[Effects of seed grading on population regularity degree and yield of summer maize].

Grading seeds based on grain size is an effective measure to improve population regularity degree and increase the yield of summer maize. Taking Denghai 605 as the experimental material, we set up a field experiment with treatments based on grain size: large seeds (L), medium-round seeds (MR), medium-flat seeds (MF), medium-round and medium-flat mixed seeds (MRF), and small seeds (S), with no-grading seeds as control (CK). We investigated seedling emergence rate, population regularity degree (including height, ear height and stem diameter), seedling sturdiness index, photosynthetic characteristics, dry matter accumulation and distribution characteristics, and yield.

Differences of cadmium uptake and accumulation in roots of two maize varieties (Zea mays L.).

Different maize varieties respond differentially to cadmium (Cd) stress. As the first organ in contact with the soil, the response of the root is particularly important. However, the physiological mechanisms that determine the response are not well defined.

Maize (Zea mays L.) responses to salt stress in terms of root anatomy, respiration and antioxidative enzyme activity.

Background: Soil salt stress is a problem in the world, which turns into one of the main limiting factors hindering maize production. Salinity significantly affects root physiological processes in maize plants. There are few studies, however, that analyses the response of maize to salt stress in terms of the development of root anatomy and respiration.

Long-term integrated soil-crop management improves soil microbial community structure to reduce GHG emission and increase yield.

Integrated soil-crop management (ISCM) has been shown as an effective strategy to increase efficiency and yield while its soil microbial community structure and function remain unclear. We evaluated changes in soil physicochemical factors, bacterial community structure responses, and the contributions of soil properties and bacterial communities to summer maize-winter wheat yield and GHG emissions through an ISCM experiment [T1 (local smallholder farmers practice system), T2 (improved management system), T3 (high-yield production system), and T4 (optimized management system)], which could provide scientific guidance for sustainable development of soil in summer maize-winter wheat rotation system. The results showed that the optimized ISCM could improve the soil quality, which significantly changed the soil bacterial community structure to reduce GHG emissions and increase yield.

Effects of hydrogen peroxide priming on yield, photosynthetic capacity and chlorophyll fluorescence of waterlogged summer maize.

Extreme rainfall events during the summer maize growth and development periods, which have induced losses in summer maize production. There was a completely randomized block experiment being designed with four treatments: waterlogging for 6 days at the V3 stage (C-W), HO-priming + non-waterlogging (H-CK), HO-priming + waterlogging for 6 days at the V3 stage (H-W) and control (C-CK). This study investigated the effects of HO priming on yield and photosynthetic parameters of (.

Yield of summer maize hybrids with different growth duration determined by light and temperature resource use efficiency from silking to physiological maturity stage.

In order to explore the physiological mechanism of different yield of summer maize ( L.) hybrids with different growth duration, a field experiment was conducted to study the growth stage, leaf photosynthetic characteristics, dry matter accumulation (DMA), transport and distribution characteristics and yield of the early maturity hybrid Denghai 518 (DH518) and the mid-late maturity hybrid Denghai 605 (DH605) from 2017 to 2021. The results showed that the yield of DH605 was significantly higher than that of DH518.

Influences of split application and nitrification inhibitor on nitrogen losses, grain yield, and net income for summer maize production.

The application of nitrogen (N) fertilizer combined with nitrification inhibitor is considered to be one of the effective strategies to improve N efficiency and reduce N loss. While the chemical and physical properties of nitrapyrin (CP) in fertilizers have been evaluated to increase N efficiency, a lack of comprehensive evaluation of the effects of adding CP on summer maize yield, environmental benefits and economic income under different fertilization methods. In this study, two fertilization methods were used: split-N application and one-time basal N fertilizer before sowing.

Spraying Ethephon Effectively Increased Canopy Light Transmittance of Densely Planted Summer Maize, Thus Achieving Synergistic Improvement in Stalk Lodging Resistance and Grain Yield.

Increasing planting density is an effective way to improve maize yield, but high plant populations often cause a lodging problem. This experiment was conducted to investigate the effect of increasing planting density on stalk lodging resistance and grain yield, and to explore the effects on stalk and yield properties of spraying ethephon in densely planted summer maize. The summer maize hybrid, Xundan20 (XD20), was used as experimental material.

Nitrapyrin Mitigates Nitrous Oxide Emissions, and Improves Maize Yield and Nitrogen Efficiency under Waterlogged Field.

In order to explore the effects of nitrapyrin (N-Serve) application on greenhouse gas emission and nitrogen (N) leaching of a waterlogged maize ( L.) field, we investigated the effects of applying nitrapyrin on soil ammonium (NH-N) and nitrate nitrogen (NO-N) content, nitrous oxide (NO) fluxes, and the warming potential (GWP) in a waterlogged maize field. The design included three treatments: waterlogging treatment with only urea application (V-3WL), waterlogging treatment with urea and nitrapyrin application (V-3WL+N), and no waterlogging treatment applying only urea (CK).

