The metabolism and excretion of the dipeptidyl peptidase 4 inhibitor [14C] cetagliptin in healthy volunteers.

The metabolism and excretion of cetagliptin were investigated in healthy male subjects after a single oral dose of 100mg/50µCi [14C] cetagliptin.The mean concentration-time profile of cetagliptin was similar to that of total radioactivity in plasma after oral administration of [14C] cetagliptin in healthy male subjects. Cetagliptin was rapidly absorbed after oral administration. Unchanged cetagliptin was the most abundant radioactive component in all matrices investigated. Approximately 53.13% of plasma AUC of total radioactivity was accounted for by cetagliptin. Each metabolite plasma AUC was not higher than 2.93% of plasma AUC of total radioactivity. By 336 h after administration, 91.68% of the administered radioactivity was excreted, and the cumulative excretion in the urine and faeces was 72.88% and 18.81%, respectively. The primary route of excretion of radioactivity was via the kidneys.Four metabolites were detected at trace levels, and it involved hydroxylated (M436-1 and M436-3), N- sulphate (M500), and N-carbamoyl glucuronic acid conjugates (M640B) of cetagliptin. These metabolites were detected also in plasma, urine, and faeces at low levels, except that metabolite M640B was not detected in faeces. All metabolites were observed with <10% of parent compound systemic exposure after oral administration.

Mass balance, pharmacokinetics and pharmacodynamics of intravenous HSK3486, a novel anaesthetic, administered to healthy subjects.

AIMS: This trial (NCT03751956) investigated the mass balance, pharmacokinetics and pharmacodynamics of HSK3486, a novel anaesthetic, in healthy subjects. METHODS: A single dose of 0.4 mg/kg [14 C]HSK3486 was administered to six healthy subjects. Blood, urine and faecal samples were collected, analysed for radioactivity, unchanged HSK3486 and profiled for metabolites. The Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale and vital signs were closely monitored during the study. RESULTS: The mean recovery of total radioactivity in excreta was 87.3% in 240 h, including 84.6% in urine and 2.65% in faeces. The exposure (AUC0-t ) of total radioactivity was much higher than that of unchanged HSK3486 in plasma, indicating there were circulating metabolites in plasma. The glucuronide conjugate of HSK3486 (M4) was found as the only major circulating metabolite in plasma (79.3%), while unchanged HSK3486 accounted for only 3.97% of the total radiation exposure. M4 also resulted in a longer estimated elimination half-life (t1/2 ) of total radioactivity than that of unchanged HSK3486 in plasma. Fortunately, the metabolite was detected to be not specific to red blood cells and was suggested to be nonhypnotic and nontoxic. All the subjects were quickly anaesthetized (2 min) after drug administration and woke up smoothly after a short time (5.5-14.1 min) with few residual effects. The only adverse event in the study was mild (grade 1) and consisted of hypotension. CONCLUSION: HSK3486 is a promising anaesthetic candidate with rapid onset of action and clear absorption, distribution, metabolism, excretion (ADME) processes. HSK3486 showed favourable pharmacokinetic characteristics, pharmacodynamic responses and safety at the study dose.

Glucuronidation of aurantio-obtusin: identification of human UDP-glucuronosyltransferases and species differences.

1. The aurantio-obtusin's glucuronide was detected when aurantio-obtusin was incubated with human liver microsomes (HLMs). Recombinant UGT isoforms screening experiment showed that UGT1A8 was the major isoform contributed to the glucuronidation. 2. The metabolic profiles for aurantio-obtusin in liver microsomes from different species were similar, however, the intrinsic clearance values (Vmax/Km) among the species were: Monkey > Human > Rat > Rabbit > Dog > Pig > Mouse > Guinea pig.

[Effects of long-term positioning tillage on13C assimilate distribution and grain yield formation in wheat]. / 长期定位耕作模式对小麦13CåŒåŒ–ç‰©åˆ†é å’Œç±½ç²’äº§é‡å½¢æˆçš„å½±å“.

