Effects of different densities of mixed-cropping on C-photosynthate distribution and grain yield of maize.

To explore the effects of different densities of mixed-cropping on C-photosynthate distribution and grain yield of maize, we measured photosynthetic characteristics, C-photosynthate distribution, dry matter accumulation, and grain yield under different planting densities (LD, 67500 plants·hm and HD, 97500 plants·hm) under mixed-cropping (M, 1:1, 2:2) and monoculture of Zhengdan958 (ZD) and Denghai605 (DH). The results showed that with the increases of planting density, grain yield, C-photosynthate allocation to grain, dry matter accumulation, and leaf area index (LAI) increased, but the chlorophyll content and net photosynthetic rate decreased. No significant difference was observed between the monoculture and mixed-cropping at the density of 67500 plants·hm.

[The interactive effects of water and nitrogen addition on ammonia volatilization loss and yield of winter wheat.].

An experiment with winter wheat of Shimai 15 and treatments of two types of fertilizers (organic manure, M; urea, U), two amounts of nitrogen application (180 kg·hm, MU; 90 kg·hm, MU), two irrigation levels (500 mm, W; 250 mm, W) was carried out in the lysimeters in 2015-2017. The results showed that ammonia volatilization was substantial after fertilization and irrigation. The dynami of ammonia volatilization during two years was similar.

[Effects of light intensities after anthesis on the photosynthetic characteristics and chloroplast ultrastructure in mesophyll cell of summer maize (Zea mays L. )].

We examined the changes of photosynthetic characteristics and chloroplast ultrastructure in mesophyll cell of summer maize in response to different light intensities in the field, with the summer maize hybrid Denghai 605 as experimental material. Two treatments of both shading (S) and increasing light (L) from flowering to physiological maturity stage were designed, with the ambient sunlight treatment as control (CK). Under shading treatment, poorly developed thylakoid structure, blurry lamellar structure, loose granum, large gap between slices and warping granum were the major characteristics in chloroplast.

[Effects of water conditions and controlled release urea on yield and leaf senescence physiological characteristics in summer maize.].

In an soil column experiment with Zhengdan 958 (a summer maize cultivar planted widely in China), treatments of three water levels,severe water stress W which the soil moisture kept (35±5)% of the field capacity, mild water stress W which was (55±5)%,normal water W which was (75±5)%, and four levels of controlled release urea fertilizer (N, N was 150 kg N·hm,N was 225 kg N·hm and N was 300 kg N·hm) were included to study the interactive effects of water and controlled release urea on yield and leaf senescence characteristics of summer maize. The results showed that the coupling of water and controlled release urea had significant effects on increasing yield, delaying the senescence and keeping the high efficiency of the functional leaves. Under the same nitrogen condition, yield, LAI, chlorophyll content and the activities of SOD, POD, CAT and soluble protein content in summer maize ear leaf were significantly increased with more water supplying, and the content of MDA decreased significantly.

[Effects of different cultivation practices on composition, carbon and nitrogen distribution of soil aggregates in farmlands.].

The long-term experiments were conducted at two locations with different soil fertility. There were four treatments, including super high-yielding cultivation treatment (SH), high-yielding and high efficiency cultivation treatment (HH), local farmer's practice (FP), and control (CK), respectively. The field experiments were established to study the effects of different cultivation practices on composition, carbon and nitrogen distribution of tillage layer soil aggregates in different soil fertility, with the aim of proposing technological approaches to enhance soil fertility and achieve the sustainable development of increasing yield and efficiency in wheat-maize ecosystem.

[Effects of sowing depth on seedling traits and root characteristics of summer maize].

Two summer maize hybrids, Zhengdan 958 (ZD958) and Xianyu 335 (XY335), were used as experimental materials. 4 sowing depths (3, 5, 7 and 9 cm) and uneven sowing depth (CK) were designed under sand culture and field experiments to investigate the effects of sowing depth on seedling traits and root characteristics of summer maize. The results showed that the seedling emergence rate gradually decreased and seedling emergence time gradually lengthened as the sowing depth increased.

[Effects of long-term mixed application of organic and inorganic fertilizers on canopy apparent photosynthesis and yield of winter wheat].

A field experiment was conducted using the winter wheat (Triticum aestivum) variety Shimai 15. The source of organic nitrogen was cow manure, and four fertilization treatments were included, i.e.

[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).

[Effects of irrigation and fertilization on soil microbial properties in summer maize field].

