Abstract

Wheat (Triticum aestivum L.) is one of the most important food crops in the world order to understand the regulatory effects of nitrogen density interaction on starch distribution and gelatinization characteristics of wheat grains, Huaimai-44 was used as the material three nitrogen application levels (120, 180 and 240 kg ha-1) and three planting density levels (1.8 million, 2.4 million and 3 million plants kg ha-1) were analyzed differences in grain starch size distribution and viscosity parameters of wheat under different nitrogen density treatments. The results showed that with the increase of nitrogen application level, wheat kernel starch grain volume and surface area percentage of type B (particle size ≤10μm). A decreasing trend, while starch grain volume and surface area percentage of type A (particle size >10μm) showed a decreasing trend on the rise. With the increase of planting density, the grain volume and surface area percentage of B-type starch increased first and then decreased, and the A-type starch granules increased percentage of volume and surface area decreased first and then increased. Among B-type starch granules, nitrogen and planting density had greater effects on 2.8-10 μm starch granules. Type among starch grains, nitrogen and planting density had greater effects on starch grains >22μm. Nitrogen and planting density had no significant influence on the percentage of starch grain number. Wheat starch viscosity parameters such as peak viscosity, trough viscosity and final viscosity increased significantly with the increase of nitrogen application level, and with the increase of planting density level of improvement decreased significantly. Nitrogen application and densification increased grain protein content, wet gluten content and wheat yield. Wheat is applied with nitrogen grain size distribution of endosperm starch was affected by increasing the proportion of A-type starch granules and decreasing the proportion of B-type starch granules. Nitrogen application increased starch viscosity densification reduced the starch viscosity parameter, and then improved the grain yield and processing quality of wheat.

1. Introduction

Starch is an important component of wheat kernel, accounting for about the kernel stem 65% to 70% of the weight is also the reason for determining the yield and quality of wheat one of the elements ^{1, 2}. Starch size distribution and viscosity parameters of flour chemical characteristics determine its processing quality. Among them, starch is characteristic in industry application with steamed bread, noodles, bread quality and starch are important influence ^{3, 4, 5, 6}. Viscosity parameters not only affect the appearance of noodles and steamed buns, but also it affects its texture and taste, so the starch viscosity parameter can be used as a surface evaluation index of quality of strips and steamed buns ^{7, 8}. Wheat large and small starch granules it has different structural characteristics and physical and chemical properties, resulting in differences starch properties of wheat, in turn, affect wheat quality ⁹. The cultivation environment affects the grain size distribution and chemical characteristics of wheat starch important factor of sex. Suitable nitrogen application rate and planting density can promote the growth and development of wheat and the formation of grain quality of wheat significant regulatory effect ^{10, 11}. The study found that strong gluten wheat varieties after the application of nitrogen fertilizer, the B-type starch decreased significantly, while the moderate gluten and weak gluten variety of B type starch increased significantly, starch viscosity parameters also have ¹². Planting density on starch grain size distribution in wheat endosperm regulatory effect is obvious, and there are genotype differences in its influence ¹³. In protein content of wheat grain after nitrogen fertilizer was applied within the suitable nitrogen application range content, wet gluten content and sedimentation value were significantly increased ^{14, 15}. Augment planting density will reduce wheat dough formation time, stability time and settlement value ¹⁶. Most previous studies focused on nitrogen fertilizer and planting density influence of degree on wheat quality and the interaction of nitrogen density on wheat lake particle size distribution and chemical properties of the powder are less studied. This test is small wheat variety huaimai-44 was used as the material with different nitrogen application and planting density Wheat grain under different nitrogen application and planting density was studied changes of starch grain distribution and viscosity parameters were studied effects of starch grain distribution and gelatinization characteristics on wheat grain were studied provides theoretical basis for high yield and high quality cultivation and deep processing and utilization of wheat.

2. Materials and Methods

The experiment was conducted in Anhui Province from October 2020 to May 2021College of Technology farm. The test material was wheat variety Huaimai forty-four. The experiment was conducted in a randomized complete block design with three nitrogen levels (120, 180, and 240 kg ha^-1 are listed as N1, N2, and N3, respectively) and three density levels (1.8 million, 2.4 million, and three million plants ha^-1, represented by D1, D2, D3). The area of the community is 9 m2, repeat three times. The previous stubble in the experimental field was corn, and the soil type was clay loam, soil surface organic matter, alkali-hydrolyzed nitrogen, available potassium and available phosphorus contents were 16.65 mg·kg^-1 and 72.75 mg^-1 respectively 96.05 mg·kg^-1 and 17.45 mg·kg^-1. Nitrogen, phosphorus and potassium were urea (N 46%) and superphosphate, respectively. (P2O512%), potassium chloride (K2O 60%). Phosphate fertilizer (P2O5). Potassic fertilizer (K2O) was all under applied, and the application amount was 90 kg ha^-1, the basis ratio of nitrogen fertilizer was 7:3, and the application period was jointing stage. Wheat mechanical drill sowing November 6, 2020, June 1, 2021.

