前期研究表明，在玉米大斑病菌中存在9个漆酶样多铜氧化酶，其中漆酶基因StLAC2敲除导致黑色素含量降低，不能产生分生孢子，直接影响侵染能力。为进一步研究漆酶基因家族基因在生物学功能上的差异，本文利用同源重组技术创制StLAC6基因敲除突变体并对其对玉米大斑病菌生长发育、致病、杀菌剂抗性等方面的作用进行研究。结果表明通过同源重组技术成功创制了2株StLAC6基因敲除突变体，分析发现StLAC6基因缺失后对玉米大斑病菌的生长、菌丝形态和侵染能力没有显著影响，而且突变体细胞壁及细胞膜功能均正常。进一步对其超微结构进行分析发现，StLAC6基因敲除突变体菌丝中的过氧化物酶体形态异常，影响了菌丝内脂滴合成，同时敲除突变体中的酚类化合物和黑色素的合成增加。通过比较野生型和突变体的EC50值，发现StLAC6敲除导致病菌对嘧菌环胺、三环唑、吡唑醚菌酯等多种常见杀菌剂的敏感性增加，表明漆酶参与了玉米大斑病菌对杀菌剂的抗性。为了明确漆酶基因家族成员的关系，对StLAC6敲除突变体中其他漆酶基因的表达进行分析，发现StLAC1等多个玉米大斑病菌漆酶基因的表达水平发生了显着变化，说明漆酶基因家族成员间存在功能互补。本文为研究植物病原真菌中漆酶基因家族的功能和相互关系提供了新的见解。

增加种植密度是提高玉米产量的有效措施。然而，密植容易引发植物的避荫反应综合征，导致抗倒伏能力下降，最终导致产量降低。光敏色素B（phyB）在植物避荫反应中起主导作用。研究表明，将拟南芥PHYB(AtPHYB)104和361位的酪氨酸(Y)改变为苯丙氨酸(F)可以增强其活性。在本研究中，我们通过模拟AtPHYB的Y104F和Y361F的突变形式，创制了两个玉米PHYB1超敏突变体: ZmPHYB1^Y98F和ZmPHYB1^Y359F。在ZmPHYB1自身启动子的驱动下，将ZmPHYB1^Y98F、ZmPHYB1^Y359F和野生型的ZmPHYB1 (ZmPHYB1^WT)转入到拟南芥phyB-9突变体中。在转基因拟南芥中，与ZmPHYB1^WT相比，异源表达ZmPHYB1^Y98F和ZmPHYB1^Y359F增强了对phyB-9相关表型的互补功能。与ZmPHYB1^WT相似，红光处理可诱导ZmPHYB1^Y98F和ZmPHYB1^Y359F蛋白从细胞质中转运到细胞核，并且能够与玉米中的PIF蛋白互作。此外，在模拟遮荫处理下，ZmPHYB1自身启动子驱动的ZmPHYB1^Y98F和ZmPHYB1^Y359F在转基因玉米中的表达可以减弱玉米幼苗的避荫反应综合征，还能够降低玉米植株的株高和穗位高。综上所述，研究结果表明ZmPHYB1^Y98F和ZmPHYB1^Y359F能够减弱玉米的避荫反应综合征，为培育耐密玉米品种提供了新思路。

夏玉米品种及其种植密度是影响玉米抗倒伏能力的主要因素。本试验从木质素代谢的角度来探究不同玉米品种的抗倒伏能力及其种植密度调控。研究结果表明，抗倒伏夏玉米品种登海605 （DH605）具有较低的重心和良好的茎秆形态特征，这是其抗倒伏能力显著高于浚单20（XD20）的原因之一。DH605的木质素积累量、木质素合成途径关键酶活性以及G、S和H型木质素单体含量均显著高于XD20。随着种植密度的增加，两种品种的茎秆机械强度、木质素积累量和木质素合成途径关键酶活性均显著降低，G型木质素单体含量呈现先减少后保持稳定的趋势，S型木质素单体含量呈下降趋势，H木质素型单体含量呈上升趋势。相关性分析表明，倒伏率与植株性状及木质素代谢显著相关。因此，抗倒伏能力强的玉米具有木质素积累量高、木质素合成途径关键酶活性高、S型单体含量高、重心低、茎穿刺强度高、皮质厚度高、维管束面积小等特点，同时，高种植密度降低了茎秆木质素的积累、酶活性和机械强度，进而导致倒伏率提高。