In order to investigate the effects of different irrigation and fertilization on soil microbial properties of summer maize field, we used ZN99 with high nitrogen use efficiency as the test material. The experiment adopted the split plot design which included two irrigation levels (526 mm and 263 mm) as the main plots, three fertilizer types (U, M, UM) and two fertilizer levels (N 100 kg . hm-2 and 200 kg .

[Effect of light from flowering to maturity stage on dry matter accumulation and nutrient absorption of summer maize].

Using Denghai 605 (DH4605) as the experimental material, shading (S) and increasing light (L) treatments from flowering to maturity stage were designed in a field experiment to explore effects of light on dry matter accumulation and nutrient absorption of summer maize. Results showed that grain yield, dry matter accumulation and nutrient absorption decreased significantly after shading but increased after increasing light. Yields in S treatment from 2011 to 2013 were reduced by 59.

[Effects of shading on endogenous hormones regulation in kernel development of summer maize in the field].

Taking 3 maize hybrids, Zhenjie 2 (ZJ2), Denghai 605 (DH605) and Zhengdan 958 (ZD958) as test materials, the effects of shading on the physiological function of endogenous hormones during grain formation of summer maize were investigated in the field. The ambient sunshine treatment was used as the control (CK) and 3 shading treatments with a shading degree of 60% were designed in growth periods ranging from tasseling to maturity (S1), from jointing to tasseling stage (S2) and whole growing period (S3), respectively. Results showed that the total floret number, filament number and pollination floret number decreased after shading in comparison with CK, and aborted seeds increased accordingly.

[Effect of waterlogging on leaf senescence characteristics of summer maize in the field].

Taking two summer maize hybrids Zhengdan 958 (ZD958) and Denghai 605 (DH605) as experimental materials, a field experiment was conducted to explore the effects of waterlogging for different durations (3 and 6 days) on leaf senescence characteristics of summer maize at the three-leaf stage (V3), six-leaf stage (V6), and 10 days after the tasseling stage (10VT). Results showed that superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activities and soluble protein content decreased significantly after waterlogging. However, the content of malondialdehyde (MDA) increased significantly by 35.

[Effects of row spacing on canopy structure and grain-filling characteristics of high-yield summer maize].

Using two summer maize (Zea mays L.) varieties Zhengdan 958 and Xianyu 335, a field experiment was conducted to study the regulatory effects of row-spacing (equidistant row and narrow-wide row) and plant-spot spacing arrangement (1 plant per spot, 2 plants per spot, 3 plants per spot) on grain yield components, canopy structure and photosynthetic characteristics after anthesis under plant population density 7.5 x 10(4) plants x hm(-2).

[Effects of shading on dry matter accumulation and nutrient absorption of summer maize].

Taking summer maize cultivars Zhenjie 2 (ZJ2), Denghai 605 (DH605), and Zhengdan 958 (ZD958) as test materials, a field trial was conducted to study the effects of shading on the dry matter accumulation and nitrogen (N), phosphorus (P) and potassium (K) absorption of summer maize. Four treatments were installed, i. e.

Exogenous calcium alleviates photoinhibition of PSII by improving the xanthophyll cycle in peanut (Arachis hypogaea) leaves during heat stress under high irradiance.

Peanut is one of the calciphilous plants. Calcium (Ca) serves as a ubiquitous central hub in a large number of signaling pathways. The effect of exogenous calcium nitrate [Ca(NO3)2] (6 mM) on the dissipation of excess excitation energy in the photosystem II (PSII) antenna, especially on the level of D1 protein and the xanthophyll cycle in peanut plants under heat (40°C) and high irradiance (HI) (1 200 µmol m(-2) s(-1)) stress were investigated.

Optimisation of antioxidant peptide preparation from corn gluten meal.

Background: Corn gluten meal, containing approximately 600 g kg(-1) protein, is a main by-product of corn wet milling. The annual output of corn gluten meal in China is over 840 000 tons. However, it is difficult to utilise corn gluten meal in the food industry because of its low water solubility and amino acid imbalance.

[Effects of partial root excision on the growth, photosynthesis, and antioxidant enzyme activities of maize under salt stress].

A pot experiment was conducted to study the effects of partial root excision on the growth of two maize cultivars (Zhengdan 958 and Denghai 9) throughout their growth period and the photosynthesis and leaf antioxidant enzyme activities at grain-filling stage under salt stress. Four treatments were installed, i. e.

[Effects of nitrogen application period on the nitrogen metabolism key enzymes activities and antioxidant characteristics of high-yielding summer maize].

