenhouse conditions. Two pot experiments were designed as a factorial (2 × 4), randomized complete blocks design (RCBD) with control and salt-stress groups (0 and 100 mmol.L-1 NaCl), and four Si-treatment groups: control (no Si), foliar application (28.6 mmol.L-1), root application (2 mmol.L-1), and combined foliar and root applications. Our results showed that the harmful effects of salt stress were attenuated by Si treatments in both plant species, which decreased Na+ uptake and lipid peroxidation, and increased Si and K+ uptake, relative leaf water content, antioxidant enzyme activities, leaf area, and shoot dry matter. These results were more prominent when Si was applied via nutrient solution in the sorghum plants, and the combined foliar and root applications of Si in sunflower plants. In addition, foliar application of Si alone is an efficient alternative in attenuating the effects of salinity in both plant species when Si is not available in the growth medium. These results suggest that the Si application method plays an important role in Na+ detoxification by modifying the antioxidative defense mechanism, which could actively mediate some important physiological and biochemical processes and helps to increase the shoot dry matter production in sorghum and sunflower plants under salt stress.

Selenium-silicon (Se-Si) induced modulations in physio-biochemical responses, grain yield, quality, aroma formation and lodging in fragrant rice.

Fragrant rice is a high-valued quality rice type which is gaining much popularity over the globe due to its better cooking qualities and special aromatic characteristics. Selenium (Se) and silicon (Si) could improve the growth and yield of rice; however, the combine effects of Se and Si (Se-Si treatments) on rice grain quality, aroma and lodging in fragrant rice were rarely investigated. The pot and field experiments were conducted with two fragrant rice cultivars i.e., Xiangyaxiangzhan and Yuxiangyouzhan, grown under three Se levels i.e., 0, 120, and 240 mg kg-1 of soil (for pot experiment) and 0, 300, and 600 kg ha-1 (for field experiment) regarded as LSe, MSe and HSe, respectively and two Si levels i.e., 0 and 60 mg kg-1 of soil (for pot experiment) and 0 and 150 kg ha-1 (for field experiment) regarded as -Si and +Si, respectively. Results depicted that the Se-Si treatments regulated head rice yield, grain yield and yield related traits and the HSe+Si treatment sustainably improved the grain yield and head rice yield by regulating plant growth, antioxidant response and malondialdehyde (MDA) contents in fragrant rice. The Se-Si treatments also improved the grain 2AP contents owing to regulation in the proline, pyrroline-5-carboxylate (P5C) and γ-aminobutyric acid (GABA) contents. Besides, Se-Si treatments also regulated the grain quality attributes and influenced the plant Se contents. Moreover, the Si mitigated Se-induced lodging resulted from changes in the lodging parameters i.e., lodging index, fresh weight per tiller, pushing resistance force, plant height and bending moment. Overall, the Se and Si application improved the grain yield and regulated the dry weight accumulation, antioxidant attributes and quality attributes. Meanwhile, the Si application mitigated the negative effect of Se-induced lodging in fragrant rice.

Integrated use of straw mulch with nitrogen fertilizer improves soil functionality and soybean production.

Mulching can effectively maintain and improve soil health and functionality. The mechanisms, however, have not been fully elucidated. Therefore, the effects of temperature on the biogeochemical properties of soil were investigated in the present study in relation to nitrogen management and soil functionality. The results of the 3-year field experiments showed that integrated straw mulch (S) and nitrogen fertilizer (N) treatments enhanced the activities of soil urease, invertase, alkaline phosphatase, and catalase by >1.8, 2.1, 2.0 and 1.4 fold, respectively, compared with the control treatment. Furthermore, these treatments increased soil available N by 28%, phosphorus by 45%, and potassium by 55%. In general, the soil organic carbon, dissolved carbon and labile organic carbon content in the treated plot were approximately 1.2-2.9 folds greater than in the control plot. These improvements in soil fertility and carbon indices increased the biomass and grain yield of soybean (67 and 75%, respectively) during the three-year study period. During 2015-2017, the straw mulch and nitrogen fertilizer treatment increased the soil moisture (23%) and decreased the soil temperature (8%) in comparison to the control in the 0-0.2 m soil depth and, therefore, improved soil enzyme activities, nutrient availability, and carbon stocks, and ultimately, soil functionality and sustainability, in the semiarid region.