Compared with single agronomic practices management during grain formation, knowledge about integrated agronomic practices management on grain-filling characteristics and physiological function of endogenous hormones was limited.  In order to clarify this issue, two field experiments, integrated agronomic practices management (IAPM), T1 (local conventional cultivation practices), T2 (an optimized combination of cropping systems and fertilizer treatment), T3 (treatment based on high-yield studies), and T4 (further optimized combination of cropping systems and fertilizer treatment), and nitrogen rate testing (NAT) (four nitrogen rates, 0, 129.0, 184.5, and 300.0 kg N ha^–1) were performed with summer maize hybrid Zhengdan 958 (ZD958). Results showed that with increased nitrogen rate, the endogenous hormone balance was promoted and the grain-filling characteristics were improved sufficiently to resulting in a significant increase in grain yield.  However, the grain-filling characteristics deteriorated and yield was reduced with excessive nitrogen fertilization.  However, IAPM could promote hormone balance and improve grain filling characteristic.  The indole-3-acetic acid (IAA), zeatin riboside (ZR), and gibberellin (GA₃) contents under T2 and T4 treatments were higher and the abscisic acid (ABA) content was lower, and the ZR and GA₃ contents under T3 were higher than those under T1.  Those resulted in the maximum grain-filling rate (W_max) and the active grain-filling period (P) under T2, T3 and T4 were significantly increased than those under T1, and hence promoted kernel weight and grain yield.  So IAPM promoted hormone balance by improving tillage model, optimizing fertilizer rate and fertilization period, appropriately increasing planting density and delaying harvest, which promoted grain filling rate and lengthened active grain-filling period, finally increased grain yield.

Improved estimates of nutrient requirements for rice (Oryza sativa L.) in China are essential to optimize fertilization regulation for increasing grain yields and reducing the potential of environmental negative influences, especially under high-yielding intensive systems. A database involving rice grain yields, nutrient concentrations and accumulations collected from on-field station experiments in the literatures published from 2000 to 2013 in China was developed to understand the relationships between grain yields and plant nutrient uptakes, and to quantify nutrient requirements for different yield levels. Considering all data sets, rice grain yield ranged from 1.4 to 15.2 t ha^–1 with the mean value of 7.84 t ha^–1, and ca. 10.4% of yield observations were higher than the yield barrier level of 10 t ha^–1. N requirement to produce one ton grain was 21.10 kg for the yield range <4.0 t ha^–1 with a high variation of 45.8%. Except of the yield range <4.0 t ha^–1, the values of N requirement, firstly increased from 18.78 kg for yield range 4.0–5.5 t ha^–1 to 20.62 kg for yield range 7.0–8.5 t ha^–1, then decreased slightly to 19.67 and 19.17 kg for the yield range 8.5–10 and >10 t ha^–1, respectively. Phosphorus (P) and potassium (K) requirements showed increasing trends, from 3.51 and 19.87 kg per t grain for <4.0 t ha^–1 yield range to 4.10 and 21.70 kg for >10.0 t ha^–1 range. In conclusion, nutrient requirement varied with increasement of grain yield, and N, P and K presented various response trends, increasing, declining or stagnating, which would be of great benefit for improving fertilizer strategies.

      Planting at an optimum density and supplying adequate nitrogen (N) to achieve higher yields is a common practice in crop production, especially for maize (Zea mays L.); however, excessive N fertilizer supply in maize production results in reduced N use efficiency (NUE) and severe negative impacts on the environment. This research was conducted to determine the effects of increased plant density and reduced N rate on grain yield, total N uptake, NUE, leaf area index (LAI), intercepted photosynthetically active radiation (IPAR), and resource use efficiency in maize. Field experiments were conducted using a popular maize hybrid Zhengdan 958 (ZD958) under different combinations of plant densities and N rates to determine an effective approach for maize production with high yield and high resource use efficiency. Increasing plant density was clearly able to promote N absorption and LAI during the entire growth stage, which allowed high total N uptake and interception of radiation to achieve high dry matter accumulation (DMA), grain yield, NUE, and radiation use efficiency (RUE). However, with an increase in plant density, the demand of N increased along with grain yield. Increasing N rate can significantly increase the DMA, grain yield, LAI, IPAR, and RUE. However, this increase was non-linear and due to the input of too much N fertilizers, the efficiency of N use at N_CK (320 kg ha^–1) was low. An appropriate reduction in N rate can therefore lead to higher NUE despite a slight loss in grain production. Taking into account both the need for high grain yield and resource use efficiency, a 30% reduction in N supply, and an increase in plant density of 3 plants m^–2, compared to LD (5.25 plants m^–2), would lead to an optimal balance between yield and resource use efficiency.