Taking the high-yielding summer maize cultivars Denghai 661 (DH661) and Zhengdan 958 (ZD958) as test materials, a field experiment was conducted to study their grain yield, nitrogen use efficiency, key enzymes activities of nitrogen metabolism, and antioxidant enzymes activities under effects of different nitrogen application periods. One-dose nitrogen application at jointing stage was not beneficial to the increase of grain yield and the nitrogen accumulation in plant and grain, while split application in combination with application after anthesis increased the nitrogen accumulation in plant and grain significantly and increased the grain yield. When the nitrogen was applied at a ratio of 2:4:4 at jointing stage, 10-leaf stage, and 10 days after anthesis, the grain yield of DH661 was up to 14123.

[Effects of applying selenium on selenium allocation, grain yield, and grain quality of two maize cultivars].

A pot experiment with conventional maize cultivar ZD958 and glutinous maize cultivar JN218 was conducted to study the effects of applying different concentrations (0, 10, 25 and 50 mg x kg(-1)) of selenium (Se) on the Se allocation in plant organs, grain yield, and its quality. At low concentrations (< or = 10 mg x kg(-1)), Se stimulated maize growth, and increased biomass accumulation and grain yield significantly. At high concentrations (> 25 mg x kg(-1)), Se inhibited maize growth, and decreased dry mass accumulation, grain yield, and its quality.

[Present situation of maize straw resource utilization and its effect in main maize production regions of China].

A survey was carried out in three main maize production regions in Northeast, North, and Southwest China, including 720 villages of 125 counties, with the purpose of investigating the present situation of maize straw resource utilization and its effect. Among the present utilization ways of maize straw resource, the main ones were returning to soil, feeding livestock, and using as fuel, their proportions being 30.8%, 26.

[Effects of arsenic on maize growth, antioxidant system, and ion distribution].

A greenhouse sand culture experiment was conducted to study the effects of arsenic (As) on the biomass accumulation, photosynthetic pigments, antioxidant system, and the absorption and distribution of As and mineral ions in maize Zhengdan 958. At lower concentrations (<2 mg As x L(-1)), As stimulated the growth of maize seedlings, and increased the plant height, taproot length, and biomass accumulation significantly; at higher concentrations (>4 mg As x L(-1)), As inhibited the seedlings growth severely. At 2 mg As x L(-1), the chlorophyll a, b, and a+b contents reached their peaks; but with increasing As concentration, the chlorophyll contents decreased gradually.

[Effects of planting density on the grain yield and source-sink characteristics of summer maize].

Taking high-yielding summer maize cultivars Zhengdan 958 (ZD 958) and Denghai 661 (DH 661) as test materials, this paper studied the effects of different planting density (22500, 45000, 67500, 90000, and 112500 plant x hm(-2)) on the grain yield and source-sink characteristics of the cultivars in four regions, i.e., Shandong Agricultural University, Wenkou, Yanzhou, and Laizhou.

[Effects of cropping patterns on photosynthesis characteristics of summer maize and its utilization of solar and heat resources].

In order to investigate the effects of interplanting and direct seeding on the photosynthesis characteristics of summer maize and its utilization of solar and heat resources, two summer maize cultivars (Zhengdan 958 and Denghai 661) were planted in the farmlands of Denghai Seed Co. Ltd in Laizhou City of Shandong Province, with 67500 plants x hm(-2) and three sowing dates. The above-ground biomass, plant growth rate, leaf area index, and net photosynthetic rate per ear leaf were measured to reveal the photosynthesis characteristics of test cultivars.

[Leaf redundancy of high-yielding maize (Zea may L.) and its effects on maize yield and photosynthesis].

According to the maize yield at plant density of 15000 ind x hm(-2) in 2007, the leaf-redundant type (cultivar Chaoshi 1) and non-redundant type (cultivar Chaoshi 3) at low plant density were selected, and the changes of their above-ground dry matter accumulation and grain yield after cutting all leaves to 1/2 (T1) and 1/4 (T2) at anthesis at the optimal density and under high-yielding condition were analyzed in 2008, aimed to approach whether the leaf redundancy exists in high-yielding maize colonies. The characters of grain-filling were simulated by Richards' model, and the photosynthetic characteristics and chlorophyll fluorescence of the leaves on ear position were determined to reveal the activities of photosynthesis after the removal of redundancy. The results showed that at optimal plant density and under high-yielding condition, both the redundant and non-redundant types had leaf redundancy.