Compared to antioxidants and polyamines, the role of maize grain-derived organic biostimulants in improving cadmium tolerance in wheat plants.

Recently, the strategy of seed soaking has been successfully applied using extracts from different plant parts for healthy growth of plant under different environmental stresses. Compared to antioxidants like ascorbic acid (AsA) and glutathione (GSH) or polyamines (PAs) like spermine (SPM), spermidine (SPD), and putrescine (PUT), the effects of seed soaking using maize grain extract (MGE) on the biomass, productivity, phytohormones, and antioxidant defense system and its different components were examined with Cd2+-stressed wheat plants. In a preliminary study, seed soaking using AsA + GSH or PUT + SPD + SPM was more effective in increasing shoot fresh and dry weights, SPAD chlorophyll, and grain yield, and reducing malondialdehyde (MDA) content than individuals. In addition, MGE at 2% was more efficient than other concentrations. Therefore, they were selected for the main study. In the main study, compared to the control, seed soaking in AsA + GSH, PUT + SPD + SPM or MGE had positive effects on plant growth, yield, photosynthetic efficiency, contents and redox states of AsA and GSH, contents of PAs and plant hormones to varying degrees. Proline content and its metabolism enzymes activity, contents of soluble protein, N-compounds, soluble sugars, and α-tocopherol (α-TOC), and activities of antioxidant enzymes were not affected. However, contents of MDA and hydrogen peroxide (H2O2) were significantly reduced under normal conditions. Under Cd2+ stress (1.2 mM), along with the detrimental increases in the contents of MDA, H2O2 and Cd2+, contents of N-compounds, soluble sugars, proline content and its metabolism enzymes activities, AsA and GSH and their redox states, and polyamines, and activities of antioxidant enzymes were increased. In contrast, plant growth and yield, photosynthetic efficiency, soluble protein, and plant hormones were significantly reduced compared to the control. However, all of these attributes were significantly improved to varying degrees along with reduced contents of Cd2+, MDA, and H2O2 by seed soaking in AsA + GSH, PUT + SPD + SPM or MGE compared to the Cd2+-stressed control. Compared to AsA + GSH or PUT + SPD + SPM, seed soaking in MGE at 2% conferred the best results. Therefore, it is recommended to soak wheat seeds using MGE to improve plant growth and productivity by restricting the inhibitory influences of oxidative stress induced by Cd2+ stress.

Macronutrients influence yield and oil quality of hybrid maize (Zea mays L.).

In the present two-year study, an attempt was made to estimate the grain yield, grain nutrient uptake, and oil quality of three commonly grown maize (Zea mays L.) hybrids fertilized with varied levels of nitrogen (N), phosphorus (P) and potassium (K). Results obtained from both the experimental years indicated that application of 125% of recommended dose of fertilizer (RDF) recorded maximum grain yield (10.37 t ha-1; 124% higher than control). When compared with 100% RDF, grain yield reduction with nutrient omission was 44% for N omission, 17% for P omission, and 27% for K omission. Nitrogen uptake was increased with increasing NPK levels up to 150% RDF that was statistically at par (p ≥ 0.01) with 125% RDF. Increasing trend in P and K uptake was observed with successive increase in NPK levels up to 125% RDF, above which it declined. The protein content was significantly higher in grains of var. P 3396 with 125% RDF. Nutrient management has significant (p ≤ 0.01) role in the grain oil content. Saturated fatty acids (palmitic, stearic and arachidic acid) content decreased, and unsaturated fatty acid (oleic, linoleic and linolenic acid) increased with increasing NPK levels. The average oleic acid desaturation and linoleic acid desaturation ratios were increased with increasing NPK levels up to 100 and 125% RDF, respectively. However, average monounsaturated fatty acids (MUFA): poly-unsaturated fatty acids (PUFA), saturated: unsaturated as well as linoleic: linolenic acid ratios were increased on receiving 75% RDF, and beyond that it showed decreasing trend. The omission of K had the highest inhibitory effect on corn oil quality followed by N and P omission.