As the most important organ in plant photosynthesis, the leaf plays an important role in plant growth and development. Leaf senescence is associated with fundamental changes in the proteome. To research the molecular mechanisms of leaf senescence, protein expression in senescing maize ear leaves grown under field conditions was analyzed using two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionisation time-of-flight/time-of-flight mass spectrometry (MALDI-TOF/TOF MS). A total of 60 senescence-associated proteins were identified. The identified proteins are involved in many biological processes, especially energy, metabolism and protein synthesis. Several of the identified proteins have not been previously reported as senescence-associated, including glycine-rich RNA-binding protein.

Improving the yield of maize grain per unit area is needed to meet the growing demand for it in China, where the availability of fertile land is very limited. Modified fertilization management and planting density are efficient methods for increasing crop yield. Field experiments were designed to investigate the influence of modified fertilization management and planting density on grain yield and nitrogen use efficiency of the popular maize variety Zhengdan 958, in four treatments including local farmer’s practice (FP), high-yielding and high efficiency cultivation (HH), super high-yielding cultivation (SH), and the control (CK). Trials were conducted in three locations of the Huang-Huai-Hai Plain in northern China. Compared with FP, SH was clearly able to promote N absorption and dry matter accumulation in post-anthesis, and achieve high yield and N use efficiency by increasing planting density and postponing the supplementary application of fertilizers. However, with an increase in planting density, the demand of N increased along with grain yield. Due to the input of too much N fertilizer, the efficiency of N use in SH was low. Applying less total N, ameliorating cultivation and cropping management practices should be considered as priority strategies to augment production potential and finally achieve synchronization between high yield and high N efficiency in fertile soils. However, in situations where soil fertility is low, achieving high yield and high N use efficiency in maize will likely depend on increased planting density and appropriate application of supplementary fertilizers postpone to the grain-filling stage.

A endochitinase gene (Tch) from the fungus Trichoderma viride was introduced into broccoli (Brassica oleracea var. italica) by Agrobacterium-mediated transformation. Sixty-eight putative transformants were obtained and the presence of the Tch gene was confirmed by both PCR and Southern blot analysis. RT-PCR analysis showed an accumulation of the transcript encoding the endochitinase protein in the transgenic plants. Using real-time quantitative PCR, the expression profiling of endochitinase gene was analyzed. Primary transformants and selfed progeny were examined for expression of the endochitinase using a fluorometric assay and for their resistance to the pathogenic fungi Botrytis cinerea and Rhizoctonia solani. The endochitinase activities in T0 in vitro plants, T0 mature plants and T1 mature plants were correlated with leaf lesions, and the transgenic line T618 had high endochitinse activities of 102.68, 114.53 and 120.27 nmol L–1 MU min–1 mg–1 protein in the three kinds of plants, respectively. The endochitinase activity showed a positive correlation with the resistance to the pathogens. Most transgenic T0 broccoli had increased resistance to the pathogens of B. cinerea and R. solani in leaf assays and this resistance was confirmed to be inheritable. These findings suggested that expression of the Tch gene from T. viride could enhance resistance to pathogenic fungi in Brassica species.

Proper application of nitrogen (N) fertilizers and irrigation management are important production practices that can reduce nitrate leaching into groundwater and improve the N use efficiency (NUE). A lysimeter/rain shelter facility was used to study effects of the rate of N fertilization, type of N fertilizer, and irrigation level on key aspects of winter wheat production over three growing seasons (response variables were nitrate transport, N leaching, and NUE). Results indicated that nitrate concentration in the soil profile and N leaching increased with the rate of N fertilization. At the end of the third season, nitrate concentration in the top 0–75 cm layer of soil was higher with manure treatment while urea treatments resulted in higher concentrations in the 100–200 cm layer. With normal irrigation, 3.4 to 15.3% of N from applied fertilizer was leached from the soil, yet no leaching occurred under a stress irrigation treatment. The manure treatment experienced less N leaching than the urea treatment in all cases except for the 180 kg N ha-1 rate in 2011–2012 (season 3). In terms of grain yield (GY), dry matter (DM) or NUE parameters, values for the manure treatment were lower than for the urea treatment in 2009–2010 (season 1), yet were otherwise higher for urea treatment in season 3. GY and crop nitrogen uptake (NU) were elevated when the rate of N fertilizer increased, while the NUE decreased; GY, DM, and NU increased with the amount of irrigation. Data indicated that reduced rates of N fertilization combined with increased manure application and proper irrigation management can lower nitrate levels in the subsoil and reduce potential N leaching into groundwater.

