Oceanic dimethylsulfide: production during zooplankton grazing on phytoplankton

About half the biogenic sulfur flux to the earth's atmosphere each year arises from the oceans. Dimethylsulfide (DMS), which constitutes about 90% of this marine sulfur flux, is presumed to originate from the decomposition of dimethylsulfoniopropionate produced by marine organisms, particularly phytoplankton. The rate of DMS release by phytoplankton is greatly increased when the phytoplankton are subjected to grazing by zooplankton. DMS production associated with such grazing may be the major mechanism of DMS production in many marine settings.     

Pollen influx and volcanic ash

Pollen influx can be used to estimate the duration of short-term depositional events. When applied to volcanic ashes, it may also provide information on the season and ecological effects of ashfall. In our initial application of the method to volcanic ashes from Lost Trail Pass, Bitterroot Mountains, Montana, we have illustrated that (i) two falls of Glacier Peak ash, which occurred about 11,250 (14)C years ago, were separated by 10 to 25 years; and (ii) volcanic ash from a major eruption of Mount Mazama (about 6700 (14)C years ago) first fell in the autumn and 4.6 centimeters of ash was deposited before the following spring. We also believe there is a reasonable probability that (i) about 1 centimeter of ash fell during the following year and about 1.7 centimeters fell the year after; (ii) in all, the sporadic primary Mazama ashfall lasted for nearly 3 years; (iii) Mazama ash resulted in low lake productivity, as measured by the occurrence of Botryococcus and Pediastrum; (iv) Mazama ash, perhaps through a mulching effect, may have produced increased vigor and pollen production in some sagebrush steppe genera; and (v) as measured by the records of fossil pollen and acid-resistant algae, effects on the aquatic and terrestrial ecosystems were short-lived. With refinement of the methods and broader geographic application, pollen influx studies may prove valuable for separating the regional and chronological details of tephra attributed to Mazama, Glacier Peak, and other Cascade Range volcanoes.     

Evidence against hydrogen-based microbial ecosystems in basalt aquifers

It has been proposed that hydrogen produced from basalt-ground-water interactions may serve as an energy source that supports the existence of microorganisms in the deep subsurface on Earth and possibly on other planets. However, experiments demonstrated that hydrogen is not produced from basalt at an environmentally relevant, alkaline pH. Small amounts of hydrogen were produced at a lower pH in laboratory incubations, but even this hydrogen production was transitory. Furthermore, geochemical considerations suggest that previously reported rates of hydrogen production cannot be sustained over geologically significant time frames. These findings indicate that hydrogen production from basalt-ground-water interactions may not support microbial metabolism in the subsurface.     

蜂王浆产量与温湿度关系的研究

通过给蜂群施加环境控制措施不同,结果蜂箱内部的小气候环境有着本质差异试验采取5种环境控制水平,不同处理水平的蜂箱内部温度存在极显著差异(F>0.01),蜂箱内部湿度存在显著差异(F>0.05),蜂王浆产量存在极显著差异(F>0.01),王台接受率差异不明显(F>0.05),并且得出湿度与产浆量呈负相关、相关系数为-0.6,温度与产浆量呈正相关,相关系数为 0.03.最后得出在高温季节,只要给蜂群遮荫在副盖上不加湿垫,同时坚持坚巢门喂水,产浆效果最佳.凡在蜂群副盖加湿垫来降温增湿的处理产浆均不佳.这一结论与人们传统的感性经验截然相反,试验得出结论在生产实施简单易行,具有较大经济价值,采用此法每箱每年较传统方法多产王浆600g,少投入垫子2元,共计可增收节支92元,同时又减轻养蜂人员每天给垫子加水的体力劳动.     