To provide a theoretical basis and technical support for the high-yield and high-efficiency production of wheat, we examined the effects of different tillage patterns on wheat grain yield of Jimai 22 and the physiological mechanisms in an experiment with three treatments: 14 years in rotary tillage (R), minimal and no tillage (S), and minimal and no tillage with a 2-year subsoiling interval (SS). We assessed the light interception by wheat plant canopy, the distribution of photosynthate transport, and grain yield for the three cultivation modes. The results showed that leaf area index was significantly higher for SS treatment than the other treatments at 14-28 days after anthesis. The interception rate and amount of photosynthetically active radiation in the upper and middle layers of wheat canopy were significantly higher for SS treatment than R and S treatments at 21 days after anthesis. The contribution rate of grain assimilation and the distribution proportion of 13C assimilated in grain, and the maximum and average filling rates, were the highest under SS treatment. The 1000-kernel weight for SS treatment increased by 8.7% and 9.6%, and the grain yield increased by 14.2% and 19.4% compared with R and S treatments, respectively. SS treatment significantly improved light energy utilization by wheat canopy, promoted the accumulation and transport of dry matter, increased the grain-filling rate, increased grain weight, which together contributed to the highest grain yield. Therefore, SS was the optimal tillage pattern under the conditions of this experiment.

[Effects of N, P, and K application rates on distribution of 13C assimilates, starch accumulation in grains and fertilizer utilization of wheat]. / 氮磷钾施用量对小麦旗叶13CåŒåŒ–ç‰©åˆ†é ã€ç±½ç²’æ·€ç²‰ç§¯ç´¯å’Œè‚¥æ–™åˆ©ç”¨çš„å½±å“.

Clarifying the appropriate application rates of N, P, and K fertilizers and the physiological mechanisms of wheat under water-saving recharge irrigation in the North China Plain would provide a theoretical basis for formulating reasonable fertilization plans for high-yield and high-efficiency wheat production. We established four treatments with different amounts of nitrogen (N), phosphorus (P2O5), and potassium (K2O) application: 0, 0, and 0 kg·hm-2 (F0), 180, 75, and 60 kg·hm-2 (F1), 225, 120, and 105 kg·hm-2 (F2), and 270, 165, and 150 kg·hm-2 (F3). During the jointing and anthesis stages of wheat, the relative water content of each treatment in the 0-40 cm soil layer was replenished to 70%, to investigate the differences in wheat flag leaf photosynthetic characteristics, distribution of 13C assimilates, grain starch accumulation, and fertilizer utilization. The results showed that the relative chlorophyll content of flag leaves, photosynthetic and chlorophyll fluorescence parameters, 13C assimilate allocation in each organ, enzyme activities involved in starch synthesis, and starch accumulation in the F1 treatment were significantly higher than that in F0 treatment, which was an important physiological basis for the 20.9% increase in grain yield. The above parameters and yield in the F2 and F3 treatments showed no significant increase compared to F1 treatment, while fertilizer productivity and agronomic efficiency of N, P, and K decreased by 17.5%-58.4% and 12.7%-50.7%, respectively. Therefore, F1 could promote flag leaf photosynthetic assimilate production and grain starch accumulation under water-saving supplementary irrigation conditions, resulting in higher grain yield and fertilizer utilization efficiency.

[Effects of phosphorus application rate on distribution of 13C assimilates and spike formation in different til-lers of wheat with supplementary irrigation]. / 补灌条件下施磷量对小麦不同茎蘖13CåŒåŒ–ç‰©åˆ†é åŠå ¶æˆç©—çš„å½±å“.