A chemical genetic screen reveals that iminosugar inhibitors of plant glucosylceramide synthase inhibit root growth in Arabidopsis and cereals.

Iminosugars are carbohydrate mimics that are useful as molecular probes to dissect metabolism in plants. To analyse the effects of iminosugar derivatives on germination and seedling growth, we screened a library of 390 N-substituted iminosugar analogues against Arabidopsis and the small cereal Eragrostis tef (Tef). The most potent compound identified in both systems, N-5-(adamantane-1-yl-ethoxy)pentyl- L-ido-deoxynojirimycin (L-ido-AEP-DNJ), inhibited root growth in agar plate assays by 92% and 96% in Arabidopsis and Tef respectively, at 10 µM concentration. Phenocopying the effect of L-ido-AEP-DNJ with the commercial inhibitor (PDMP) implicated glucosylceramide synthase as the target responsible for root growth inhibition. L-ido-AEP-DNJ was twenty-fold more potent than PDMP. Liquid chromatography-mass spectrometry (LC-MS) analysis of ceramide:glucosylceramide ratios in inhibitor-treated Arabidopsis seedlings showed a decrease in the relative quantity of the latter, confirming that glucosylceramide synthesis is perturbed in inhibitor-treated plants. Bioinformatic analysis of glucosylceramide synthase indicates gene conservation across higher plants. Previous T-DNA insertional inactivation of glucosylceramide synthase in Arabidopsis caused seedling lethality, indicating a role in growth and development. The compounds identified herein represent chemical alternatives that can overcome issues caused by genetic intervention. These inhibitors offer the potential to dissect the roles of glucosylceramides in polyploid crop species.

Review on the significance of chlorine for crop yield and quality.

The chloride concentration in the plant determines yield and quality formation for two reasons. First, chlorine is a mineral nutrient and deficiencies thereof induce metabolic problems that interfere with growth. However, due to low requirement of most crops, deficiency of chloride hardly appears in the field. Second, excess of chloride, an event that occurs under chloride-salinity, results in severe physiological dysfunctions impairing both quality and yield formation. The chloride ion can effect quality of plant-based products by conferring a salty taste that decreases market appeal of e.g. fruit juices and beverages. However, most of the quality impairments are based on physiological dysfunctions that arise under conditions of chloride-toxicity: Shelf life of persimmon is shortened due to an autocatalytic ethylene production in fruit tissues. High concentrations of chloride in the soil can increase phyto-availability of the heavy metal cadmium, accumulating in wheat grains above dietary intake thresholds. When crops are cultivated on soils that are moderately salinized by chloride, nitrate fertilization might be a strategy to suppress uptake of chloride by means of an antagonistic anion-anion uptake competition. Overall, knowledge about proteins that catalyse chloride-efflux out of the roots or that restrict xylem loading is needed to engineer more resistant crops.

Effects of Zn, macronutrients, and their interactions through foliar applications on winter wheat grain nutritional quality.

Although application of Zn combined with macronutrients (K, P, and N) can be used to fortify wheat grain with Zn, little is known about their interactions when foliar application is employed or the influences of common soil fertility management practices (e.g. N and straw management) on their efficiency. Therefore, the effects of foliar-applied Zn and N, P, or K on grain nutritional quality (especially Zn) were investigated in wheat grown under different soil N rates at two sites with (Sanyuan) or without (Yangling) employing straw return. A 4-year-long field experiment was also conducted to evaluate the environmental stability of the foliar formulations. Across 6 site-years, foliar Zn application alone or combined with N, P, or K fertilizers resulted in 95.7%, 101%, 67.9% and 121% increases in grain Zn concentration, respectively. In terms of increasing grain Zn concentration, foliar-applied Zn positively interacted with N (at Sanyuan) and K (at Yangling), but negatively interacted with P at any condition tested, suggesting depressive effects of foliarly-applied P on physiological availability of Zn. Although these interaction effects were the major factor that governing the efficiency of foliar-applied Zn combined with N, P, or K on grain Zn concentration, the magnitude of the increase/decrease in grain Zn (-3.96~5.71 mg kg-1) due to these interactions was much less than the average increases following Zn+K (31.3), Zn+P (18.7), and Zn+N (26.5 mg kg-1) treatments relative to that observed in foliar Zn-only treatment. The combined foliar application of Zn with N, P, or K did not cause any adverse impact on grain yield and other nutritional quality and in some cases slightly increased grain yield and macronutrient concentrations. Grain phytic acid:Zn molar ratios were respectively 52.0%, 53.1%, 43.4% and 63.5% lower in the foliar Zn, Zn+N, Zn+P and Zn+K treatments than in the control treatment. These effects were consistent over four years and across three soil N rates. Overall, combined foliar application of Zn with N, P, or K can successfully fortify wheat grain with Zn (above 40 mg kg-1), and including Zn in foliar N or K application are preferred for practically increasing dietary Zn intake.