Daily harvest, other field management with conventional field production.

The methods were improved extract starch. At maturity, weigh 2g wheat and put it into the marked wheat add an appropriate amount of distilled water into the centrifuge tube and soak for 24h to remove the seeds the skin and endosperm are homogenized in a mortar and filtered on a 200-mesh sieve cloth. The retained sediment is repeatedly ground 2 to 3 times. After 3000 centrifuge at rpm for 10min, remove the supernatant and add 5mL2μmol L-1 NaCl, vortex mixing, homogenate centrifugation, repeated many times. Same Methods the samples were cleaned with 0.2% NaOH 2% SDS and distilled water

Time ^{17, 18}. Finally, clean with acetone three times, air dry, bag, store At -15°C. Us Baxter (BT-9300SE) laser is used particle size distribution meter is operated.

Starch viscosity parameters are marked by AACC operating steps quasi - procedural measurement. Say 3g wheat flour grinding mill put the powder into the aluminum box, add 25mL distilled water and stir evenly starch viscosity parameters were determined by Supper3 fast viscosity analyzer test was repeated three times for each sample.

Select wheat with uniform growth at heading stage and treat each weight compound area takes 1m2, and the survey is effective by measuring 1m per line with a wooden ruler ear grains were investigated at wheat maturity stage (May 29, 2021). The yield was measured at the mature stage, and each repeated plot was treated take 1m2, each row take 1m, sorting, drying, threshing, testing seeds, testing set thousand grain weight and repeat three times.

Wheat is harvested at the ripe stage and stored in the freezer after harvest two months, using the DA7200 NIR score of the Swedish company Broadcom content of protein and wet gluten in wheat grain was determined by analyzer.

Use Excel2016 and DPS7.0 for data statistics analyze.

3. Results

Nitrogen application and planting density are percentage of starch grain volume and surface area both ratios had a significant effect (Table 1, Table 2). At the same planting density with the increase of nitrogen application level, wheat grain B type starch granules (Particle size ≤10μm) the percentage of volume and surface area decreased while the A-type starch granules (diameter >10μm) showed an increasing trend. The results indicated that the growth of type A starch granules was facilitated by increasing nitrogen fertilizer. In the same with the increase of planting density under nitrogen application level, wheat grain B volume and surface area percentage of starch granules increased first and then decreased. The A-type starch granules decreased first and then increased, indicating that it was suitable for planting density is beneficial to the formation and growth of B-type starch granules. In the B-lake the powder grains, nitrogen application and planting density were 2.8-10 μm starch grains. The effect of starch granule group was greater than that of starch granule group <2.8μm. In type starch effects of nitrogen application and planting density on starch granule group >22μm noise was larger than that of starch granule group 10~22μm.

The number of B-type starch granules in wheat grains accounted for 99 percent of the total 80%~99.89%, the number of type starch granules accounted for 0. 11%~ 0.20% indicated that the grain number of wheat starch was B-type starch grain based. Nitrogen application and planting density on wheat starch grain number percentage ratio had no significant effect (Table 3).

Nitrogen application and planting density had significant effects on wheat starch viscosity parameters (Table 4). The same planting density, with the level of nitrogen application increase the viscosity of starch peak viscosity, trough viscosity, and final viscosity so on all the parameters showed an increasing trend. Under the same nitrogen application level, with the seed increase of plant density, starch peak viscosity, trough viscosity and final viscosity parameters such as degree showed a decreasing trend. It's at N3D1. The viscosity parameters are the highest. This indicates increased nitrogen application and decreased density it can improve the starch gelatinization characteristics of wheat grain.

The effects of nitrogen application and planting density on wheat panicle number, grain number per panicle and thousand grains both weight and yield had significant effects (Table 5). The same planting density with the increase of nitrogen application level, panicle number, grain number per panicle, 1000-grain weight were significantly increased output showed an upward trend. At the same nitrogen application level, with number of panicle increased with the increase of planting density, and the number of grains per panicle was 1000 grain weight showed a decreasing trend, and the yield showed a decreasing trend first and then increasing. In the treatment of 240 kg ha^–1 and 3 million strains yields the most.

Nitrogen application had significant effects on wheat grain protein content and wet gluten content was no significant effect on planting density (Table 6). Along with content of protein and wet gluten increased with the increase of nitrogen level However, there was no significant difference between N2 and N1, indicating excessive nitrogen application after that, the effect of improving grain quality decreased.

