Jointing Stage Research Articles

Response Characteristics of Growth Properties and Yield of Strong-gluten Winter Wheat Upon the Water-saving Supply Condition

Identification of the wheat cultivars with excellent strong-gluten property and the related stress resistance-associated physiological mechanism can provide practical basis for guiding the high-quality wheat cultivation under water-saving conditions. With an aim to understand the growth characteristics and yield traits of strong-gluten wheat in Hebei plain, this study investigated the photosynthetic characteristics, contents of osmotic regulatory substances (proline and soluble sugar), nitrogen uptake and accumulation, population characteristics and yield of strong-gluten wheat varieties (Gaoyou 5218, Shiyou 20 and Shishi Luan 02-1), three ones with demonstration potential, in response to reduction of water supply (irrigated prior to seed sowing and joint stage over the whole growth period). Results showed that compared with control (a common-gluten type cultivar Shimai 22), the photosynthetic parameters (chlorophyll content and Pn and gs), proline and soluble sugar contents, plant biomass, and the yield traits (grain number per spike, 1000 grain weight, and yield) were alleviated to different degrees. In contrast, the plant nitrogen content, population stem numbers, and spike amounts per planting unit area were shown to be superior to the control. According to the physiological parameters, population plant growth traits, yield and protein yield, the tested strong-gluten wheat cultivars were ranked in an order of Gaoyou 5218, Shiyou 20, and Shiluan 02-1, with the first one displaying the best on behaviors of photosynthetic parameters, osmotic regulation substance content and yield and to be similar to those shown in the control cultivar. Moreover, the grain protein yield of Gaoyou 5218 plants was higher than that of the control. Regression analysis showed that the expression level of <SUP>Δ</SUP>1-pyrrolin-5-carboxylate synthase (P5CS) gene <i>TaP5CS1</i> was highly positively correlated with the proline content of the tested varieties during growth stages, and the transcript abundance of nitrate transporter gene <i>TaNRT2.1</i> was significantly positively correlated with the nitrogen accumulative amount of plants during the same growth period. These results indicated that above genes played an important role in regulating the osmotic regulation ability and nitrogen uptake and accumulation of the strong-gluten and control cultivars under water-saving cultivation conditions. Gaoyou 5218 showed relatively elite yield and protein yield per unit area, indicating that this cultivar has an important application prospective for strong-gluten wheat cultivation.

Effects of semi-deep water irrigation on hybrid indica rice lodging resistance.

Recently, rice-aquatic animal integrated farming (RAAIF) has grown rapidly in China due to its favorable benefits and the lower application of pesticides and fertilizers. However, rice lodging occurs frequently under RAAIF, which restricts rice yield. We assumed that semi-deep water irrigation may cause weaker rice-lodging resistance since it is the most significant environmental factor for RAAIF that distinguishes it from rice monoculture. To investigate the response of rice stem lodging resistance to semi-deep water irrigation and its mechanism, three irrigation management modes, namely the typical high-yield irrigation model that is mainly based on swallow and wetting (CK), semi-deep water irrigation from the late tillering stage to the jointing stage (SDI1), and semi-deep water irrigation from the jointing stage to the middle grain-filling stage (SDI2), were conducted using three hybrid indica rice varieties: Shenliangyou136 (SLY136), Huiliangyousimiao (HLYSM), and Wanxiangyou982 (WXY982). Mechanics analysis indicated that the bending moment by the whole plant (WP) and the breaking strength (M) were both decreased by semi-deep water irrigation when compared with CK, while M presented a larger decreasing amplitude than WP, which induced the increased lodging index (LI) of rice, for all the tested varieties. SLY136 and HLYSM were affected more strongly by SDI1, whereas WXY982 was affected more strongly by SDI2. Significant weaker breaking force under two semi-deep water irrigation modes contributed to the decreased M relative to CK. Morphology results showed that semi-deep water irrigation reduced the thickness of mechanical tissues, sclerenchyma cells, and parenchyma cells; reduced the number of vascular bundles; and caused a looser arrangement, inducing the lower fullness of the rice basal internode. Decreased accumulation of lignin and cellulose was also linked to the weaker breaking force of the basal internode under semi-deep water irrigation, which was verified by correlation analysis. WXY982 had obvious lower structural carbohydrates content under semi-deep water irrigation than the other two varieties and thus showed worse breaking force and LI. In conclusion, the worse mechanical strength of the rice basal internode under semi-deep water irrigation was closely associated with weaker vascular bundle development and suppressed structural carbohydrate accumulation, and the decreasing degree of lodging resistance varied between rice varieties and semi-deep water irrigation periods.

