The hotter the weather,the greater the infestation of Portulaca oleracea: opportunistic life‐history traits in a serious weed

Portulaca oleracea, an r‐strategist, is one of the world's most troublesome weeds. During hot seasons, P. oleracea frequently becomes monodominant in choy sum (Brassica parachinensis) fields in Guangzhou city, southern China. Here, we studied the seasonal dynamics of P. oleracea's germinable soil seedbank, population density and above‐ground biomass in choy sum fields that had been cultivated continuously for several years. Using P. oleracea seeds collected from these fields, we tested seed dormancy, survival and germination, seedling growth and generation time. Portulaca oleracea occurred at high levels during the hot season, but its occurrence was low, and the germinable soil seedbank was much greater during the cold season. The weed's opportunistic characteristics allowed it to avoid freezing and to proliferate during optimal conditions. Portulaca oleracea's generation time was very flexible, as short as 31 days during the hot season, but longer than 100 days during the colder season. Seed dormancy tended to be shorter when the seeds were stored at a higher temperature. At a temperature of 35°C, both seed germination and seedling growth showed advantages over those of choy sum. Storage for one year at a temperature of ?20°C or burial in a paddy field did not significantly reduce P. oleracea seed germination. Nevertheless, seed storage at a temperature of 15°C and soil coverage of 0.5 cm on top of the seeds significantly constrained seed germination. ‘Stale seedbed’ and/or coverage of the surface with soil are recommended during the hot season. However, rotation of rice and upland crops is not an efficient method for managing Portulaca oleracea infestation.     

A novel screening method for rice allelopathic potential: the inhibitory‐circle method

Screening crop accessions for allelopathic activity is of paramount importance for crop allelopathy research. Previous bioassays often did not use a mixed culture of donor and target plants, did not use soil and were not conducted under natural conditions. In this study, we designed an inhibitory‐circle method in which a rice accession (donor plant) and Echinochloa crus‐galli (target plant) were cultured together in paddy soil under natural conditions. First, we determined that the highest allelopathic activity of allelopathic rice accession PI312777 was at the 5‐leaf stage, and the suitable distance of rice seedlings and E. crus‐galli was 12 cm apart. This method was then validated by a field test. A further 40 rice accessions were evaluated for allelopathic activity to E. crus‐galli using this method. Two rice accessions, PI312777 and Taichung Native 1, had highly allelopathic activity to E. crus‐galli (inhibitory rate > 50%), while another accession, Lemont, had non‐allelopathic activity. These experimental results were in accordance with previous studies using direct field experiments. The inhibitory‐circle method integrated three necessary conditions, that is donor and target plants grown together, with soil as the medium and under natural conditions for reliable results. The ‘inhibitory‐circle method’, which combined donor and target plants, soil medium and field conditions, can give reliable results in one step, compared with laboratory screening methods. Also, the ‘inhibitory‐circle method’ gave results in 30‐35 days, thereby substantially reducing the requirements for time, labour and cost.     

基于高斯随机扰动的潜在蒸散敏感性分析

旨在定量分析不同气象要素对潜在蒸散量敏感性大小的时空分布,以期为提高蒸散量计算精度提供依据。以1961年1月1日—2012年12月31日的日观测资料为基础,通过添加高斯分布随机扰动,计算各要素的敏感系数。研究表明：安徽全区年尺度上,日照时数和平均风速的敏感性最高,敏感系数分为0.1258和0.1089;月尺度上,4—9月蒸散量的主要敏感因素为日照时数,10月至次年3月的主要敏感因素为平均风速和实际水汽压。敏感性空间分布不均,淮河以北地区平均风速为主要敏感因素;淮河以南地区则仍是日照时数为主要敏感因素。     

水田灌排一体化系统的开发与应用

分析国内外农业灌溉和排水领域发展的研究现状和目前常见的灌排装置的特点,针对中国灌溉排水研究领域对节水灌溉、控制排水设施的迫切需求,提出了水田灌排一体化系统的设计方案.该系统能根据农作物不同时期对水位的需求,充分利用灌溉和降雨的水量,较为精确地控制水田的灌溉和排水水位,解决了原有灌排设备无法同时实现灌溉和排水自动控制的难题.实际应用结果表明,水田灌排一体化系统试验区和对照区相比,降雨量增加利用150 mm,降雨利用率提高21%,减少灌水量21%;水稻亩产量增加4.3%;提高肥料的利用效率,减少农业面源污染.该系统结构简单、操作方便,具有可观的经济、生态效益和广阔的应用前景.     