4. Discussion

Starch grain size distribution and physicochemical properties of wheat grain are affected by genes type control is also affected by cultivation environment factors, and environmental factors influence is greater than genotype ¹⁹. Studies have shown that increased nitrogen fertilizer can promote growth of wheat type A starch granules increases their number and surface area by one hundred fraction, reduce the number, volume and surface area of B-type starch granules score ratio ²⁰. With the increase of planting density level, wheat A-type lake powder particles have increased ¹³. This study shows that with the level of nitrogen application percentage of volume and surface area of wheat B type starch granules was increased percentage of volume and surface area of A-type starch granules showed an upward trend Upward trend; With the increase of planting density level, wheat grain B percentage of starch granule volume and surface area increased first and then decreased, A volume percentage of starch granules decreased first and then increased. In type B in starch grains, nitrogen application and planting density were 2.8-10 μm starch effect of starch granule group was greater than that of starch granule group <2.8μm. In the A-lake influence of nitrogen and density on starch granule group >22μm was higher starch granules of 10~22μm are large. Nitrogen application and planting density on starch percentage of grain number had no significant effect, possibly due to wheat grain deposition number of starch grains <2.8μm accounted for a larger proportion in the powder grains. It can be seen that nitrogen application is beneficial to the growth of starch granules of type and densification is beneficial to the growth of starch granules of type B formation and growth of type starch granules are favorable. Viscosity parameter is an important index for evaluating starch quality ²¹. The viscosity parameters of starch are affected by growing environment, nitrogen fertilizer, planting density, Effects of agronomic measures. Nitrogen application had certain effect on starch quality of wheat improvement effect ²². This is the adjustment of wheat flour viscosity with nitrogen fertilizer control effect is related ²³. This study shows that with the increase of nitrogen application level high, wheat grain starch peak viscosity, trough viscosity, and final viscosity iso-viscosity parameters were obviously increased. With the increase of planting density level high, grain starch peak viscosity, trough viscosity, final viscosity and so on

The index of degree parameters decreased significantly, among which the amount of nitrogen applied was 240 kg ha^–1 wheat seeds under planting density of 1.8 million plants hm^-2 grain starch gelatinization has the best properties. Nitrogen application and planting density can improve grain yield and quality of wheat it plays an important role in building a reasonable group structure and promoting production synergistic improvement of three elements of quantity. Studies have shown that nitrogen application can promote small number of ears, grains per ear and 1000-grain weight of wheat were greatly increased, and the yield was eventually increased ²⁴. The increase of planting density, wheat yield and number of grains per spike. It showed a trend of first rising and then decreasing ¹⁴. In this study, with the level of nitrogen application grain yield, spike number, spike number and 1000-grain weight of wheat were all increased upward trend is consistent with the results of previous studies. But with the planting dense with the increase of degree, the number of ears, the number of grains per ear and the 1000-grain weight of wheat showed an increasing trend. It showed a downward trend, and the yield showed a downward trend and then an upward trend, which was consistent with previous studies fruit is different. This may be due to an increase in planting density, although small number of wheat ears increased significantly, but because of the light transmittance and ventilation in the field poor, light energy effect weakened, resulting in smaller ears and fewer grains per ear, it affects grain filling and is not conducive to wheat yield formation. Visible, suitable nitrogen application amount and planting density can be beneficial to wheat yield high. Increased nitrogen application significantly increased wheat grain protein content, wet gluten content and sedimentation value ¹⁵. With the increase of planting density, Wheat grain protein content, wet gluten content and sedimentation value were presented first rising and then falling trend ²⁵. This study shows that in 120~240 kg ha^–1 nitrogen application range, increased nitrogen application can improve wheat grain contents of protein and wet gluten were consistent with the results of previous studies. Dan species effect of plant density on the content of protein and wet gluten was not significant. It is inconsistent with the results of previous studies. This may be due to different research density levels set by the study are different, and the specific reasons remain to be explored one step deeper study.

5. Conclusion

This study showed that nitrogen application and increased planting density were modulated grain size distribution characteristics of wheat starch were controlled, that is, the A-type starch grain ratio was increased the proportion of B-type starch granules was reduced, and then the starch viscosity parameter was changed number, that is, the application of nitrogen increased the viscosity parameters such as the peak viscosity of starch, and increased the density viscosity parameters such as starch peak viscosity were reduced, and then the viscosity was increased by a small amount grain yield and secondary processing quality of wheat.

ACKNOWLEDGEMENTS

Key Technologies, Products, and Applications of Smart Water and Fertilizer Regulation and Nutrient Synergistic Enhancement. (2021YED1901003)

References