To clarify the appropriate rate of phosphorus application and physiological mechanism for promoting wheat tillering and efficient utilization of phosphorus fertilizer with supplementary irrigation, we used 'Jimai 22' wheat variety as the test material, to set up three phosphorus application treatments, including low (90 kg P2O5·hm-2, P1), medium (135 kg P2O5·hm-2, P2), and high (180 kg P2O5·hm-2, P3) application rates, with no phosphorus application as the control (P0). We increased the relative soil water content of each treatment at join-ting stage and anthesis stage to 70%, and measured the area of tiller node, the content of endogenous hormones, the number of tillers in each tiller position, photosynthetic parameters, the distribution of 13C assimilates in each stem and tiller, as well as the grain yield and partial productivity of phosphate fertilizer. The results showed that compared with P0 and P1 treatments, P2 significantly increased the area of tiller node and the trans-zeatin (tZ), the photosynthetic parameters of the uppermost expanded leaves of the main stem, the total tillers per plant, and the distribution of 13C assimilates in each tiller. The number of ears per plant was increased by 0.51 and 0.36, and grain yield was increased by 40.3% and 13.2%, respectively. In P3 treatment, the number of tillers increased, but the panicles per plant, and the grain yield and phosphate fertilizer partial productivity decreased. Our results suggested that the moderate phosphorus treatment (135 kg·hm-2) under supplementary irrigation was suitable for high yield and high efficiency of wheat.

In vitro and in vivo pharmacokinetics, disposition, and drug-drug interaction potential of tinengotinib (TT-00420), a promising investigational drug for treatment of cholangiocarcinoma and other solid tumors.

Early-stage clinical evaluation of tinengotinib (TT-00420) demonstrated encouraging preliminary efficacies in multiple types of refractory cancers, including fibroblast growth factor receptors (FGFR) inhibitors relapsed cholangiocarcinoma (CCA), castrate-resistant prostate cancer (CRPC), and HR+/HER2- breast cancer and triple negative breast cancer (TNBC). To further evaluate drug-like properties of the drug candidate, it is imperative to understand its metabolism and pharmacokinetic properties. This manuscript presented the investigation results of in vitro permeability, plasma protein binding, metabolic stability, metabolite identification, and drug-drug interaction of tinengotinib. Preclinical ADME (absorption, distribution, excretion, and metabolism) studies in rats and dogs was also conducted using a radioactive labeled tinengotinib, [14C]tinengotinib. Tinengotinib was found to have high permeability and high plasma protein binding and equally distributed between blood and plasma. There were no unique metabolites in human liver microsomes and tinengotinib showed moderate hepatic clearance. Tinengotinib is neither a potential inhibitor nor an inducer of P450 enzymes at clinically relevant concentrations, and unlikely to cause drug-drug interactions when used in combination with other drugs mediated by a key transporter, either as victim or perpetrator. Taken together, tinengotinib demonstrated a minimal risk of clinically relevant drug-drug interactions. Tinengotinib showed good oral bioavailability and dose-dependent exposures in both rat and dog after oral administration. The total radioactivity was largely distributed in the gastrointestinal system and liver, and tinengotinib could not easily pass through the blood-brain barrier. The major drug-related component in rat and dog plasma was unchanged drug (>89 %) with primary route of elimination via feces (>93 % of the dose) and minor via renal excretion (<4 % of the dose). Tinengotinib metabolism is mediated largely by CYP3A4, with minor contributions from CYP2D6 and CYP2C8. Major metabolic pathways include oxidation, oxidative cleavage of the morpholine ring, glucuronide and glutathione conjugations. The overall preclinical pharmacokinetics profile supported the selection and development of tinengotinib as a clinical candidate.

Pharmacokinetics, metabolism, excretion and safety of iruplinalkib (WX-0593), a novel ALK inhibitor, in healthy subjects: a phase I human radiolabeled mass balance study.