Exogenous 6-Benzyladenine Improved the Ear Differentiation of Waterlogged Summer Maize by Regulating the Metabolism of Hormone and Sugar.

Waterlogging (W-B) is a major abiotic stress during the growth cycle of maize production in Huang-huai-hai plain of China, threatening food security. A wide range of studies suggests that the application of 6-benzyladenine (6-BA) can mitigate the W-B effects on crops. However, the mechanisms underlying this process remain unclear.

6-Benzyladenine increasing subsequent waterlogging-induced waterlogging tolerance of summer maize by increasing hormone signal transduction.

Summer maize is frequently subjected to waterlogging damage because of increased and variable rainfall during the growing season. The application of 6-benzyladenine (6-BA) can effectively mitigate the waterlogging effects on plant growth and increase the grain yield of waterlogged summer maize. However, the mechanisms underlying this process and the involvement of 6-BA in relevant signal transduction pathways remain unclear.

[Effects of spraying desiccant on dehydration characteristics and grain quality of summer maize hybrids differing in maturity].

Water content of summer maize hybrids grown in China is too high at harvesting stage, which limits the development of grain mechanical harvesting technology. Spraying the desiccant can regulate physiological process of crop grain filling and reduce water content at harvest. We explored the effects of spraying the desiccant on the dehydration process, grain moisture, and grain quality of summer maize hybrids differing in maturity.

Effects of Urea-Ammonium Nitrate Solution on Yield, NO Emission, and Nitrogen Efficiency of Summer Maize Under Integration of Water and Fertilizer.

In order to clarify the effects of urea-ammonium nitrate solution (UAN) on the yield, nitrogen-use efficiency (NUE), and NO emissions of summer maize under the condition of water and fertilizer integration, different types of nitrogen fertilizer were selected, namely, ordinary urea (urea) and UAN. Our results showed that the application of UAN was beneficial to improve the dry matter accumulation and the distribution of summer maize. Compared with urea treatment, the total nitrogen accumulation of UAN treatment was increased by 15.

Responses of nitrogen efficiency and antioxidant system of summer maize to waterlogging stress under different tillage.

Waterlogging was one of the main abiotic stresses affecting maize yield and growth in the North China Plain, while ridge tillage effectually improved soil environment, enhanced crop stress resistance to waterlogging, and increased grain yield of waterlogged maize. In order to explore the responses of nitrogen (N) efficiency and antioxidant system of summer maize to waterlogging stress under different tillage, a field experiment was conducted to explore N use efficiency, leaf activities of superoxide dismutase (SOD), peroxidase (POD), and catalase (CAT), and malondialdehyde (MDA) content of waterlogged maize Denghai 605 (DH605) and Zhengdan 958 (ZD958) under different tillage system (ridge planting and flat planting). Our results showed that ridge tillage was beneficial to ameliorate waterlogging damages on antioxidant system by increasing SOD, POD, and CAT activities, and decreasing MDA content.

[Effects of phytase Q9 on the yield and senescence characteristics of summer maize shaded in the field].

Light shortage in the canopy of summer maize resulted from the decrease of solar radiation and the increase of planting density in Huanghuaihai region could reduce maize yield. In order to explore the effects of phytase Q9 on leaf senescence characteristics of summer maize, three sha-ding treatments with summer maize hybrid 'Denghai 605' (DH605) were conducted, including shading at flowering to maturity stage (S), shading at ear stage (S), and shading at whole growth stage (S) with natural lighting in the field as control (CK). Chemical control reagent phytase Q9 was used to regulate the shading treatments (the original solution was diluted by 100 times) and the CK exogenously, namely shading at flowering to maturity stage-phytase Q9 (SQ), shading at ear stage-phytase Q9 (SQ), and shading at whole growth stage-phytase Q9 (SQ), and natural lighting-phytase Q9 (CKQ), with spraying water at the same stage as the control.

Endogenous Hormones Inhibit Differentiation of Young Ears in Maize () Under Heat Stress.

Global warming frequently leads to extreme temperatures, which pose a serious threat to the growth, development, and yield formation of crops such as maize. This study aimed to deeply explore the molecular mechanisms of young ear development under heat stress. We selected the heat-tolerant maize variety Zhengdan 958 (T) and heat-sensitive maize variety Xianyu 335 (S), and subjected them to heat stress in the V9 (9th leaf), V12 (12th leaf), and VT (tasseling) growth stages.

Comparative proteomic analysis reveals that exogenous 6-benzyladenine (6-BA) improves the defense system activity of waterlogged summer maize.