Simulation of daily maize evapotranspiration at different growth stages using four machine learning models in semi-humid regions of northwest China

The accurate estimation of crop evapotranspiration (ETc) is essential for precision irrigation, optimal allocation of regional water resources, and efficiency improvement of agricultural water resources. This study developed Random Forest (RF), Support Vector Machine (SVM), Artificial Neural Network (ANN) and Extreme Learning Machine (ELM) models for maize ETc estimation in northwest China. The meteorological data and crop data from 2011 to 2012 were used to train the RF, SVM, ANN and ELM. The models’ simulation accuracy was verified by using the data of 2013 under six different input combinations. The input combinations included daily data for crop coefficient (Kc), global solar radiation (Rs), wind speed (u2), maximum and minimum air temperatures (Tmax and Tmin), and maximum and minimum relative humidity (RHmax and RHmin). The results showed that the SVM model achieved the highest simulation accuracy at the seedling emergence to jointing stage and at the grouting to harvest stage of summer maize, with the coefficient of determination (R2) ranging 0.701–0.895 and 0.637–0.841, mean absolute error (MAE) ranging 0.310–0.654 and 0.468–0.743 mm/d, and mean square error (MSE) ranging 0.227–0.722 and 0.513–1.227 mm/d, respectively. The ELM model achieved the highest simulation accuracy at the booting to silking stage and during the whole growth period, the coefficient of determination (R2) ranging 0.601–0.828 and 0.891–0.954, mean absolute error (MAE) ranging 0.418–1.194 and 0.285–0.530 mm/d, and mean square error (MSE) ranging 0.887–2.515 and 0.182–0.587 mm/d, respectively. Considering the accessibility and simulation accuracy of input parameters, the SVMⅠ-2, ELMⅡ-5, SVMIII-4, and ELMIV-2 models were recommended for simulating ETc at the seedling emergence to jointing stage, at the booting to silking stage, at the grouting to harvest stage, and during the whole growth period, with the coefficient of determination (R2) of 0.796, 0.879, 0.800 and 0.896, mean absolute error (MAE) of 0.416, 0.418, 0.553 and 0.328 mm/d, and mean square error (MSE) of 0.327, 0.887, 0.655 and 0.190 mm/d, respectively. In conclusion, machine learning models can accurately simulate the daily evapotranspiration of maize in northwest China.

Cross-scenario automatic sleep stage classification using transfer learning and single-channel EEG

Sleep staging via manual inspection is time-consuming and inefficient, and as such, automatic sleep stage classification methods have been proposed and successfully implemented. However, these conventional supervised learning models are not suitable for cross-scenario sleep staging tasks due to the shift data distribution problem. This study aims to explore the use of transfer learning to transfer knowledge from a labeled source dataset to a new target domain where labels are difficult to obtain, so as to help solve the classification problem in a new domain in practical sleep staging scenarios. A novel end-to-end deep learning network that includes a feature extractor, a sleep stage classifier, and a domain adaptation network was proposed. The proposed domain adaptation network can accomplish distribution alignment between source and target domains, through the application of both joint distribution loss and stage transition loss. Cross-channel, cross-subject and channel, and cross-dataset experiments were designed to verify the feasibility of the proposed network using three publicly available datasets. The results indicate an average accuracy improvement ranging from 0.1% to 6.1% (average of 2.9%), a macro-averaging F1-score improvement ranging from 0.1% to 5.1% (average of 2.6%), and a Cohen’s kappa coefficient improvement ranging from 0.016 to 0.083 (average of 0.045) after using transfer learning, when compared with a non-transfer model. Relative to similar existing transfer learning methods for sleep staging, the proposed method was implemented in an unsupervised manner and achieved success in cross-scenario sleep staging tasks, which is more suitable for practical applications in daily life.