Polyimide (PI) is a type of important membrane material. A soluble polymer was synthesized from 4,4´-(hexafluoroisopropylidene) diphthalic anhydride (6FDA) and 2,2-bis[4-(4-aminophenoxy) phenyl] hexafluoropropane (BDAF) by the two-step polymerization method. The polymer was proved to be polyimide 6FDA-BDAF by the Fourier transform infrared (FT-IR), the 1H-NMR and 19F-NMR spectra. An asymmetric membrane was prepared with the synthesized polyimide 6FDA-BDAF, it was porous in the 50 μm height bulk and dense in a 3–5 μm height surface. The membrane was used to separate n-heptane/ thiophene mixtures by pervaporation with sulfur (S) contents from 50 to 900 μg g–1. The total flux was enlarged from 7.96 to 37.61 kg m–2 h–1 with temperature increasing from 50 to 90°C. The membrane’s enrichments factor for thiophene were about 3.13 and dependent on the experimental conditions. The experimental results demonstrated that polyimide 6FDA-BDAF would be a potential membrane material for desulfurization and controlled release of the S-containing fertilizer.

Exploration of soil environmental characteristics governing soil microbial community structure and activity may improve our understanding of biogeochemical processes and soil quality. The impact of soil environmental characteristics especially organic carbon availability after 15-yr different organic and inorganic fertilizer inputs on soil bacterial community structure and functional metabolic diversity of soil microbial communities were evaluated in a 15-yr fertilizer experiment in Changping County, Beijing, China. The experiment was a wheat-maize rotation system which was established in 1991 including four different fertilizer treatments. These treatments included: a non-amended control (CK), a commonly used application rate of inorganic fertilizer treatment (NPK); a commonly used application rate of inorganic fertilizer with swine manure incorporated treatment (NPKM), and a commonly used application rate of inorganic fertilizer with maize straw incorporated treatment (NPKS). Denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA gene was used to determine the bacterial community structure and single carbon source utilization profiles were determined to characterize the microbial community functional metabolic diversity of different fertilizer treatments using Biolog Eco plates. The results indicated that long-term fertilized treatments significantly increased soil bacterial community structure compared to CK. The use of inorganic fertilizer with organic amendments incorporated for long term (NPKM, NPKS) significantly promoted soil bacterial structure than the application of inorganic fertilizer only (NPK), and NPKM treatment was the most important driver for increases in the soil microbial community richness (S) and structural diversity (H). Overall utilization of carbon sources by soil microbial communities (average well color development, AWCD) and microbial substrate utilization diversity and evenness indices (H’ and E) indicated that long-term inorganic fertilizer with organic amendments incorporated (NPKM, NPKS) could significantly stimulate soil microbial metabolic activity and functional diversity relative to CK, while no differences of them were found between NPKS and NPK treatments. Principal component analysis (PCA) based on carbon source utilization profiles also showed significant separation of soil microbial community under long-term fertilization regimes and NPKM treatment was significantly separated from the other three treatments primarily according to the higher microbial utilization of carbohydrates, carboxylic acids, polymers, phenolic compounds, and amino acid, while higher utilization of amines/amides differed soil microbial community in NPKS treatment from those in the other three treatments. Redundancy analysis (RDA) indicated that soil organic carbon (SOC) availability, especially soil microbial biomass carbon (Cmic) and Cmic/SOC ratio are the key factors of soil environmental characteristics contributing to the increase of both soil microbial community structure and functional metabolic diversity in the long-term fertilization trial. Our results showed that long-term inorganic fertilizer and swine manure application could significantly improve soil bacterial community structure and soil microbial metabolic activity through the increases in SOC availability, which could provide insights into the sustainable management of China’s soil resource.

