滴灌下生物质改良材料对盐渍土水盐氮运移的调控效应

为探究生物质改良材料对滴灌盐渍土水、盐、肥运移过程的调控效应，采用土箱模拟试验，研究了水肥一体化滴灌条件下，生物炭和腐殖酸两种改良材料对盐渍土水、盐、氮运移和再分布过程及其时空分布特征的影响规律。结果表明：在滴灌条件下，盐渍土壤水盐的时空动态变化表现出明显的水分入渗驱动的盐分运移过程和蒸发扩散驱动的水盐再分布过程；铵态氮含量在时间上表现出先增大、后减小的变化趋势，在空间上的运移再分布特征较弱；硝态氮含量初始时空分布表现出与水盐相似的运移特征，受铵态氮硝化作用的多重影响，后期空间分布与铵态氮空间分布相似；生物炭通过提高土壤饱和导水率，增大了入渗阶段土壤水、盐、氮的运移速率和分布范围；腐殖酸通过提高土壤田间持水率增大了再分布过程土壤水、盐、氮的分布范围和强度，同时其对尿素的水解和硝化过程表现出更强的抑制效果。应用生物质改良材料在改变土壤物理性状进而调控滴灌土壤水盐运移的同时，还影响土壤氮素转化运移过程及其分布，这为水肥一体化滴灌盐渍农田的节水、控盐、减肥治理提供了理论基础。     

双季鲜食玉米/花生宽幅间作生态高效栽培技术

该文分析了双季鲜食玉米/花生宽幅间作生态高效栽培的意义,阐述了其栽培的技术要点,包括播前准备、播种与覆膜、田间管理、收获与晾晒、秸秆还田与残膜清除等.该技术主要适用于山东省小麦、玉米两熟轮作区及其他相似区域.     

规模化畜牧养殖对生态环境的破坏及防治

近年,畜牧养殖业蓬勃发展,过去的区域化散养已经基本不存在,养殖结构逐渐向集约化、一体化、规模化过渡,养殖规模也逐渐增大。养殖副产品肉、蛋、奶等极大满足了人们的生产生活,养殖中产生的尿液、粪污对生态环境造成极大影响。为促进规模化养殖实现绿色健康发展,该文分析规模化畜牧养殖对生态环境的破坏及防治措施。     

安徽南陵地区土壤养分丰缺状况研究

以安徽南陵地区土壤大量养分元素为主要研究对象,通过对区内土壤样品的采集与测试,统计分析土壤氮、碱解氮、磷、有效磷、氧化钾、速效钾等的含量特征,并对其分布特征加以研究,最终开展研究区土壤养分地球化学综合等级评价.结果表明,土壤氮和碱解氮在研究区内以丰富为主,且两者相关性较好,相关系数高达0.85,可能与土地利用类型有关;磷及有效磷在区内主要表现为较缺乏-缺乏,两者相关性较差,可能与磷在土壤中的存在形式及人为活动有关;氧化钾在区内分布主要表现为较丰富-中等-较缺乏3种,呈正态分布,孤峰河两侧分布差异明显,速效钾在区内零星分布,特征不明显;区内土壤养分地球化学综合评价结果以三级(中等)土壤为主,占研究区总面积的58.45％.     

Comparison of the microbial communities of alpacas and sheep fed diets with three different ratios of corn stalk to concentrate

The objective of this study was to investigate the characteristics of ruminal microbial communities of alpacas (Lama pacos) and sheep (Ovis aries) fed three diets with varying ratios of roughage (corn stalk) to concentrate, 3:7 (LS), 5:5 (MS) and 7:3 (HS). Six alpacas (one-year-old and weighing 29.5 ± 7.1 kg) and six sheep (one-year-old and weighing 27.9 ± 2.7 kg) were used in this study, in a replicated 3 × 3 Latin square experiment. Total protozoa concentration was determined under the microscope; total fungi and methanogens were assessed using quantitative polymerase chain reaction and expressed as a percentage of total bacterial 16S rRNA gene copies; bacterial communities were investigated by targeted 16S rRNA gene (V3–V4 region) sequencing. The percentage of fungi was significantly higher in alpacas than in sheep under the LS diet, while the concentration of protozoa was significantly lower in alpacas under HS, MS and LS diets. The alpha diversity including Shannon, Chao l and ACE indices of bacterial communities was higher in alpacas than in sheep, under the LS diet. A total of 299 genera belonging to 22 phyla were observed in the forestomach of alpaca and sheep, with Bacteroidetes and Firmicutes dominating both animal species. Phyla Armatimonadetes and Fusobacteria, as well as 64 genera, were detected only in alpacas, whereas phyla Acidobacteria and Nitrospira, as well as 44 genera, were found only in sheep. The abundance of cellulolytic bacteria, including Butyrivibrio and Pseudobutyrivibrio, was higher in alpacas than in sheep under all three diets. These differences in the forestomach microbial communities partly explained why alpacas displayed a higher poor-quality roughage digestibility, and a lower methane production. Results also revealed that the adverse effects of high-concentrate diets (70%) were lesser in alpacas than in sheep.     