Coated diammonium phosphate combined with Paecilomyces variotii extracts improves root architecture, enhances spring low temperature tolerance, and increases wheat yield

The growth, development, and grain yield of winter wheat (Triticum aestivum L.) was seriously limited by the low use efficiency of phosphorus (P) fertilizers and the spring low-temperature events. Diammonium phosphate is one of the most important sources of P fertilizers worldwide. Controlled release diammonium phosphate (CRDAP) synchronizes fertilizers P release and crop growth demand is positive to improve P use efficiency (PUE) and reduce P loss, whereas biostimulants such as Paecilomyces variotii extracts (ZNC) have ultrahigh activity in promoting crop growth and abiotic stress resistance. However, little information is available on synergistic effects of CRDAP and ZNC on winter wheat growth. A three-year field experiment from October 2017 to June 2020 was conducted with five treatments: DAP (application of conventional diammonium phosphate); CDAP (CRDAP application); DAPZ (application of diammonium phosphate–ZNC composite); CDAPZ (application of CRDAP–ZNC composite); Control (no P fertilizer or ZNC). Plant growth (root, shoot, and photosynthesis), hormone (auxin content from roots and leaves, and ABA content from leaves), ROS scavenging system (H2O2, superoxide dismutase (SOD), peroxidase (POD), catalase (CAT), and glutathione reductase (GR)), and soil available P were measured along with yield and PUE. The results showed that the yield and PUE of CDAPZ were significantly more (by 6.0% and 9.3 percentage points, respectively) than for CDAP. The interactive effects between CRDAP and ZNC were evidenced by the CDAPZ enhanced soil available-P supply and increased average available-P content (22.0% more than CDAP in the 0–40 cm soil layer) and improved root growth with 29.9% increase in total root length by CDAPZ than CDAP at the jointing stage. Moreover, the IAA content of roots from CDAPZ was higher than any other treatments, and the effect of ZNC on IAA content was verified by a laboratory incubation experiment. Similarly, the highest photosynthetic rate was found in CDAPZ, which was 11.0–17.0% higher than that in CDAP. The application of CRDAP combined with ZNC decreased H2O2 content by 8.6%, and increased the activities of SOD, POD, CAT, and GR, thereby enhancing the cold tolerance of wheat. Hence, CRDAP–ZNC composite may serve as an emerging green fertilizer technology and play a crucial role in improving crops response to climate change, and increasing crop yield and PUE.

Deciphering soil amendments and actinomycetes for remediation of cadmium (Cd) contaminated farmland

Soil heavy metal pollution is one of the most serious environmental problems in China, especially cadmium (Cd), which has the most extensive contaminated soil coverage. Therefore, more economical and efficient remediation methods and measures are needed to control soil Cd contamination. In this study, different amendments (biochar (B), organic fertilizer (F), lime (L)) and actinomycetes (A) inoculants were applied to Cd contaminated farmland to explore their effects on wheat growth. Compared with Control, all treatments except A treatment were able to significantly increase the underground parts dry mass of wheat, with the highest increase of 57.19 %. The results showed that the B treatment significantly increased the plant height of wheat by 3.45 %. All treatments increased wheat SOD activity and chlorophyll content and reduced the MDA, which contributes to wheat stress resistance under Cd contamination. F, L and AF treatments can significantly reduce the Cd content in wheat above- and underground parts by up to 56.39 %. Soil amendments can modify the physical and chemical properties of the soil, which in turn affects the absorption of Cd by wheat. Moreover, the addition of soil amendments significantly affects the composition and structure of the rhizospheric soil bacterial community at the wheat jointing stage. The application of organic fertilizer increases the richness and diversity of the bacterial community, while lime makes it significantly decreases it. T-test and microbiome co-occurrence networks show that actinomycetes could not only effectively colonize in local soil, but also effectively enhance the complexity and stability of the rhizosphere microbial community. Considering the practical impact of different treatments on wheat, soil microorganisms, economic benefits and restoration of soil Cd contamination, the application of organic fertilizer and actinomycetes in Cd contaminated soil is a more ideal remediation strategy. This conclusion can be further verified by studying larger repair regions and longer consecutive repair cycles to gain insight into the repair mechanism.

Optimization of sowing date and irrigation schedule of maize in different cropping systems by APSIM for realizing grain mechanical harvesting in the North China Plain

