再生稻是指头季收获后，采用一定的栽培管理措施使稻茬上存活的休眠芽萌发成穗而再收获一季水稻的种植模式，具有省工、省种、省水、省药、省秧田和米质优等优点。边际效应是作物生产中的普遍现象，指边行植株由于具有更多的光照和养分，相比内行植株往往具有明显的产量优势。边际效应的挖掘与利用，对于构建水稻高产栽培模式具有重要意义。目前有关水稻边际效应的研究主要集中于常规稻作模式，而对再生稻边际效应的报道尚少。再生稻两季的边际效应有何差异，头季边行优势是否会促进再生季边际效应的发挥尚不清楚。因此，本研究在湖北省蕲春县开展为期两年的大田试验，于头季与再生季分别测定边行和中间行的产量及产量相关性状，旨在量化再生稻两季边际效应的差异以及头季边际效应对再生季边际效应的贡献。结果表明：再生稻在头季和再生季均存在明显的边际效应，且头季边际效应大于再生季。头季边际效应高达98.3%，得益于较多的有效穗数、每穗颖花数和干物质积累量。而再生季边际效应为60.9%，其中约一半由头季的边际效应所贡献。进一步分析发现，头季促进再生季边际效应发挥的原因在于头季收获时较高的稻桩干重和碳水化合物含量促进了再生季有效穗数和干物质积累量的增加。因此，增加稻桩的干物质和碳水化合物累积是提高再生季产量的有效措施。

多肽作为蛋白质中的功能活性片段，不仅可以提供人类生长发育所需的营养物质，而且与蛋白质相比，还具有独特的生理活性特征。生物活性肽具有巨大的发展潜力。食源性生物活性肽具有原料来源广泛、结构独特、高效安全等优点，发展前景广阔。本文综述了食源性生物活性肽的制备、功能特点，阐述了食源性生物活性肽的构效关系，并对食源性生物活性肽的开发应用前景进行了展望。本综述有助于加深对食源性生物活性肽的认识，为食品工业的进一步研究和应用提供一些有益的启示。

The aim of this study was to investigate the feasibility of stimulating ovarian follicle development in order to improve fertility in water buffalo cows by immunization against inhibin. The experiment was carried out in early summer (May) and included 24 multi-parity crossbred Murrah-Swamp buffaloes that were divided into immunized (n=11) and control (n=13) groups. Each immunized cow was administered with a 2-mL immunogen of mineral oil adjuvant containing 2 mg of recombinant inhibin α-subunit fusion protein. The controls were treated with the adjuvant only. All animals received Ovsynch protocol treatment, starting on the day of the antigen administration, and they were artificially inseminated upon behavioral estrus. As a result, all of the immunized buffaloes generated antibodies against inhibin during the experimental period and had higher plasma concentrations of follicle-stimulating hormone (FSH), activin, and estradiol (E2) related to estrous expression. A higher proportion of immunized animals expressed estrus behavior than did the controls (72% vs. 30%, P<0.05). On average, inhibin-immunized buffaloes had significantly more large follicles (≥9 mm in diameter) than the controls (mean±SEM; 1.2±0.1 vs. 0.84±0.1, respectively; P<0.05) and a slightly higher mean total number of follicles (≥2 mm; 11.4±0.7 vs. 9.0±1.1, respectively; P=0.09) and small (2–4 mm) follicles (8.81±0.6 vs. 6.84±1.0, respectively; P=0.12). A higher percentage of cows ovulated in the immunized group than in the control group (91% (10/11) vs. 54% (7/13), respectively; P<0.05). Moreover, inhibin-immunized cows had slightly larger corpus luteum (CL) than the controls 9 days after ovulation and significantly higher (P<0.01) post-ovulation peak plasma progesterone (P4) concentrations. Immunization against inhibin also marginally increased the conception rate 42 days after insemination (45.8% vs. 15.4%; P>0.05). These results demonstrate that immunization against inhibin, coupled with the treatment with the Ovsynch protocol, can constitute a new technique to increase fertility in water buffalo cows.