BACKGROUND: Iruplinalkib is a novel anaplastic lymphoma kinase (ALK) inhibitor for the treatment of ALK-positive crizotinib-resistant NSCLC. RESEARCH DESIGN AND METHODS: A single oral dose of 120 mg/3.7 MBq [14C]iruplinalkib was administered to healthy subjects. Blood, urine and fecal samples were collected and analyzed for iruplinalkib and its metabolites. The safety of iruplinalkib was also assessed. RESULTS: Iruplinalkib was absorbed quickly and eliminated slowly from plasma, with a Tmax of 1.5 h and t1/2 of 28.6 h. About 88.85% of iruplinalkib was excreted at 312 h, including 20.23% in urine and 68.63% in feces. Seventeen metabolites of iruplinalkib were identified, and M3b (demethylation), M7 (cysteine conjugation), M11 (oxidative dehydrogenation and cysteine conjugation of M3b) and M12 (oxidative dehydrogenation and cysteine conjugation) were considered the prominent metabolites in humans. Iruplinalkib-related compounds were found to be covalently bound to proteins, accounting for 7.70% in plasma and 17.96% in feces, which suggested chemically reactive metabolites were formed. There were no serious adverse events observed in the study. CONCLUSIONS: Iruplinalkib was widely metabolized and excreted mainly through feces in humans. Unchanged iruplinalkib, cysteine conjugates and covalent protein binding products were the main drug-related compounds in circulation. Iruplinalkib was well tolerated at the study dose. TRIAL REGISTRATION: The trial is registered at ClinicalTrials.gov (Identifier: Anonymized).

Deglycosylation of liquiritin strongly enhances its inhibitory potential towards UDP-glucuronosyltransferase (UGT) isoforms.

The detailed mechanisms on licorice-drug interaction remain to be unclear. The aim of the present study is to investigate the inhibition of important UGT isoforms by two important ingredients of licorice, liquiritin, and liquiritigenin. The results showed that liquiritigenin exhibited stronger inhibition towards all the tested UGT isoforms than liquiritin. Data fitting using Dixon and Lineweaver-Burk plots demonstrated the competitive inhibition of liquiritigenin towards UGT1A1 and UGT1A9-mediated 4-MU glucuronidation reaction. The inhibition kinetic parameters (Ki ) were calculated to be 9.1 and 3.2 µM for UGT1A1 and UGT1A9, respectively. Substrate-dependent inhibition behaviour was also observed for UGT1A1 in the present study. All these results will be helpful for understanding the deep mechanism of licorice-drug interaction. However, when translating these in vitro parameters into in vivo situations, more complex factors should be considered, such as substrate-dependent inhibition of UGT isoforms, the contribution of UGT1A1 and UGT1A9 towards the metabolism of drugs, and many factors affecting the abundance of ingredients in the licorice.

Glycyrrhetinic acid exhibits strong inhibitory effects towards UDP-glucuronosyltransferase (UGT) 1A3 and 2B7.

The aim of the present study is to evaluate the inhibitory effects of liver UDP-glucuronosyltransferases (UGTs) by glycyrrhizic acid and glycyrrhetinic acid, which are the bioactive ingredients isolated from licorice. The results showed that glycyrrhetinic acid exhibited stronger inhibition towards all the tested UGT isoforms, indicating that the deglycosylation process played an important role in the inhibitory potential towards UGT isoforms. Furthermore, the inhibition kinetic type and parameters were determined for the inhibition of glycyrrhetinic acid towards UGT1A3 and UGT2B7. Data fitting using Dixon and Lineweaver-Burk plots demonstrated that the inhibition of UGT1A3 and UGT2B7 by glycyrrhetinic acid was best fit to competitive and noncompetitive type, respectively. The second plot using the slopes from Lineweaver-Burk plots versus glycyrrhetinic acid concentrations was employed to calculate the inhibition kinetic parameters (K(i)), and the values were calculated to be 0.2 and 1.7 µM for UGT1A3 and UGT2B7, respectively. All these results remind us the possibility of UGT inhibition-based herb-drug interaction. However, the explanation of these in vitro parameters should be paid more caution due to complicated factors, including the probe substrate-dependent UGT inhibition behaviour, environmental factors affecting the abundance of herbs' ingredients, and individual difference of pharmacokinetic factors.