Electron Paramagnetic Resonance (EPR) Spectroscopy in Studies of the Protective Effects of 24-Epibrasinoide and Selenium against Zearalenone-Stimulation of the Oxidative Stress in Germinating Grains of Wheat.

These studies concentrate on the possibility of using selenium ions and/or 24-epibrassinolide at non-toxic levels as protectors of wheat plants against zearalenone, which is a common and widespread mycotoxin. Analysis using the UHPLC-MS technique allowed for identification of grains having the stress-tolerant and stress-sensitive wheat genotype. When germinating in the presence of 30 µM of zearalenone, this mycotoxin can accumulate in both grains and hypocotyls germinating from these grains. Selenium ions (10 µM) and 24-epibrassinolide (0.1 µM) introduced together with zearalenone decreased the uptake of zearalenone from about 295 to 200 ng/g and from about 350 to 300 ng/g in the grains of tolerant and sensitive genotypes, respectively. As a consequence, this also resulted in a reduction in the uptake of zearalenone from about 100 to 80 ng/g and from about 155 to 128 ng/g in the hypocotyls from the germinated grains of tolerant and sensitive wheat, respectively. In the mechanism of protection against the zearalenone-induced oxidative stress, the antioxidative enzymes-mainly superoxide dismutase (SOD) and catalase (CAT)-were engaged, especially in the sensitive genotype. Electron paramagnetic resonance (EPR) studies allowed for a description of the chemical character of the long-lived organic radicals formed in biomolecular structures which are able to stabilize electrons released from reactive oxygen species as well as the changes in the status of transition paramagnetic metal ions. The presence of zearalenone drastically decreased the amount of paramagnetic metal ions-mainly Mn(II) and Fe(III)-bonded in the organic matrix. This effect was particularly found in the sensitive genotype, in which these species were found at a smaller level. The protective effect of selenium ions and 24-epibrassinolide originated from their ability to inhibit the destruction of biomolecules by reactive oxygen species. An increased ability to defend biomolecules against zearalenone action was observed for 24-epibrassinolide.

Genotypic-dependent effects of N fertilizer, glutathione, silicon, zinc, and selenium on proteomic profiles, amino acid contents, and quality of rice genotypes with contrasting grain Cd accumulation.

Soil heavy metal (HM) contamination has posed a serious problem for safe food production. For restricting the translocation of HM into grain, many proteins were regulated to involve in the process. To identify these proteins, 2D-based proteomic analysis was carried out using different rice genotypes with distinct Cd accumulation in grains and as affected by an alleviating regulator (AR) in field experiments. AR application improved grain quality, with increased contents in Glu, Cys, His, Pro, and protein. Twenty-six low-grain HM accumulation-associated protein species were identified and categorized as physiological functions via two-dimensional gel electrophoresis (2DE) and mass spectrometry. Among these proteins, 8, 9, and 9 proteins exhibited higher accumulation, lower accumulation, and unchanged accumulation, respectively, in Xiushui817 (low accumulator) vs R8097 (high accumulator) under control conditions but showed differential accumulation patterns after AR application. These proteins included sucrose synthase 3, alanine aminotransferase, glutelin, cupin family protein, and zinc finger CCCH domain-containing protein 32. The differential expression of these protein species might contribute to decreased HM accumulation in grain via decreasing the protein accumulation which had high affinity to HM or regulating energy metabolism and signal transduction. Our findings provide valuable insights into the mechanisms of low-grain HM accumulation in rice and possible utilization of candidate protein species in developing low-grain HM accumulation genotypes.

