[Effects of tillage and fertility on soil nitrogen balance and greenhouse gas emissions of wheat-maize rotation system in Central Henan Province, China.] / 耕作和培肥对豫中区小麦-玉米轮作系统土壤氮平衡和温室气体排放的影响.

Energy saving, emission reduction, and efficiency improvement are important directions for agricultural development in Central Henan Province, the main grain production area in the Huang-huai-hai Plain. Based on the tillage and fertilization positioning experiment in 2010, we investigated the effects of three tillage methods (deep tillage, shallow tillage, and no-tillage) and two fertilization methods (nitrogen fertilizer and nitrogen fertilizer+organic fertilizer) on soil nitrogen balance and greenhouse gas emissions from 2018 to 2019. The results showed that soil nitrogen accumulation increased with organic fertilizer addition. During wheat and maize maturation, soil total nitrogen accumulation in the 0-60 cm layer was the highest under the treatment of shallow tillage+organic fertilizer, being 8058.53 and 8299 kg N·hm-2, respectively, being 3.2%-27.4% and 4.3%-7.2% higher than other treatments. The treatment with organic fertilizer addition resulted in nitrogen surplus. The shallow tillage+organic fertilizer treatment led to the highest nitrogen surplus (13.57 kg N·hm-2), which was 9.52 and 0.18 kg N·hm-2 higher than deep tillage+organic fertilizer and no tillage+organic fertilizer treatments. Nitrate leaching was the main way of nitrogen losses, accounting for 73.4%-76.9% of the total losses. The amount of nitrate leaching was the highest in deep tillage+organic fertilizer treatment (48.37 kg N·hm-2), being 18.9%-35.1% higher than other treatments. Results of greenhouse gases emission during 2018-2019 showed that global warming potential was the highest under the treatment of deep tillage+organic fertilizer, which was 33070 kg N·hm-2, being 6.6%-26.8% higher than other treatments. The treatment of organic fertilizer addition increased the emission of N2O and CO2 and reduced the absorption of CH4. The annual grain yield was highest under the treatment of deep tillage+organic fertilizer, which was 5.0%-17.1% higher than other treatments. The crop harvest index was the highest under the treatment of shallow tillage+organic fertilizer. The recommended cropping mode in Central Henan Pro-vince is shallow tillage+organic fertilizer, which could ensure crop yields, maintain soil nitrogen balance, and reduce greenhouse gas emissions.

[Effects of organic fertilizer application on accumulation and distribution of assimilates in winter wheat]. / å¢žæ–½æœ‰æœºè‚¥å¯¹å†¬å°éº¦åŒåŒ–ç‰©ç§¯ç´¯ä¸Žåˆ†é çš„å½±å“.

To understand the effects of organic fertilizer addition on accumulation and distribution of winter wheat assimilates, we compared organic carbon content in soil and wheat plants, photosynthetic characteristics and assimilation transformation under two different fertilizer treatments, CF (chemical fertilizer only) and OF (organic fertilizer with chemical fertilizer), using 13CO2 pulse labeling method. The results showed that OF increased soil organic carbon content and wheat photosynthetic parameters, resulting in higher organic carbon content and total dry biomass accumulation in wheat plants compared with CF treatment. Compared marking to maturity with that on the 7th day after the same marking, the content and distribution rate of 13C in leaves and stems of two treatments decreased; the 13C content in spikes increased at jointing stage and filling stage, decreased at anthesis stage, and the 13C distribution rate increased at all stages. OF treatment was more beneficial for the transportation of photosynthetic product from leaves to spikes at filling stage, with higher 13C distribution rate in spikes compared with CF treatment. The results of correlation analysis showed that dry matter accumulation was significantly positively correlated with the net input of 13C content and its distribution rate, but negatively correlated with organic carbon content in plants. The net input of 13C content was significantly positively correlated with its distribution rate, and negatively correlated with Fv/Fm and Pn. In conclusion, organic fertilizer application could increase the content of organic carbon in soil, improve wheat plants photosynthetic capacity and transportation of photosynthetic product to spikes, and ultimately increase dry matter accumulation in wheat spikes.

[Structure characteristics of soil and canopy and their relationships in wheat field under different tillage and application of organic fertilizer.] / è€•å±‚è°ƒæŽ§ä¸Žæœ‰æœºè‚¥å¤„ç†ä¸‹éº¦ç”°åœŸå£¤å’Œå°éº¦å† å±‚ç»“æž„ç‰¹æ€§åŠå ¶ç›¸äº’å ³ç³».