Grain mechanical harvesting can decrease the harvest cost and improve the efficiency of maize production. However, the optimization of the sowing date and irrigation schedule of maize in existing studies rarely considered the grain mechanical harvesting. Therefore, the sowing date and irrigation schedule of two maize cultivars in three cropping systems was optimized by considering yield, water use efficiency (WUE), and grain mechanical harvesting. The quality of grain mechanical harvesting is mainly influenced by grain moisture content. Thus, Agricultural Production Systems sIMulator (APSIM) was coupled with a grain dry down model to simulate maize production in the northern part of the North China Plain (NCP). The latest date for grain mechanical harvesting of maize was analyzed using the date when the grain moisture content decreased to 25% for the first time (DCM25). The DCM25, yield, WUE, and irrigation amount were used as constraints in the optimization. The results showed that, the optimal sowing dates under full irrigation of spring maize in SM (monocropping maize system), spring maize and summer maize in WMM (winter wheat-summer maize-spring maize system) for Huanong887 were from 6th May to 10th June, from 6th May to 16th May and 10th June, respectively. The optimal sowing dates of spring maize in SM were from 1st May to 5th June for Zhengdan958. The summer maize in DWM (winter wheat-summer maize double cropping system) could not achieve high-quality grain mechanical harvesting when using Huanong887 and Zhengdan958. In different hydrological year types, the optimal irrigation schedule with grain mechanical harvesting involved irrigation (80 mm each time) 1–3 times during sowing, jointing and flowering stages of spring maize in SM and summer maize in WMM. For spring maize in WMM, the optimal irrigation schedule involved irrigation 2–3 times during sowing, jointing, and flowering stages. The optimization method could provide a reference for other sites to promote high-efficient maize production.

Effects of Planting Density on Root Spatial and Temporal Distribution and Yield of Winter Wheat

The root system is the only vital organ for plants to connect with soil moisture and nutrients and obtain feedback information. This research aimed to explore the response of different spike type winter wheat varieties to plant and row spacing configurations. Multi-spike and large-spike winter wheat varieties were used as materials. By setting different plant row configurations and planting densities, the spatial and temporal distribution of root length density, root diameter, root dry weight density, and the main control factors of root growth and development of winter wheat during the whole growth period were studied. The results showed that the root system was the most widely distributed and the root diameter was the largest in the 0–40 cm soil depth, with an average root system diameter of more than 0.5 mm. The root length density and root diameter peaked at the heading stage, decreased at the maturity stage, and the root dry weight density peaked at the jointing stage. The jointing stage and heading stage are the most vigorous periods of root growth in winter wheat, when the center of gravity of root growth in winter wheat is gradually moving down. Therefore, the rapid growth and elongation time of a root system can be effectively prolonged at the jointing stage and heading stage, and the root growth rate can be improved. Promoting root thickening can effectively meet the needs for water and nutrients, for the formation and filling of aboveground plants and grains, in the later stage, which is conducive to the formation of aboveground dry matter production and final yield. The root distribution was greatest in the 0–60 cm soil depth, accounting for 95.13–97.84% of the total root length. After the heading stage occurs, the upper roots begin to decline in large quantities. Thus, the jointing stage and heading stage require fertilization and other farmland management operations to increase root nutrients for the ground parts and dry matter accumulation to provide sufficient nutrients so that the number of effective panicles, grain weight, and the number of spike grains coordinate to achieve the highest grain yield. Results showed that the highest yield can be achieved with the planting pattern X2M1. A comprehensive analysis showed that the genetic characteristics of winter wheat varieties were different, and there were some differences in the correlation between wheat yield and root system at the different growth stages. The correlation between the root parameters and yield of multi-spike winter wheat during the overwintering-jointing stage was obvious. For large-spike type winter wheat in the jointing stage, the yield correlation is most obvious.

Adaptabilities of Water Production Function Models for Rice in Cold and Black Soil Region of China

Crop water production function models (WPFMs) are required methods to study the relationships between yield and water consumption under regulated deficit irrigation (RDI). In this study, a pot experiment was established to study the effect of water deficit during both individual growth stages and across two consecutive growth stages of rice on yield, water consumption, and water use efficiency (WUE) in 2017 and 2018. Light, medium, and severe water deficits were set as 80~90%, 70~80%, and 60~70% of saturated soil moisture content, respectively. The accuracies of five WPFMs were tested based on the experimental results. The results showed that yields and WUE of a light water deficit were higher than those of medium and severe water deficits at each growth stage. The yields and WUE of light drought stress treatments in the flowering and milky stages were higher than the saturated soil moisture control by 4~7.4% and 5.3~20.6%, respectively. Water consumption decreased with increasing water deficit across two consecutive growth stages. The Minhas model had the highest simulation accuracy of the five WPFMs, with relatively lower AE, RMSE, Cv, CRM, and higher R2, which were 0.0002, 0.0634, 6.9965, 0.0002, and 0.9951 in 2017 and 0.0110, 0.0760, 8.9882, 0.0131, and 0.9923 in 2018, respectively. The sensitivity indices for the Minhas model more accurately reflected the sensitivity of rice yield to water deficit at different growth stages in 2017 and 2018, compared with the Jensen model, Stewart model, Blank model, and Singh model. Rice yield was most sensitive to water deficit at the jointing and booting stage. The results indicate that the Minhas model is the most suitable WPFM for guiding rice irrigation practices in cold and black soil regions of China.