Theory and application for the promotion of wheat production in China: past, present and future.

Food security is becoming a crucial concern worldwide. In this study, we focus on wheat - a staple crop in China - as a model to review its history, status quo and future scenarios, with regard to key production technologies and management practices for wheat production and associated food security issues since the new era in China: the post-1949 era. First, the dominant technologies and management practices over the past 60 years are reviewed. Secondly, we outline several key innovative technologies and their theoretical bases over the last decade, including (i) prohibiting excessively early senescence at a later growth stage to maintain viable leaves with higher photosynthetic capacity, (ii) postponing top dressing nitrogen application to balance carbon and nitrogen nutrition, and (iii) achieving both high yield and better grain quality mainly by increasing soil productivity and balancing the ratio of nutrient elements. Finally, concerns such as water shortages and excessive application of chemical fertilizers are presented. Nevertheless, under high negative conditions, including global warming, rapid population growth, decreasing amounts of arable land, increasing competition with cash crops and severe environmental pollution, we conclude that domestic food production will be able to meet Chinese demand in the mid to long term, because increasingly innovative technologies and improved management practices have been and may continue to be applied appropriately.

Arbidol exhibits strong inhibition towards UDP-glucuronosyltransferase (UGT) 1A9 and 2B7.

The aim of the present study was to investigate arbidol's inhibition towards UDP-glucuronosyltransferase (UGT) 1A9 and 2B7. The nonspecific probe substrate 4-methylumbelliferone (4-MU) and recombinant UGT enzymes (UGT1A9, UGT2B7) were firstly used to evaluate the inhibition of arbidol towards UGT1A9 and UGT2B7. Furthermore, specific substrates of UGT1A9 and UGT2B7 propofol and zidovudine (AZT) were used to determine the inhibition of arbidol towards UGT1A9 and UGT2B7. Inhibition type and inhibition kinetic parameters (Ki) were determined. In vitro-in vivo extrapolation (IV-IVE) was performed to predict in vivo DDI magnitude induced by arbidol. Arbidol was demonstrated to exhibit competitive inhibition towards UGT1A9 and UGT2B7 without substate-dependent behaviour. The inhibition kinetic parameters (Ki) were calculated to be 0.5 microM, 3.5 microM, 2.8 microM, 29.7 microM for UGT2B7-mediated 4-MU glucuronidation, UGT1A9-mediated 4-MU glucuronidation, UGT2B7-mediated AZT glucuronidation, and UGT1A9-mediated propofol glucuronidation, respectively. Using these parameters, the in vivo alteration of area under of concentration-time curve (AUC) was calculated to be 156%, 22%, 28% and 2.6%, respectively. Given that arbidol exhibits strong inhibition towards UGT1A9 and UGT2B7, clinical monitoring should be given when arbidol was co-administered with drugs mainly undergoing UGT1A9, UGT2B7-mediated metabolism.

[Mapping environmental vulnerability from ETM + data in the Yellow River Mouth Area].

The environmental vulnerability retrieval is important to support continuing data. The spatial distribution of regional environmental vulnerability was got through remote sensing retrieval. In view of soil and vegetation, the environmental vulnerability evaluation index system was built, and the environmental vulnerability of sampling points was calculated by the AHP-fuzzy method, then the correlation between the sampling points environmental vulnerability and ETM + spectral reflectance ratio including some kinds of conversion data was analyzed to determine the sensitive spectral parameters. Based on that, models of correlation analysis, traditional regression, BP neural network and support vector regression were taken to explain the quantitative relationship between the spectral reflectance and the environmental vulnerability. With this model, the environmental vulnerability distribution was retrieved in the Yellow River Mouth Area. The results showed that the correlation between the environmental vulnerability and the spring NDVI, the September NDVI and the spring brightness was better than others, so they were selected as the sensitive spectral parameters. The model precision result showed that in addition to the support vector model, the other model reached the significant level. While all the multi-variable regression was better than all one-variable regression, and the model accuracy of BP neural network was the best. This study will serve as a reliable theoretical reference for the large spatial scale environmental vulnerability estimation based on remote sensing data.