With the aim to optimize the structural characteristics of wheat canopy by improving topsoil structure, we examined the effects of three different tillage treatments, deep tillage (DT), shallow tillage (ST), no-tillage (NT) alone, and with application of organic fertilizer, DTF, STF and NTF, on the soil structure and wheat canopy characteristics for five years. Under the same tillage treatment, application of organic fertilizer decreased soil bulk density, the content of soil aggregates with diameter > 5 mm, the mean mass diameter (MWD), and geometric mean diameter (GMD) values of the soil aggregates with diameter >0.25 mm. Soil porosity and the content of soil aggregates with diameters of 2-5 mm and 0.25-2 mm at 20-40 cm soil layer were increased. Compared with other treatments, NTF was better in improving soil bulk density and increased soil porosity at 0-20 cm soil layer. DTF decreased the soil bulk density and the stability of mechanical aggregate with diameter > 0.25 mm at 40-60 cm soil layer, and increased soil permeability. Application of organic fertilizer decreased leaf angle index and increased leaf area index (LAI) and the net photosynthetic rate (Pn) of the flag leaf at post-anthesis stage. The lowest angle index and the highest Pn were detected in STF and DTF treatment, respectively. Results from path analysis showed that the direct path coefficients were significant from the independent variables (soil bulk density, soil porosity, R0.25 and MWD) to the dependent variables (angle index, LAI and Pn). At 0-20 cm soil layer, the increased MWD value was beneficial to the improvement of Pn and LAI. At 20-40 cm soil layer, the increased soil bulk density would optimize the leaf angle and further improve canopy light penetration. At 40-60 cm soil layer, high soil bulk density and low porosity negatively affected the value of LAI and Pn. We concluded that deep tillage or shallow tillage with application of organic fertilizer would be beneficial for improving soil structure, increasing soil permeability, optimizing wheat canopy structure, increasing canopy light harvesting rate, leaf area index and photosynthetic rate, with positive consequences on wheat yield.

[Identification and analysis of the NAC transcription factor family in Triticum urartu].

NAC transcription factors are one of plant-specific gene families with diverse functions, and they regulate plant development, organ formation and stress responses. Currently, the researches about NAC transcription factors mainly focus on model plants, Arabidopsis and rice, whereas such studies are hardly reported in wheat and other plants. In this study, the full-length coding sequences (CDS) of NAC transcription factors from Triticum urartu (TuNAC) were identified through bioinformatic analysis. Their biological function, evolutionary relationship, gene duplication and chromosomal locations were further predicted and analyzed. The quantitative real-time PCR (qRT-PCR) assay was used to verify the expression pattern of abiotic-related TuNAC transcription factors. A total of 87 TuNAC transcription factors with full-length CDS were identified, which were divided into seven subgroups through phylogenetic analysis. Thirty-nine TuNAC transcription factors were located on seven chromosomes, and five pairs of TuNAC transcription factors were duplicated. The expression of four TuNAC transcription factors was consistently increased under diverse abiotic stress by qRT-PCR assay. Our study thus provides basis for further functional investigations of TuNAC transcription factors.

[Effects of silicon on the ultrastructures of wheat radical cells under copper stress].

To explore the alleviation effect of silicon on wheat growth under copper stress, cultivar Aikang 58 was chosen as the experimental material. The growth, root activities and root tip ultrastructures of wheat seedlings, which were cultured in Hoagland nutrient solution with five different treatments (control, 15 mg x L(-1) Cu2+, 30 mg x L(-1) Cu2+, 15 mg x L(-1) Cu2+ and 50 mg x L(-1) silicon, 30 mg x L(-1) Cu2+ and 50 mg x L(-1) silicon), were fully analyzed. The results showed that root length, plant height and root activities of wheat seedlings were significantly restrained under the copper treatments compared with the control (P < 0.01), while these restraining effects were alleviated after adding silicon to copper-stress Hoagland nutrient solution. Under copper stress, the cell wall and cell membrane of wheat seedling root tips suffered to varying degrees of destruction, which caused the increase of intercellular space and the disappearance of some organelles. After adding silicon, the cell structure was maintained intact, although some cells and organelles were still slightly deformed compared with the control. In conclusion, exogenous silicon could alleviate the copper stress damages on wheat seedlings and cellular components to some extent.

[Application of ICP-MS/ICP-AES to detecting nutrition and heavy metal contents in grain of detached wheat spikes in vitro culture].

The heavy metals in the environment led to the defect of nutrient contents in grains and metabolic disturbance seriously. In order to research the effect of heavy metal copper and cadmium on nutrient contents and heavy metal contents of wheat grain, the present paper studied the nutrition element (P, K, Ca, Mg, Na, Fe, Mn, Zn and B) and contents of heavy metal (Pb, Cr, Hg, Cu and Cd) in organs of detached wheat spikes in vitro culture by ICP-MS/ICP-AES. The results showed that the weight of grain reduced significantly with copper and cadmium treatment. Under different copper treatment, the contents of P, K, Mg, Ca, Na, Mn and Zn increased, but Fe and B contents reduced. Exogenous cadmium promoted the absorption of P, K, Ca, Mg and Mn while interrupted the absorption of Na, Fe, Zn and B. Exogenous copper and cadmium treatment reduced the Hg content in wheat grain, but the Cu and Cd contents were 55-folds and 62 folds of the national food sanitation standard. All the data showed that the effects of copper and cadmium are disadvantageous to the accumulation of nutrient and heavy metal contents.