Wheat TaSnRK2.10 phosphorylates TaERD15 and TaENO1 and confers drought tolerance when overexpressed in rice.

Wheat (Triticum aestivum) is particularly susceptible to water deficit at the jointing stage of its development. Sucrose non-fermenting 1-related protein kinase 2 (SnRK2) acts as a signaling hub in the response to drought stress, but whether SnRK2 helps plants cope with water deficit via other mechanisms is largely unknown. Here, we cloned and characterized TaSnRK2.10, which was induced by multiple abiotic stresses and phytohormones. Ectopic expression of TaSnRK2.10 in rice (Oryza sativa) conferred drought tolerance, manifested by multiple improved physiological indices, including increased water content, cell membrane stability, and survival rates, as well as decreased water loss and accumulation of H2O2 and malonaldehyde. TaSnRK2.10 interacted with and phosphorylated early responsive to dehydration 15 (TaERD15) and enolase 1 (TaENO1) in vivo and in vitro. TaERD15 phosphorylated by TaSnRK2.10 was prone to degradation by the 26S proteasome, thereby mitigating its negative effects on drought tolerance. Phosphorylation of TaENO1 by TaSnRK2.10 may account for the substantially increased levels of phosphoenolpyruvate (PEP), a key metabolite of primary and secondary metabolism, in TaSnRK2.10-overexpressing rice, thereby enhancing its viability under drought stress. Our results demonstrate that TaSnRK2.10 not only regulated stomatal aperture and the expression of drought-responsive genes, but also enhanced PEP supply and promoted the degradation of TaERD15, all of which enhanced drought tolerance.

Response of root endosphere bacterial communities of typical rice cultivars to nitrogen fertilizer reduction at the jointing stage.

Root endosphere bacterial communities play an essential role in regulating plant growth and resisting nutrient stress. However, there is still a lack of knowledge on the response of root endosphere bacterial communities of rice (Oryza sativa L.) to reduced nitrogen (N). We investigated endosphere bacterial communities and quantified the abundance of functional genes involved in N conversion and ethylene synthesis in the roots of hybrid rice and japonica rice at the jointing stage under the traditional high-yielding N fertilization (THYN) and reduced N fertilization (RN). Results showed different selection preferences of root endosphere bacterial communities of two rice cultivars under THYN treatment. Specifically, δ-proteobacteria and Firmicutes were enriched in the root endosphere of hybrid rice, while γ-proteobacteria and α-proteobacteria were enriched in the root endosphere of japonica rice. Root endosphere bacterial communities of two rice cultivars showed different tolerance to RN, but showed commonalities in the selection of bacteria taxon, such as the massive enrichment of Burkholderia-Caballeronia-Paraburkholderia in the root endosphere. Additionally, the relative abundances of nifH, amoA-archaea, nirS, nirK, and acdS genes in japonica rice roots were higher than those in roots of hybrid rice under THYN treatment. RN significantly increased the relative abundance of acdS gene in roots of hybrid rice, alleviating the decline in above-ground dry matter weight. Our study revealed potential microbiological strategies for rice to cope with insufficient N supply.

Analysis of Gaps Yield and Resource use Efficiency of Cold-Region Japonica Rice

Rice is the primary staple food for more than 50% of the world’s population. Narrowing the gap between the maximum potential food crop yield and actual yield is critical for improving the current yield, resource use efficiency, and global food security. Here, we examined the fertilizer use efficiency (FUE), radiation use efficiency (RUE), and temperature production efficiency (TPE) of four management treatments (super high yield [SH], high yield and high efficiency [HH], farmer level [FP], and basic production level [CK]). SH and HH treatments significantly reduced the yield gap by 22.4 and 9.5%, respectively. The large yield gap between HH and FP was mainly attributed to high specific leaf weight at the jointing stage (7.5–7.7 mg·cm−2), and the high leaf area maintained during tillering–jointing stages (35.4–37.6 m2·m−2·per day). Compared with FP, HH increased the specific leaf weight in the heading stage (8.2–8.4 mg·cm−2), relative crop growth rate, net assimilation rate (NAR), and mean leaf area index (> 2.6). Moreover, compared with FP, HH significantly increased partial factor productivity (PFP) of nitrogen, FUE, TPE, and RUE owing to greater yield and NAR after the full heading stage. Although the HH yield was 93.32% that of SH, HH increased PFP of fertilizer (12.5%), fertilizer nitrogen (9.07%), and fertilizer K2O (36.34%), and required 26% less fertilizer than SH. The findings of this study could facilitate high-efficiency rice production and bridging of yield gaps.