Optimized border irrigation delays winter wheat flag leaf senescence and promotes grain filling.

Border irrigation is still the main irrigation method in the Huang-Huai-Hai Plain of China (HPC), and the suitable irrigation border length for water saving and high yield under traditional irrigation is still unclear. Therefore, a 2-year traditional border irrigation experiment (2017-2019) was conducted on the HPC. Four border lengths were tested: 20 m (L20), 30 m (L30), 40 m (L40), and 50 m (L50). These treatments were given supplementary irrigation at jointing and anthesis. An exclusively rainfed condition formed the control treatment. Compared with other treatments, the activities of superoxide dismutase antioxidant and sucrose phosphate synthetase, and the contents of sucrose and soluble proteins after anthesis were higher in the L40 and L50 treatments, while the content of malondialdehyde content was lower. Therefore, the L40 treatment effectively delayed the decrease in the soil plant analysis development (SPAD) value and chlorophyll fluorescence characteristics, promoted grain filling, and achieved the highest thousand-grain weight. Compared with the L40 treatment, the grain yields of the L20 and L30 treatment were significantly reduced, while the water productivity of the L50 treatment was significantly reduced. These findings suggest that 40 m was the optimal border length for both high yield and water saving in this experiment. This study provides a simple and low-cost water-saving irrigation method for winter wheat in the HPC under traditional irrigation, which can help alleviate the pressure of agricultural water use.

Effects of planting density on photosynthetic characteristics of flag leaf and senescence of leaf and root under wide-width sowing condition.

To determine the optimal planting density under wide-width sowing condition, we investigated the effects of different planting densities on photosynthetic characteristics of flag leaves, senescence characteristics of flag lea-ves and roots, grain yield, and water use efficiency under four planting density levels, 90×104 plants·hm-2 (D1), 180×104 plants·hm-2 (D2), 270×104 plants·hm-2 (D3) and 360×104 plants·hm-2 (D4), in field condition set in Yanzhou, Shandong during the growing season of 2018-2019 and 2019-2020. The results showed that compared with D1 and D4 treatments, D2 treatment significantly improved photosynthetic characteristics of wheat flag leaves during grain filling, increased the activity of superoxide dismutase (SOD) and soluble protein content, reduced the malondialdehyde (MDA) content, and delayed the senescence of flag leaves and roots. Compared with other treatments, D2 treatment significantly increased root length, root surface area and root volume in 0-40 cm soil layer. Compared with D1, D3 and D4 treatments, the grain yield of D2 treatment was increased by 11.8%, 2.5%, 6.4% in 2018-2019 and 22.7%, 5.7%, 17.1% in 2019-2020, respectively. In addition, water use efficiency was increased by 9.2%, 8.8%, 14.2% in 2018-2019 and 21.1%, 6.2%, 21.5% in 2019-2020, respectively. The planting density at 180×104 plants·hm-2 improved photosynthetic characteristics of flag leaves and root morphology during filling stage, delayed plant senescence, increased grain number per spike and grain weight. Consequently, the highest grain yield and water use efficiency were obtained under D2 treatment, which was the optimal treatment under the experimental wide-width sowing condition.

Impacts of Fertilization Optimization on Soil Nitrogen Cycling and Wheat Nitrogen Utilization Under Water-Saving Irrigation.