A combined application of biochar and phosphorus alleviates heat-induced adversities on physiological, agronomical and quality attributes of rice.

Present study examined the influence of high-temperature stress and different biochar and phosphorus (P) fertilization treatments on the growth, grain yield and quality of two rice cultivars (IR-64 and Huanghuazhan). Plants were subjected to high day temperature-HDT (35 °C ± 2), high night temperature-HNT (32 °C ± 2), and control temperature-CT (28 °C ± 2) in controlled growth chambers. The different fertilization treatments were control, biochar alone, phosphorous (P) alone and biochar + P. High-temperature stress severely reduced the photosynthesis, stomatal conductance, water use efficiency, and increased the leaf water potential of both rice cultivars. Grain yield and its related attributes except for number of panicles, were reduced under high temperature. The HDT posed more negative effects on rice physiological attributes, while HNT was more destructive for grain yield. High temperature stress also hampered the grain appearance and milling quality traits in both rice cultivars. The Huanghuazhan performed better than IR-64 under high-temperature stress with better growth and higher grain yield. Different soil fertilization treatments were helpful in ameliorating the detrimental effects of high temperature. Addition of biochar alone improved some growth and yield parameters but such positive effects were lower when compared with the combined application of biochar and P. The biochar+P application recorded 7% higher grain yield (plant(-1)) of rice compared with control averaged across different temperature treatments and cultivars. The highest grain production and better grain quality in biochar+P treatments might be due to enhanced photosynthesis, water use efficiency, and grain size, which compensated the adversities of high temperature stress.

Inhibition of cereal rust fungi by both class I and II defensins derived from the flowers of Nicotiana alata.

Defensins are a large family of small, cysteine-rich, basic proteins, produced by most plants and plant tissues. They have a primary function in defence against fungal disease, although other functions have been described. This study reports the isolation and characterization of a class I secreted defensin (NaD2) from the flowers of Nicotiana alata, and compares its antifungal activity with the class II defensin (NaD1) from N. alata flowers, which is stored in the vacuole. NaD2, like all other class I defensins, lacks the C-terminal pro-peptide (CTPP) characteristic of class II defensins. NaD2 is most closely related to Nt-thionin from N. tabacum (96% identical) and shares 81% identity with MtDef4 from alfalfa. The concentration required to inhibit in vitro fungal growth by 50% (IC50 ) was assessed for both NaD1 and NaD2 for the biotrophic basidiomycete fungi Puccinia coronata f. sp. avenae (Pca) and P. sorghi (Ps), the necrotrophic pathogenic ascomycetes Fusarium oxysporum f. sp. vasinfectum (Fov), F. graminearum (Fgr), Verticillium dahliae (Vd) and Thielaviopsis basicola (Tb), and the saprobe Aspergillus nidulans. NaD1 was a more potent antifungal molecule than NaD2 against both the biotrophic and necrotrophic fungal pathogens tested. NaD2 was 5-10 times less effective at killing necrotrophs, but only two-fold less effective on Puccinia species. A new procedure for testing antifungal proteins is described in this study which is applicable to pathogens with spores that are not amenable to liquid culture, such as rust pathogens. Rusts are the most damaging fungal pathogens of many agronomically important crop species (wheat, barley, oats and soybean). NaD1 and NaD2 inhibited urediniospore germination, germ tube growth and germ tube differentiation (appressoria induction) of both Puccinia species tested. NaD1 and NaD2 were fungicidal on Puccinia species and produced stunted germ tubes with a granular cytoplasm. When NaD1 and NaD2 were sprayed onto susceptible oat plants prior to the plants being inoculated with crown rust, they reduced the number of pustules per leaf area, as well as the amount of chlorosis induced by infection. Similar to observations in vitro, NaD1 was more effective as an antifungal control agent than NaD2. Further investigation revealed that both NaD1 and NaD2 permeabilized the plasma membranes of Puccinia spp. This study provides evidence that both secreted (NaD2) and nonsecreted (NaD1) defensins may be useful for broad-spectrum resistance to pathogens.