Background: Exogenous 6-benzyladenine (6-BA) could improve leaf defense system activity. In order to better understand the regulation mechanism of exogenous 6-benzyladenine (6-BA) on waterlogged summer maize, three treatments including control (CK), waterlogging at the third leaf stage for 6 days (V3-6), and application of 100 mg dm 6-BA after waterlogging for 6 days (V3-6-B), were employed using summer maize hybrid DengHai 605 (DH605) as the experimental material. We used a labeling liquid chromatography-based quantitative proteomics approach with tandem mass tags to determine the changes in leaf protein abundance level at the tasseling stage.

[Effects of nitrogen application rate on grain filling characteristics and nutritional quality of summer maize.].

Suitable nitrogen application rate can significantly increase grain filling rate and yield and improve nutritional quality. Denghai 518 (DH518) and Zhengdan 958 (ZD958) were used as experimental materials in this study. A field experiment with four treatments, no nitrogen treatment (N), decrement nitrogen application rate (N, 129 kg N·hm), suitable nitrogen rate (N, 184.

Effects of residue management strategies on greenhouse gases and yield under double cropping of winter wheat and summer maize.

The North China Plain (NCP) is typically cropped using a winter wheat-summer maize double cropping system, which has huge potential for straw production. The region also experiences atmospheric pollution caused by straw burning, which has become an important contributor to global warming. The goals of this experiment were to resolve the conflict between soil fertility and greenhouse gas emission when using straw return to the field and to identify the best balance between environmental protection and agricultural production.

Response of Summer Maize Photosynthate Accumulation and Distribution to Shading Stress Assessed by Using CO Stable Isotope Tracer in the Field.

Maize is one of the most important crops globally that provides food, feed, and bioenergy. However, shading stress threatens maize production. In this study, we investigated the effects of shading on photosynthate accumulation and distribution of summer maize in the field.

Responses of Nitrogen Metabolism, Uptake and Translocation of Maize to Waterlogging at Different Growth Stages.

We performed a field experiment using the maize hybrids DengHai605 (DH605) and ZhengDan958 (ZD958) to study nitrogen uptake and translocation, key enzyme activities of nitrogen metabolism in response to waterlogging at the third leaf stage (V3), the sixth leaf stage (V6), and the 10th day after the tasseling stage (10VT). Results showed that N accumulation amount was significantly reduced after waterlogging, most greatly in the V3 waterlogging treatment (V3-W), with decreases of 41 and 37% in DH605 and ZD958, respectively. N accumulation in each organ and N allocation proportions in grains decreased significantly after waterlogging, whereas N allocation proportions increased in stem and leaf.

Effects of plant density on the photosynthetic and chloroplast characteristics of maize under high-yielding conditions.

Plant density has been recognized as a major factor determining the grain yield. The photosynthetic performance changes as the density increases. The main objective of this research was to evaluate responses of photosynthetic performance and chloroplast ultrastructure to planting densities in two summer maize (Zea mays L.

Effects of Waterlogging on Leaf Mesophyll Cell Ultrastructure and Photosynthetic Characteristics of Summer Maize.

A field experiment was performed to study the effects of waterlogging on the leaf mesophyll cell ultrastructure, chlorophyll content, gas exchange parameters, chlorophyll fluorescence, and malondialdehyde (MDA) content of summer maize (Zea mays L.) hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The waterlogging treatments were implemented for different durations (3 and 6 days) at the third leaf stage (V3), the sixth leaf stage (V6), and the 10th day after the tasseling stage (10VT).

Effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of summer maize.

A field experiment was conducted to study the effects of shading on the photosynthetic characteristics and mesophyll cell ultrastructure of two summer maize hybrids Denghai605 (DH605) and Zhengdan958 (ZD958). The ambient sunlight treatment was used as control (CK) and shading treatments (40 % of ambient sunlight) were applied at different growth stages from silking (R1) to physiological maturity (R6) (S1), from the sixth leaf stage (V6) to R1 (S2), and from seeding to R6 (S3), respectively. The net photosynthetic rate (P n) was significantly decreased after shading.

[Effects of tillage at pre-planting of winter wheat and summer maize on leaf senescence of summer maize].

This study explored the effects of different tillage treatments at pre-planting winter wheat and summer maize on leaf senescence physiological characteristics of summer maize in double cropping system. Zhengdan 958 was used as experimental material. Three tillage treatments, including rotary tillage before winter wheat seeding and no-tillage before summer maize seeding (RN), mold- board plow before winter wheat seeding and no-tillage before summer maize seeding (MN), and moldboard plow before winter wheat seeding and rotary tillage before summer maize seeding (MR), were designed to determine the effects of different tillage treatments on leaf area (LA) , leaf area reduction, photosynthetic pigments content, superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities and malondialdehyde (MDA) content in ear leaves of summer maize after tasselling (VT).