Isolation and Expression Analysis of CYP9A11 and Cytochrome P450 Reductase Gene in the Beet Armyworm (Lepidoptera: Noctuidae)

Cytochrome P450 monooxygenases (CYPs), as an enzyme superfamily, is widely distributed in organisms and plays a vital function in the metabolism of exogenous and endogenous compounds by interacting with its obligatory redox partner, CYP reductase (CPR). A novel CYP gene (CYP9A11) and CPR gene from the agricultural pest insect Spodoptera exigua were cloned and characterized. The complete cDNA sequences of SeCYP9A11 and SeCPR are 1,931 and 3,919 bp in length, respectively, and contain open reading frames of 1,593 and 2,070 nucleotides, respectively. Analysis of the putative protein sequences indicated that SeCYP9A11 contains a heme-binding domain and the unique characteristic sequence (SRFALCE) of the CYP9 family, in addition to a signal peptide and transmembrane segment at the N-terminal. Alignment analysis revealed that SeCYP9A11 shares the highest sequence similarity with CYP9A13 from Mamestra brassicae, which is 66.54%. The putative protein sequence of SeCPR has all of the classical CPR features, such as an N-terminal membrane anchor; three conserved domain flavin adenine dinucleotide (FAD), flavin mononucleotide (FMN), and nicotinamide adenine dinucleotide phosphate (NADPH) domain; and characteristic binding motifs. Phylogenetic analysis revealed that SeCPR shares the highest identity with HaCPR, which is 95.21%. The SeCYP9A11 and SeCPR genes were detected in the midgut, fat body, and cuticle tissues, and throughout all of the developmental stages of S. exigua. The mRNA levels of SeCYP9A11 and SeCPR decreased remarkably after exposure to plant secondary metabolites quercetin and tannin. The results regarding SeCYP9A11 and SeCPR genes in the current study provide foundation for the further study of S. exigua P450 system.     

茭草ISSR-PCR体系的优化

为了建立适用于茭草的ISSR-PCR反应体系,以湿地植物茭草基因组DNA为研究对象,筛选引物为UBC818,采用正交试验设计方法,建立了茭草ISSR-PCR反应体系和扩增程序。结果表明,在 25 μL反应体系中含有1×PCR缓冲液、250 μmol/L dNTP、2.0 mmol/L MgCl₂、0.5 μmol/L引物、1.0 U Taq DNA聚合酶和100 ng模板DNA最适用于茭草ISSR-PCR扩增。适宜的扩增程序为94℃ 5 min;94℃ 1 min;56℃ 45 s;72℃ 90 s;35个循环;72℃ 10 min;4℃保存。     

基于Android系统的温室环境监控APP研究与开发

针对大多数温室监控软件需要在固定的计算机终端前完成工作,使用范围固定,灵活性、实时性低等问题,研究开发了基于Android系统的移动温室监控APP,使得温室作业人员在移动设备上能够查看数据,根据监控数据采取相应措施,避免了人工管理温室无法实时掌握温室环境情况的问题。通过对温湿度和其他环境因子调控设施的远程调控,实现了节省人力、网络化和集约化的远程管理,构建适宜作物生长、繁育的良好生态环境。      

一种零件落料成形模设计

通过分析零件产品图确定产品的加工工艺,对落料成形模的关键零件进行设计,确定了模具的总体设计方案,对同类问题的解决提供了一种思路,具有一定的借鉴作用。      

Identification and characterization of a novel lymphocystis disease virus isolate from cultured grouper in China

Grouper Epinephelus spp. is one of the most important mariculture fish species in China and South-East Asian countries. The emerging viral diseases, evoked by iridovirus which belongs to genus Megalocytivirus and Ranavirus, have been well characterized in recent years. To date, few data on lymphocystis disease in grouper which caused by lymphocystis disease virus (LCDV) were described. Here, a novel LCDV isolate was identified and characterized. Based on the sequence of LCDV major capsid protein (MCP) and DNA polymerase gene, we found that the causative agents from different species of diseased groupers were the same one and herein were uniformly defined as grouper LCDV (GLCDV). Furthermore, H&E staining revealed that the nodules on the skin were composed of giant cells that contained inclusion bodies in the cytoplasm. Numerous virus particles with >210 nm in diameter and with hexagonal profiles were observed in the cytoplasm. In addition, phylogenetic analysis based on four iridovirus core genes, MCP, DNA polymerase, myristoylated membrane protein (MMP) and ribonucleotide reductase (RNR), consistently showed that GLCDV was mostly related to LCDV-C, followed by LCDV-1. Taken together, our data firstly provided the molecular evidence that GLCDV was a novel emerging iridovirus pathogen in grouper culture.     

Molecular cloning and expression of kidney‐type glutaminase from common carp (Cyprinus carpio) and its up‐regulation by glutamine in primary culture enterocyte

Glutaminase (GLS) is the key enzyme of glutamine (Gln) metabolism and utilization. In this study, a cDNA encoding GLS protein was identified from common carp Cyprinus carpio intestine. The open reading frame of GLS cDNA encodes a polypeptide of 595 amino acids, which shows a high similarity with its zebrafish Danio rerio counterpart. Bioinformatic analysis showed the protein belongs to kidney‐type GLS. The putative protein has glutaminase domain and ankyrin repeats domain, which are highly conserved among vertebrate orthologues. Real‐time quantitative PCR analysis revealed that the abundance of GLS mRNA was the highest in the white muscle, followed by the brain, eyeball and pituitary. Glutaminase was ubiquitously expressed in all intestinal segments of common carp. The activity of GLS did not distribute uniformly along the entire length of the intestine. In primary culture enterocyte, and the expression of GLS mRNA is up‐regulated quickly and effectively by Gln.