Straw incorporation interacting with earthworms mitigates N2O emissions from upland soil in a rice-wheat rotation system

Intensive attentions have been paid to the positive effects on nitrous oxide (N2O) production under straw return or the presence of earthworms. Straw return as a sustainable practice can promote earthworm growth, how the interactions between straw and earthworms affect N2O production is still not well known. A split-plot field experiment (straw return as main plot and earthworm addition as subplot) was performed to quantify the interactive effects of straw and earthworm on N2O emissions from a wheat field and to determine the underlying mechanisms from nitrification and denitrification processes. The results showed that straw return significantly increased N2O emissions by 41.0 % under no earthworm addition but decreased it by 19.0 % under earthworm addition compared with straw removal (P < 0.05). The significant interaction between straw and earthworm benefits the mitigation of N2O emissions. Random forest model showed that denitrification and nitrification were dominant processes to affect N2O emissions at the jointing and booting growth stages of wheat, respectively. The interaction between straw and earthworm significantly decreased the abundances of N2O-producing bacterial genes such as nirS and nirK at the jointing stages, and AOB at the booting stages. The contrasting mechanisms in regulating N2O emissions at different growth stages should be considered in nitrogen recycling models to accurately predict available N and N2O dynamics. Our findings suggest that N2O emissions under straw return can be weakened with the increasing earthworm populations under the scenario of widely used conservation practices (e.g., straw return and no-till) due to significant interaction between straw and earthworms.

Planting models and deficit irrigation strategies to improve radiation use efficiency, dry matter translocation and winter wheat productivity under semi-arid regions

The dry-land farming system of China relies on plastic film mulching and natural rainfall to mitigate damage caused by drought. However, the applications of deficit irrigation modes combined with the planting models can significantly increase production of wheat, dry matter translocation and radiation use efficiency (RUE) remains unidentified. Thus, in 2016–2018, we conducted field trials that implemented four deficit irrigation modes (IJF: irrigation at jointing and flowering stages; IF: irrigation at flowering stage; IJ: irrigation at jointing stage; NI: no irrigation) under two cultivation patterns (ridge furrow rainfall harvesting system (RF); traditional flat cultivation (TF)). The results indicated that the effects of RF system with deficit irrigation (IJF: 250 mm) could significantly increase the soil moisture, and thus enhanced LAI, In value, IPAR, RUE, and PAR capture ratio than that of TF-NI planting. This is due to decreased canopy light transmittance (LT), reflection and penetration ratio of PAR, as a result considerable improve the biomass translocation and grain yield. Owing to the very low soil water content after the seed-filling, the LAI, IPAR, and In value decreased during the seed-filling under water stress, ultimately affecting the dry matter translocation efficiency. While the IJF and IF treatments provided water for reproductive growth stage, therefore, the production of wheat and RUE were significantly maximum compared with IJ and NI irrigation mode. Under the RF system with IJF, IF, and IJ treatments the grain yield increased by 81.2%, 56.8%, 45.6% and 17.2%, then that of TF-NI treatment, respectively. The highest RUE (1.93 g MJ−1), dry-matter translocation (154.2%) and seed yield (81.2%) were obtained in the RF-IJF treatment compared with TF-NI. Therefore, the RF-IJF treatment significantly improved the earlier development and rapid plant growth, which is a suitable planting model for increasing soil moisture, LAI, RUE, DMT, and winter wheat production.

Nitrogenous Fertilizer Levels Affect the Physicochemical Properties of Sorghum Starch.

Nitrogen is a key factor affecting sorghum growth and grain quality. This experiment was designed to investigate the physicochemical properties of sorghum starch in four sorghum varieties (Liaoza 10, Liaoza 19, Jinza 31, and Jinza 34) under four nitrogen levels: 0 kg/ha urea (N1), 300 kg/ha urea as base fertilizer (N2), 300 kg/ha urea as topdressing at the jointing stage (N3), and 450 kg/ha urea as topdressing at the jointing stage (N4). The results showed that grain size and amylose content increased with increasing nitrogen fertilizer level, peaking at N3. The peak viscosity, final viscosity, gelatinization temperature, initial temperature, final temperature, and enthalpy value increased with the nitrogenous fertilizer level, peaking at N3. The application of nitrogen fertilizer at the jointing period significantly increased the above indicators. However, excess nitrogen at the jointing period (N4) can significantly reduce the above indicators, thus changing the physicochemical properties and structure of sorghum starch. Overall, nitrogen significantly affects the structure and physicochemical properties of sorghum starch.