To make recycling utilization of organic materials produced in various agricultural systems, five kinds of organic materials were applied in a field test, including crop straw (CS), biogas residue (BR), mushroom residue (MR), wine residue (WR), pig manure (PM), with a mineral fertilizer (CF) and a no-fertilizer (CK) treatment as a control. Our objectives were: i) to quantify the effects of organic materials on soil C and N accumulation; ii) to evaluate the effects of organic materials on soil aggregate stability, along with the total organic carbon (TOC), and N in different aggregate fractions; and iii) to assess the relationships among the organic material components, soil C and N, and C, N in aggregate fractions. The trial was conducted in Wuqiao County, Hebei Province, China. The organic materials were incorporated at an equal rate of C, and combined with a mineral fertilizer in amounts of 150 kg N ha-1, 26 kg P ha-1 and 124 kg K ha-1 respectively during each crop season of a wheat-maize rotation system. The inputted C quantity of each organic material treatment was equivalent to the total amount of C contained in the crop straw harvested in CS treatement in the previous season. TOC, N, water-stable aggregates, and aggregate-associated TOC and N were investigated. The results showed that organic material incorporation increased soil aggregation and stabilization. On average, the soil macroaggregate proportion increased by 14%, the microaggregate proportion increased by 3%, and mean-weight diameter (MWD) increased by 20%. TOC content followed the order of PM>WR>MR>BR>CS>CK>CF; N content followed the order WR>PM>MR>BR>CS>CF>CK. No significant correlation was found between TOC, N, and the quality of organic material. Soil silt and clay particles contained the largest part of TOC, whereas the small macroaggregate fraction was the most sensitive to organic materials. Our results indicate that PM and WR exerted better effects on soil C and N accumulation, followed by MR and BR, suggesting that organic materials from ex situ farmland could promote soil quality more as compared to straw returned in situ.

It is predicted that the current atmospheric CO2 concentration will be doubled and global mean temperature will increase by 1.5-6°C by the end of this century. Although a number of studies have addressed the separate effects of CO2 and temperature on plant-insect interactions, few have concerned with their combined impacts. In the current study, a factorial experiment was carried out to examine the effect of a doubling CO2 concentration and a 3°C temperature increase on a complete generation of the brown planthopper (Nilaparvata lugens) on rice (Oryza sativa). Both elevated CO2 and temperature increased rice stem height and biomass of stem parts. Leaf chlorophyll content increased under elevated CO2, but only in ambient temperature treatment. Water content of stem parts was reduced under elevated temperature, but only when coupled with elevated CO2. Elevated CO2 alone increased biomass of root and elevated temperature alone enhanced leaf area and reduced ratio of root to stem parts. Brown planthopper (BPH) nymphal development was accelerated, and weight of and honeydew excretion by the F1 adults was reduced under elevated temperature only. Longevity of brachypterous females was affected by a significant interaction between CO2 and temperature. At elevated temperature, CO2 had no effect on female longevity, but at ambient temperature, the females lived shorter under elevated CO2. Female fecundity was higher at elevated than at ambient temperature and higher at elevated CO2 than at ambient CO2. These results indicate that the combined effects of elevated temperature and CO2 may enhance the brown planthopper population size.

Many studies have focused on various agricultural management measures to reduce agricultural nitrous oxide (N2O) emission. However, few studies have investigated soil N2O emissions in intercropping systems in the North China Plain. Thus, we conducted a field experiment to compare N2O emissions under monoculture and maize-legume intercropping systems. In 2010, five treatments, including monocultured maize (M), maize-peanut (MP), maize-alfalfa (MA), maize-soybean (MS), and maize-sweet clover (MSC) intercropping were designed to investigate this issue using the static chamber technique. In 2011, M, MP, and MS remained, and monocultured peanuts (P) and soybean (S) were added to the trial. The results showed that total production of N2O from different treatments ranged from (0.87±0.12) to (1.17±0.11) kg ha-1 in 2010, while those ranged from (3.35±0.30) to (9.10±2.09) kg ha-1 in 2011. MA and MSC had no significant effect on soil N2O production compared to that of M (P<0.05). Cumulative N2O emissions from MP in 2010 were significantly lower than those from M, but the result was the opposite in 2011 (P<0.05). MS significantly reduced soil N2O emissions by 25.55 and 48.84% in 2010 and 2011, respectively (P<0.05). Soil N2O emissions were significantly correlated with soil water content, soil temperature, nitrification potential, soil NH4 +, and soil NO3 - content (R2=0.160-0.764, P<0.01). A stepwise linear regression analysis indicated that soil N2O release was mainly controlled by the interaction between soil moisture and soil NO3 - content (R2=0.828, P<0.001). These results indicate that MS had a coincident effect on soil N2O flux and significantly reduced soil N2O production compared to that of M over two growing seasons.

A 2-yr field experiment was conducted on a calcareous alluvial soil with four summer maize intercropping systems at Shangzhuang Experiment Station (116.3°E, 39.9°N) in the North China Plain. The objective was to determine nitrate leaching from intercropping systems involving maize (Zea mays L.): sole maize (CK), maize + soybean (CST), maize + groundnut (CGT), maize+ ryegrass (CHM), and maize + alfalfa (CMX). Intercropping greatly reduced nitrate accumulation in the 100-200 cm soil layers compared with maize monoculture. Nitrate accumulation under intercropping systems decreased significantly at the 140-200 cm soil depth; the accumulation varied in the order CK>CST>CMX>CHM>CGT. However, compared to the CK treatment, nitrate leaching losses during the maize growing period were reduced by 20.9- 174.8 (CGT), 35.2-130.8 (CHM), 60.4-122.0 (CMX), and 30.6-82.4 kg ha-1 (CST). The results also suggested that intercropping is an effective way to reduce nitrogen leaching in fields with N fertilizer over-dose.