Treatment with the herbicide TOPIK induces oxidative stress in cereal leaves.

Leaf disks as well as intact 7-day-old plants of winter wheat (Triticum aestivum L., cv. Mironovskaya 808), winter rye (Secale cereale L., cv. Estafeta Tatarstana), and maize (Zea mays L., cv. Kollektivnyi 172MV), were treated with the aryloxyphenoxypropionate class herbicide TOPIK, concentrate-emulsion (active ingredient is clodinafop-propargyl (CP), 8-800µg/L), and the effects of short-term action (up to 3h) and long-term aftereffect (up to 3days) on physiological and biochemical indices related to oxidative stress development were studied. The herbicide induced changes, predominantly increases in lipid peroxidation (LPO) intensity, superoxide anion O2(-) generation, total antioxidant activity (AOA), and catalase (CAT) and ascorbate peroxidase (APOX) activity, although the response by plants was nonlinear and depended on the herbicide concentration and duration of treatment. The highest level of generation of O2(-) was observed in the leaves of maize and winter wheat treated by 800µg/L CP, both in the short- and long-term. As TOPIK concentration increased, so too did LPO and AOA in leaves, confirming the presence of oxidative stress in the cells of all three cereals. Antioxidant enzymes were most active in winter rye and wheat, and least active in maize indicating a protective antioxidant mechanism in the first two cereals.

The effect of extremely diluted agitated gibberellic acid (10e-30) on wheat stalk growth--a two researcher pilot study.

OBJECTIVE: Use of a wheat growth bio assay after 7 days in research on homeopathic dilutions of gibberellic acid. METHODS: Grains of winter wheat (Triticum aestivum, Capo variety) were observed under the influence of extremely diluted gibberellic acid (10(-30)) prepared by stepwise dilution and agitation according to a protocol derived from homeopathy (30×). Analogously prepared water was used for control. In a two centre study, 3 experiments with a total of 4880 grains were performed. RESULTS: Data were found to be rather homogeneous within the control group as well as within the verum group in general. Germination rates were around 95%, with no significant difference between verum and control group (p>0.05). Mean stalk lengths (mm) were 40.63±20.96 for the verum and 44.33±21.11 for the control group (mean±S.D.) at grain level (N=2440 per group) and ±5.33 and ±5.89, respectively at dish level (122 cohorts of 20 grains per treatment group). In other words, verum stalk length (91.65%) was 8.35% smaller than control stalk length (100%). This difference is statistically highly significant (p<0.001) and was found by both researchers involved independently. CONCLUSION: These results suggest that there was an influence of gibberellic acid 30× on wheat seedling development, i.e. the wheat growth bio assay can be a useful tool for further experiments on homeopathic dilutions of gibberellic acid.

Selenium protects sorghum leaves from oxidative damage under high temperature stress by enhancing antioxidant defense system.

Oxidative stress is commonly induced when plants are grown under high temperature (HT) stress conditions. Selenium often acts as an antioxidant in plants; however, its role under HT-induced oxidative stress is not definite. We hypothesize that selenium application can partly alleviate HT-induced oxidative stress and negative impacts of HT on physiology, growth and yield of grain sorghum [Sorghum bicolor (L.) Moench]. Objectives of this study were to investigate the effects of selenium on (a) leaf photosynthesis, membrane stability and antioxidant enzymes activity and (b) grain yield and yield components of grain sorghum plants grown under HT stress in controlled environments. Plants were grown under optimal temperature (OT; 32/22°C daytime maximum/nighttime minimum) from sowing to 63 days after sowing (DAS). All plants were foliar sprayed with sodium selenate (75mgL(-1)) at 63 DAS, and HT stress (40/30°C) was imposed from 65 DAS through maturity. Data on physiological, biochemical and yield traits were measured. High temperature stress decreased chlorophyll content, chlorophyll a fluorescence, photosynthetic rate and antioxidant enzyme activities and increased oxidant production and membrane damage. Decreased antioxidant defense under HT stress resulted in lower grain yield compared with OT. Application of selenium decreased membrane damage by enhancing antioxidant defense resulting in higher grain yield. The increase in antioxidant enzyme activities and decrease in reactive oxygen species (ROS) content by selenium was greater in HT than in OT. The present study suggests that selenium can play a protective role during HT stress by enhancing the antioxidant defense system.