Screening and Verification of Low Nitrogen Tolerant and Nitrogen Sensitive Cotton Germplasm

[Objective] The aim of this study is to evaluate nitrogen efficient cotton germplasms and improve nitrogen use efficiency. [Method] Eighty cotton germplasms were selected and evaluated in the hydroponic experiment under low (0.25 mmol·L^－1) and high (5 mmol·L^－1) nitrogen concentration. Different traits for screening were identified and nitrogen use efficiency types were classified. Field experiments were also performed for comparison and confirmation of the identified germplasms. [Result] The results showed that there were significant differences in the total plant dry matter, shoot nitrogen accumulation and nitrogen absorption efficiency in cotton germplasms at the two nitrogen levels. Based on coefficient of variation, principal component analysis and correlation, six traits including total plant dry matter, shoot dry matter, root dry matter, total nitrogen accumulation, shoot nitrogen accumulation and nitrogen absorption efficiency were used as screening indicators. According to the Heatmap clustering analysis and the nitrogen efficiency comprehensive index, two germplasms (Lu05R59 and CCRI 69) were identified as low nitrogen tolerant and nitrogen efficient, and two germplasms (Coker 201 and Xinluzhong 30) as low nitrogen sensitive and nitrogen inefficient. The results of field experiment were consistent with the results of the hydroponic culture at the seedling stage. [Conclusion] It was finally determined that Lu05R59 and CCRI 69 were the low nitrogen tolerant and nitrogen efficient germplasms, and Coker 201 and Xinluzhong 30 were low nitrogen sensitive and nitrogen inefficient germplasms. The results of these studies provide the possibility for screening and rapid identification of nitrogen use efficiency in cotton at the seedling stage, and provide the ideal materials and theoretical basis for further study of cotton nitrogen efficient.     

New Polyketides from the Antarctic Fungus Pseudogymnoascus sp. HSX2#-11

The species Pseudogymnoascus is known as a psychrophilic pathogenic fungus with a ubiquitous distribution in Antarctica. Meanwhile, the study of its secondary metabolites is infrequent. Systematic research of the metabolites of the fungus Pseudogymnoascus sp. HSX2#-11, guided by the method of molecular networking, led to the isolation of one novel polyketide, pseudophenone A (1), along with six known analogs (2–7). The structure of the new compound was elucidated by extensive spectroscopic investigation and single-crystal X-ray diffraction. Pseudophenone A (1) is a dimer of diphenyl ketone and diphenyl ether, and there is only one analog of 1 to the best of our knowledge. Compounds 1 and 2 exhibited antibacterial activities against a panel of strains. This is the first time to use molecular networking to study the metabolic profiles of Antarctica fungi.     

黄皮的生物学特性研究

通过本试验观察表明:黄皮[Clausena Lansium (Lour.)Skeels]的开花与温度有密切关系,温度高,开花过程短;温度低,开花过程长。花穗中的花轴增长速度也随温度升高而加快,花轴增长快,则花轴长,花穗大;反之,花轴增长速度慢,花轴短,花穗小。黄皮开花的顺序是从花穗基部第1—4个分枝开始,每个分枝则先从基部1—8个二次分枝首先开放。31℃是黄皮花粉萌发最适宜温度。在培养基中加入15—20％蔗糖或2.4—D,三十烷醇等生长调节物质,明显可提高黄皮花粉的萌发力。本试验对黄皮的物候期及植物学特性同时进行了研究。     

Alfalfa Phytoestrogen Content: Impact of Plant Maturity and Herbage Components

Legumes contain a range of non‐nutritional phytochemicals that may have health‐promoting effects in humans. In this study, we determined the concentrations of four phytoestrogens (coumestrol, apigenin, luteolin and quercetin) in field‐grown alfalfa (Medicago sativa L.). Differences between plants of different stages of maturity, between plant parts, and different canopy segments were assessed. The concentration of individual phytoestrogen in whole herbage varied between 15 and 225 μg g^?1 dry matter (DM) and was strongly affected by stage of maturity. Coumestrol and apigenin concentrations were highest at early vegetative stages, luteolin and quercetin at early vegetative and late flowering stages. All phytoestrogens were found in lowest concentrations at the early flowering stage (average 68 μg g^?1 DM); stage at which alfalfa is usually harvested when used as a forage source for animals. At vegetative stages, apigenin was the predominant phytoestrogen in herbage followed by coumestrol, the reverse being observed upon initiation of flowering; luteolin and quercetin were found at all stages in similarly lower concentrations. Concentrations of luteolin, quercetin and apigenin were 225, 410 and 690 % greater, respectively, in flowers than in leaves or stems; coumestrol concentration was similar between plant parts. In flowers and stems the predominant phytoestrogens were apigenin and quercetin, followed by coumestrol and luteolin. Similar concentrations (average 26 μg g^?1 DM) of each of the four phytoestrogens were found in leaves. Concentrations through the herbage canopy varied and were greatest at >60 cm from the soil surface for apigenin and coumestrol, but greatest at >60 and 0–20 cm for quercetin and at 0–20 cm for luteolin. The results suggest that if alfalfa is to be used as a source of phytoestrogens and is harvested for the production of herbal supplements or nutraceuticals, management will need to be adapted.