Shading decreases lodging resistance of wheat under different planting densities by altering lignin monomer composition of stems.

To clarify the influences of shading stress and planting density on the lignin monomer composition of wheat stems and their relationship with lodging resistance, Lodging resistant variety Shannong 23 (SN23) and lodging sensitive variety Shannong 16 (SN16) were grown during 2018-2019 and 2019-2020 growing seasons. The planting densities were 150 × 104 plants ha-1 (D1), 225 × 104 plants ha-1 (D2) and 300 × 104 plants ha-1 (D3). At the jointing stage, an artificial shading shed was used to simulate shading stress. Then the effects of shading on stem morphological characteristics, lignin monomer composition and lodging resistance of wheat under different planting densities were studied. Results indicate that shading at the jointing stage increased the length of basal internodes and the plant height and moved the height of center of gravity (CG) upward. Moreover, the stem diameter and the wall thickness decreased by 0.10-0.53 mm and 0.18-0.40 mm, respectively. The stem filling degree was reduced accordingly. As indicated by the correlation analysis and the stepwise regression analysis, shading-induced lodging mainly resulted from changes in the stem morphological characteristics and lignin accumulation. The influential magnitude of these factors was ordered as follows: stem filling degree, wall thickness, lignin content, contents and proportions of monomers S and H, and length of the second internode. The expression abundance of TaPAL, TaCOMT, TaCCR, and TaCAD declined in response to shading stress and high planting density. As a result, the distribution ratios of photosynthetic carbon sources to lignin monomers S, G and H were changed. The lignin content of stems on the day 42 after the jointing stage decreased by 18.48%. The monomer S content decreased, while the content and proportion of monomer H increased, thus weakening the breaking strength of wheat stems.

Nitrogen fertilizer application rates and ratios promote the biochemical and physiological attributes of winter wheat.

Improper optimization of the rates and ratios of nitrogen application reduces grain yields and increases the nitrogen loss, thereby affecting environmental quality. In addition, scarcer evidence exists on the integrative approach of nitrogen, which could have effects on the biochemical and physiological characteristics of wheat. Treatments were arranged as nitrogen (N) rates of 00, 75, 150, 225, and 300 kg ha-1 in the main plots, and different nitrogen ratios were organized in subplots at 5:5:0:0 and 6:4:0:0, which were applied at the sowing, jointing, flowering, and grain filling stages. The results revealed that 225 kg N ha-1 significantly enhanced the stomatal conductance (G s), photosynthetic rate (P n), intercellular CO2 (C i), transpiration rate (T r), and total chlorophyll by 28.5%, 42.3%, 10.0%, 15.2%, and 50%, receptively, at the jointing stage in comparison to the control (0 kg N ha-1). Nitrogen application of 225 kg ha-1 increased the soil-plant analysis development (SPAD) value and the chlorophyll a, chlorophyll b, and carotenoid contents of winter wheat under the 6:4:0:0 ratio. The trend of the photosynthetic characteristics was observed to be greater at the 6:4:0:0 fertilization ratio compared to that at 5:5:0:0. The photosynthetic rate was significantly associated with the biochemical and physiological characteristics of winter wheat. In conclusion, the nitrogen dose of 225 kg ha-1 and the ratio of 6:4:0:0 (quantity applied at the sowing, jointing, flowering, and grain filling stages) effectively promoted the photosynthetic and other physiological characteristics of winter wheat.

Stable isotopes δ18O and δ2H reveal differential water uptake from intercropped maize and soybean soil profiles