Scholars have proposed the practice of split nitrogen fertilizer application (SNFA), which has proven to be an effective approach for enhancing nitrogen use efficiency. However, the combined effects of SNFA on wheat plant nitrogen use efficiency, ammonia (NH3) emission flux, as well as the rates of nitrification and denitrification in different ecosystems remain unclear. Meanwhile, few studies have sought to understand the effects of the split nitrogen fertilizer method under water-saving irrigation technology conditions on nitrogen loss. The current study assessed soil NH3 volatilization, nitrification, and denitrification intensities, as well as the abundance of nitrogen cycle-related functional genes following application of different treatments. Specifically, we applied a nitrogen rate of 240 kg⋅ha-1, and the following fertilizer ratios of the percent base to that of topdressing under water-saving irrigation: N1 (basal/dressing, 100/0%), N2 (basal/dressing, 70/30%), N3 (basal/dressing, 50/50%), N4 (basal/dressing, 30/70%), and N5 (basal/dressing, 0/100%). N3 treatment significantly reduced NH3 volatilization, nitrification, and denitrification intensities, primarily owing to the reduced reaction substrate concentration (NO3 - and NH4 +) and abundance of functional genes involved in the nitrogen cycle (amoA-AOB, nirK, and nirS) within the wheat-land soil. 15N tracer studies further demonstrated that N3 treatments significantly increased the grain nitrogen accumulation by 9.50-28.27% compared with that under other treatments. This increase was primarily due to an increase in the amount of nitrogen absorbed by wheat from soil and fertilizers, which was caused by an enhancement in total nitrogen uptake (7.2-21.81%). Overall, N3 treatment (basal/dressing, 50/50%) was found to effectively reduce nitrogen loss through NH3 volatilization, nitrification and denitrification while improving nitrogen uptake by wheat. Thus, its application will serve to further maximize the yield and provide a fertilization practice that will facilitate cleaner wheat production in the North China Plain.

Grain-filling characteristics and yield formation of wheat in two different soil fertility fields in the Huang-Huai-Hai Plain.

Clarifying factors that underpinning the variation in wheat yield components between high and middle soil fertility fields is critical to increase grain production and narrow yield gap for smallholder farming systems in the Huang-Huai-Hai Plain (3HP), which characterized by a large variation in soil fertility. Two-year field experiments were conducted to investigate wheat tillering, leaf photosynthesis, and grain filling characteristics in different soil fertility fields: high soil fertility field (HF) and middle soil fertility field (MF). Results showed that the spike formation rate in HF was 12.7%-13.0% higher than that in MF, leading to an 18.0%-19.8% increase in spike number. In addition, HF improved canopy light interception and leaf photosynthesis characteristics after anthesis and delayed leaf senescence, contributing to the increase in both the active grain filling period and grain filling rate. This resulted in a higher 1,000 grain weight in HF, which was 8.2%-8.3% higher than that in MF. Compared to MF, HF obtained higher yields at 9,840 kg ha-1 in 2017/18 and 11,462 kg ha-1 in 2018/19, respectively. In summary, higher spike number and 1,000-grain weight, which were mediated by spike-formation rate, maximization of light interception and improved leaf photosynthesis. These results would have important implications for narrowing yield gap between MF and HF in the 3HP.

Optimized border irrigation improved soil water content, increased winter wheat grain yield and water productivity.

Border irrigation is still the main irrigation method in the Huang-Huai-Hai Plain of China (HPC), we aimed to find a suitable border length to reduce the quantity of irrigation water through a traditional border irrigation system to alleviate groundwater depletion. A 2-year experiment (2017-2019) was conducted with four border lengths: 20 m (L20), 30 m (L30), 40 m (L40) and 50 m (L50); supplementary irrigation was implemented during jointing and anthesis. The results showed that compared with the L20 and L30 treatments, the L40 treatment did not significantly increase the total water consumption. Compared with the L50 treatment, the L40 treatment significantly reduced the water consumption of ineffective tillers from jointing to anthesis. There was no significant difference in flag leaf net photosynthetic rate (Pn) between L40 treatment and L50 treatment at 14-28 days after anthesis, which was 12.36% and 21.31% higher than L30 and L20 treatments respectively, and significantly increased dry matter accumulation after anthesis. Grain yield were the higher in the L40 and L50 treatments, while the water productivity (WP) was highest in the L40 treatment, which was 3.98%, 4.54% and 7.94% higher than L50, L30, and L20 treatments, respectively. Hence, the irrigation field treatments with a border length of 40 m were considered the most efficient, which provides a theoretical basis for optimizing the traditional irrigation border length in HPC.