As one of the staple food crops, rice (Oryza sativa L.) is widely cultivated across China, which plays a critical role in guaranteeing national food security. Most previous studies on grain yield or/and nitrogen use efficiency (NUE) of rice in China often involved site-specific field experiments, or small regions with insufficient data, which limited the representation for the current rice production regions. In this study, a database covering a wide range of climate conditions, soil types and field managements across China, was developed to estimate rice grain yield and NUE in various rice production regions in China and to evaluate the relationships between N rates and grain yield, NUE. According to the database for rice, the values of grain yield, plant N accumulation, N harvest index (HIN), indigenous N supply (INS), internal N efficiency (IEN), reciprocal internal N efficiency (RIEN), agronomic N use efficiency (AEN), partial N factor productivity (PEPN), physiological N efficiency (PEN), and recover efficiency of applied N (REN) averaged 7.69 t ha–1, 152 kg ha–1, 0.64 kg kg–1, 94.1 kg kg–1, 53.9 kg kg–1, 1.98 kg kg–1, 12.6 kg kg–1, 48.6 kg kg–1, 33.8 kg kg–1, and 39.3%, respectively. However, the corresponding values all varied tremendously with large variation. Rice planting regions and N rates had significant influence on grain yield, N uptake and NUE values. Considering all observations, N rates of 200 to 250 kg ha–1 commonly achieved higher rice grain yield compared to less than 200 kg N ha–1 and more than 250 kg N ha–1 at most rice planting regions. At N rates of 200 to 250 kg ha–1, significant positive linear relationships were observed between rice grain yield and AEN, PEN, REN, IEN, and PFPN, and 46.49, 24.64, 7.94, 17.84, and 88.24% of the variation in AEN, PEN, REN, IEN, and PFPN could be explained by grain yield, respectively. In conclusion, in a reasonable range of N application, an increase in grain yield can be achieved accompanying by an acceptable NUE.

The aim of drip fertigation is synchronising the application of water and nutrients with crop requirements, and maintaining the proper concentration and distribution of nutrient and water in the soil. The wetting patterns and nutrient distributions under drip fertigation have been proved to be closely related to the fertigation strategies. In order to find out the critical factors that affect the nutrient distribution under different drip fertigaiton strategies, a computer simulation model HYDRUS2D/3D was used to simulate the water and nitrate distribution for various fertigation strategies from a surface point source. Simulation results were compared with the observed ones from our previous studies. A 15° wedge-shaped plexiglass container was used in our experiment to represent one-twenty-fourth of the complete cylinder. The height of container is 40 cm, and the radius is 41 cm. The ammonium nitrate solution was added through a no. 7 needle connected to a Mariotte tube with a flexible hose. The soil water content, nitrate and ammonium concentrations were measured. The comparison of simulated and observed data demonstrated that the model performed reliably. The numerical analysis for various fertigation strategies from a surface point source showed that: (1) The total amount of irrigation water, the concentration of the fertilizer solution and the amount of pure water used to flush the pipeline after fertilizer solution application are the three critical factors influencing the distribution of water and fertilizer nitrogen in the soil. (2) The fresh water irrigation duration prior to fertigation has no obvious effect on nitrate distribution. The longer flushing time period after fertigation resulted in nitrate accumulation closer to the wetting front. From the point of avoiding the possibility of nitrate loss from the root zone, we recommended that the flushing time period should be as shorter as possible. (3) For a given amount of fertilizer, higher concentration of the fertilizer applied solution reduces the potential of nitrate leaching in drip irrigation system. While, lower concentration of the fertilizer solution resulted in an uniform distribution of nitrate band closer to the wetted front.

The whole-plant morphology, leaf ultrastructure, photosynthesis as well as enzyme activities of two tomato cultivars (Meifen-2 and Hongsheng) to differential light availabilities (450-500 μmol m-2 s-1, 75-100 μmol m-2 s-1) were examined in controlled environment. The results showed that the plant biomass and root/shoot ratio decreased and the specific leaf area increased significantly under the low light condition. There was a significant increase in malondialdehyde (MDA) concentration, superoxide dismutase (SOD) and peroxidase (POD) activities and decrease in soluble sugar and protein contents in LL-grown plants. For both cultivars, downregulation of photosynthesis and electron transport components were observed in LL-grown plants, the inhibition of the photosynthesis under the LL condition could be partially explained by the decrease of stomata density and by the changes of chloroplast.