The objective of this study was to investigate the effect of different intercropping modes on grain yield, crop water uptake, and water use efficiency in the rainfed agricultural regions. Conventional research methods had difficulties in accurately measuring water absorption soil profiles of grain crops under intercropping system. In this study, the seasonal variations in water uptake patterns of maize and soybean were identified using stable isotopes δ 18 O and δ 2 H in plant and soil water coupled with IsoSource model in monocrop and three intercropping modes: M2S2 (2 rows of maize and 2 rows of soybean), M2S4 (2 rows of maize and 4 rows of soybean), and M4S2 (4 rows of maize and 2 rows of soybean) on the Loess Plateau, China. The dominant water uptake depth of maize under monocrop contributed to 61.8 ± 10.3% in 0–20 cm, 40.3 ± 3.4% in 150–200 cm, and 65.3 ± 11.6% in 20–70 cm soil profiles of the total water uptake at the jointing, silking, and maturity stages, respectively. The dominant water uptake depth of intercropped maize contribute to 46.1 ± 1.1% in 0–20 cm, 31.8 ± 0.8% in 70–150 cm, and 36.9 ± 2.1% in 150–200 cm soil profiles of the total water uptake at the jointing, silking, and maturity stages, respectively. For soybean, the soil water at the 0–20 cm depth contributed 73.0 ± 2.4% (monocrop) and 78.4 ± 6.2% (intercrops) of the total water uptake across all three growth stages, respectively. Land equivalent ratio greater than one indicates yield advantages in intercropping systems compared to monocrop. Intercropped maize absorbed water from the soil layer deeper than that of soybean during the middle to late growth stages, indicating the intercropping advantages due to the differential water absorption depth. M4S2 mode had shallower main water absorption depth and higher water use efficiency than M2S2 and M2S4, respectively. The present study identified differential water absorption patterns between maize and soybean. The M4S2 intercrop mode was considered the optimal mode for rainfed intercropping systems due to its greater land and water use efficiency on the Loess Plateau. • Stable isotopes δ 18 O and δ 2 H reveal root-zone water dynamics in intercropping. • The soybean mainly used soil water from 0 to 20 cm under all cropping modes. • Maize had deeper main water absorption than soybean when intercropped. • The water absorption depth of maize increased over the growth period in intercropping.

Delayed irrigation at the jointing stage increased the post-flowering dry matter accumulation and water productivity of winter wheat under wide-precision planting pattern.

The North China Plain (NCP) faces a severe water shortage, and the amount of rainfall cannot guarantee the growth and development of winter wheat. Therefore, it is important to explore a suitable irrigation and planting pattern to solve the problem of water shortage in this region. A 4-year experiment was carried out in the NCP during 2015-2019. The main plots included two planting patterns: a wide-precision planting pattern (W) and a conventional planting pattern. Two irrigation regimes were established for each planting pattern: 60-mm irrigation at the jointing stage (I1) and 60-mm irrigation delayed 10 days at the jointing stage (I2). The soil water consumption, dry matter translocation, grain yield and crop water productivity were investigated. The results showed that WI2 treatment obtained the highest grain yield and crop water productivity. The wide-precision planting pattern could significantly decrease soil water consumption; however, delayed irrigation effectively reduced soil water consumption only in normal rainfall years. The coupling of delayed irrigation at the jointing stage and a wide-precision planting pattern significantly enhanced dry matter accumulation after flowering and the contribution of dry matter accumulation after flowering to grain yield during the growing seasons. WI2 could decrease the evapotranspiration and improve the grain yield, thus increasing crop water productivity. The combination of a wide-precision planting pattern and delayed irrigation at the jointing stage was the appropriate agronomic practice for efficient grain yield and crop water productivity in the North China Plain. © 2022 Society of Chemical Industry.

The Integration of Metabolomics and Transcriptomics Provides New Insights for the Identification of Genes Key to Auxin Synthesis at Different Growth Stages of Maize.

As a staple food crop, maize is widely cultivated worldwide. Sex differentiation and kernel development are regulated by auxin, but the mechanism regulating its synthesis remains unclear. This study explored the influence of the growth stage of maize on the secondary metabolite accumulation and gene expression associated with auxin synthesis. Transcriptomics and metabonomics were used to investigate the changes in secondary metabolite accumulation and gene expression in maize leaves at the jointing, tasseling, and pollen-release stages of plant growth. In total, 1221 differentially accumulated metabolites (DAMs) and 4843 differentially expressed genes (DEGs) were screened. KEGG pathway enrichment analyses of the DEGs and DAMs revealed that plant hormone signal transduction, tryptophan metabolism, and phenylpropanoid biosynthesis were highly enriched. We summarized the key genes and regulatory effects of the tryptophan-dependent auxin biosynthesis pathways, giving new insights into this type of biosynthesis. Potential MSTRG.11063 and MSTRG.35270 and MSTRG.21978 genes in auxin synthesis pathways were obtained. A weighted gene co-expression network analysis identified five candidate genes, namely TSB (Zm00001d046676 and Zm00001d049610), IGS (Zm00001d020008), AUX2 (Zm00001d006283), TAR (Zm00001d039691), and YUC (Zm00001d025005 and Zm00001d008255), which were important in the biosynthesis of both tryptophan and auxin. This study provides new insights for understanding the regulatory mechanism of auxin synthesis in maize.