Optimized nitrogen fertilizer application strategies under supplementary irrigation improved winter wheat (Triticum aestivum L.) yield and grain protein yield.

BACKGROUND: Exploring suitable split nitrogen management is essential for winter wheat production in the Huang-Huai-Hai Plain of China (HPC) under water-saving irrigation conditions, which can increase grain and protein yields by improving nitrogen translocation, metabolic enzyme activity and grain nitrogen accumulation. METHODS: Therefore, a 2-year field experiment was conducted to investigate these effects in HPC. Nitrogen fertilizer was applied at a constant total rate (240 kg/ha), split between the sowing and at winter wheat jointing growth stage in varying ratios, N1 (0% basal and 100% dressing fertilizer), N2 (30% basal and 70% dressing fertilizer), N3 (50% basal and 50% dressing fertilizer), N4 (70% basal and 30% dressing fertilizer), and N5 (100% basal and 0% dressing fertilizer). RESULTS: We found that the N3 treatment significantly increased nitrogen accumulation post-anthesis and nitrogen translocation to grains. In addition, this treatment significantly increased flag leaf free amino acid levels, and nitrate reductase and glutamine synthetase activities, as well as the accumulation rate, active accumulation period, and accumulation of 1000-grain nitrogen. These factors all contributed to high grain nitrogen accumulation. Finally, grain yield increase due to N3 ranging from 5.3% to 15.4% and protein yield from 13.7% to 31.6%. The grain and protein yields were significantly and positively correlated with nitrogen transport parameters, nitrogen metabolic enzyme activity levels, grain nitrogen filling parameters. CONCLUSIONS: Therefore, the use of split nitrogen fertilizer application at a ratio of 50%:50% basal-topdressing is recommended for supporting high grain protein levels and strong nitrogen translocation, in pursuit of high-quality grain yield.

Differences in Water Consumption of Wheat Varieties Are Affected by Root Morphology Characteristics and Post-anthesis Root Senescence.

Selecting high-yielding wheat varieties for cultivation can effectively increase water use efficiency (WUE) in the Huang-Huai-Hai Plain, where is threatened by increasing water shortages. To further identify the difference in water use and its relationship with root morphology and senescence characteristics, wheat varieties with different yield potentials-Yannong 1212 (YN), Jimai 22 (JM), and Liangxing 99 (LX)-were studied in a high-yielding wheat field. The water consumption percentage (CP) in YN decreased from planting to anthesis; however, crop evapotranspiration and CP increased from anthesis to maturity compared with JM and LX. In YN, a higher soil water consumption from anthesis to maturity in the 0-100 cm soil layer was partly attributed to the greater root weight density in the 20-60 cm soil layer. In topsoil (0-40 cm), root length density, root surface area density, and root diameter at 20 days after anthesis, root superoxide dismutase activity, and root triphenyl tetrazolium chloride reduction activity during mid grain filling stage were higher in YN than in JM and LX. YN had the highest grain yields of 9,840 and 11,462 kg ha-1 and increased grain yield and WUE by 12.0 and 8.4%, respectively, as compared with JM, and by 30.3 and 21.3%, respectively, as compared with LX. Ensuring more soil water extraction post-anthesis by increasing roots in the 20-60 cm soil profile, improving root morphology traits, and alleviating root senescence in the topsoil during mid-grain filling stage will assist in selecting wheat varieties with high yield and WUE.