Effects of structure and xylanase treatment of brewers' spent grain on performance and nutrient availability in broiler chickens.

1. A factorial (2 x 3) feeding trial was set up to investigate the effects of coarse or finely ground brewers' spent grain (BSG) and xylanase treatment, either with no xylanase, top-dressed with xylanase or pre-treated with xylanase. 2. The experimental diets shared the same basal formulation and were fed to male broiler chickens (Ross 308) housed in individual cages from 12 to 29 d of age. 3. Xylanase pre-treatment reduced the dietary concentration of arabinoxylan by 15-30%. Pellet durability increased when BSG was ground. 4. Feed utilisation was significantly higher (6%) when the birds were given coarse BSG rather than ground BSG, whereas there was no significant effect of enzyme treatment. Apparent metabolisable energy was unaffected by the dietary treatments. 5. The overall starch digestibility was high (99%), with no dietary differences, whereas ileal protein digestibility was low (57%). Xylanase top-dressing tended to improve ileal protein digestibility but, in general, xylanase treatment had no major effect on overall performance in male broilers given diets with BSG.

Se(IV) phytotoxicity for monocotyledonae cereals (Hordeum vulgare L., Triticum aestivum L.) and dicotyledonae crops (Sinapis alba L., Brassica napus L.).

The phytotoxicity of Se(IV) was determined through root and shoot growth inhibition, biomass (dry (DM), fresh (FM)) production, water content, photosynthetic pigment (chlorophyll a, chlorophyll b and carotenoids) levels and Se accumulation in the roots and shoots. The sensitivities of monocotyledonae (Hordeum vulgare, Triticum aestivum) and dicotyledonae plants (Sinapis alba, Brassica napus) were also compared. Except for H. vulgare, Se(IV) inhibited root growth more than shoot growth. As for biomass production, Se reduced both FM and DM of all studied plants' roots. Although in shoots FM was decreased with increased Se concentration, DM was reduced only in monocotyledonae plants (H. vulgare, T. aestivum). No significant differences between roots and shoots were confirmed for the DM/FM relationship, except for S. alba seedlings. In all of the tested plants, except for B. napus, chlorophyll b was the strongest reduced pigment. Accumulation of Se was higher in the roots than in the shoots of all studied plants. Selenium concentration in the roots was at least 3-times higher than that in controls. Se(IV) accumulation in the shoots was not significantly different from that in controls. The exception was confirmed only for B. napus (87 mg Se(IV)l(-1)) and T. aestivum (36 mg Se(IV)l(-1)).

Genetic analysis of agricultural traits in rice related to phosphorus efficiency.

Relative tillering ability, available spike, biomass, and grain yield of P1, P2, F1, and F(2,3) were used to study the genetic development of rice related to phosphorus efficiency with a quantitative genetic model. The results indicated that under a low-P condition, the relative tillering ability and the relative available spike were apt to the additivity-dominance-epistasis model with two couples of major genes, between which additive, dominant and epistatic effects existed, and with multi-gene modifications. Their maximum major gene effect mostly indicated additivity, but sub-maximum major gene effect mostly indicated dominance. Relative biomass and grain yield were apt to the additivity-dominance-epistasis and multi-genes model. The heritabilities of the major genes were 60.08% and 37.70%, and those of the multi-genes were 32.15% and 58.9%, respectively. This meant that the heritabilities of the relative tillering ability, the relative available spike, and the relative biomass were high, so they were ideal indexes for rice breeding tolerating to low-P stress; whereas, the heritability of the relative grain yield was low, which meant that the grain yield was easily affected by the environment.