菊欧氏杆菌细菌素的产生与质粒的关系

菊欧氏杆菌(Erwinia chrysanthemi)的菌株EchB3和EchR8,能产生广谱性的细菌素。对EchB3和EchR8,分别用吖啶橙、利福平、胸腺嘧啶饥饿以及高温作脱质粒处理能得到不产细菌素的去质粒菌株。不同方法提取质粒证明产细菌素的野生型菌株能在0.8％的琼脂糖凝胶上检测到分子量约为22kb的质粒带,而失去产细菌素活性的去质粒菌株则检测不到。因此认为菊欧氏杆菌细菌素的产生可能与质粒有关。     

芸薹属蔬菜自交不亲和性克服方法研究进展

芸薹属自交不亲和性较为普遍,花期自交则不能结籽或结籽率极低,在育种中影响种子产量。为了提高种子产量,综述了近年来克服甘蓝、大白菜和油菜自交不亲和的物理和化学方法,以为相关技术人员参考。     

微生物发酵法生产2,3-丁二醇瓶颈因素分析

2,3-丁二醇（2,3-Butanediol）是一种极具价值的化工原料和液体燃料,应用广泛。许多微生物都能代谢产生2,3-丁二醇,但产率有差异。本文着重从发酵菌株、代谢途径、发酵底物、发酵工艺以及分离提取方法等方面概述了微生物发酵法生产2,3-丁二醇的研究进展,并讨论了2,3-丁二醇发酵过程中存在的问题和瓶颈因素。指出应从选育理想菌株出发,并对2,3-丁二醇的生化代谢途径中不同酶的动力学进行针对性的研究,以廉价的发酵底物及高效节能的分离纯化工艺进行发酵工艺优化,在此基础上进一步对2,3-丁二醇的系列衍生物进行开发应用,以降低生产成本,提高2,3-丁二醇的产量。     

甘蓝显性核基因雄性不育与胞质雄性不育系的选育及制种

 利用甘蓝显性核基因雄性不育材料DGMS79-399-3(79-399-3Ms)和引进的CMSR3625等改良胞质雄性不育材料作不育源,以优良自交系作转育父本,育成了一批不育性稳定、生长发育正常、配合力好的雄性不育系,配制出中甘16等6个甘蓝新品种。用雄性不育系进行规模化制种,每667m2生产杂交种种子40～50kg。不育系亲本可在隔离网棚用蜜蜂授粉繁殖,成本较低。杂交率比用自交不亲和系制种的高5%～8%。     

Solar neutrino production of long-lived isotopes and secular variations in the sun

Long-lived isotopes produced in the earth's crust by solar neutrinos may provide a method of probing secular variations in the rate of energy production in the sun's core. Only one isotope, calcium-41, appears to be suitable from the dual stand-points of reliable nuclear physics and manageable backgrounds. The proposed measurement also may be interesting in view of recent evidence for neutrino oscillations.     

脱毒马铃薯原原种多次收获效益与技术

生产脱毒马铃薯原原种采用稀植培育壮苗,每株最大薯块达3～4g时,及时收获,将植株重新定植,可使试管苗结出更多的微型薯,一般20d左右可进行2次收获,以后还可进行1～2次收获,大大地提高了试管苗的单株结薯率,减少试管苗的用量,降低生产成本64%左右.     

酸性木聚糖酶产生菌株的筛选和酶学性质分析

【目的】从自然环境筛选出可用于饲料工业加工用途的酸性木聚糖酶产生菌株。【方法】通过富集培养定向筛选技术,从土壤中分离获得18株产木聚糖酶菌株,挑选其中5株进行摇瓶发酵。对产酶最高的菌株S8-3进行初步鉴定,同时分析该菌株产生的木聚糖酶的酶学性质。【结果】经初步鉴定该菌株为黑曲霉(Aspergillus niger);该菌株发酵液的木聚糖酶活性高达628.43 U•mL-1;木聚糖酶的最适作用温度为45℃,最适pH为4.5,在70℃保温30 min后酶活力仍为60%以上,在 pH 3.0—7.0内稳定性较好。【结论】预期该菌株产的木聚糖酶具有用于饲料添加剂的潜力。     

葡萄及其制品中真菌毒素研究进展

葡萄在生产、贮藏和加工过程中,受环境条件的影响可能受到真菌的污染,进而产生不同的真菌毒素,影响葡萄及其制品的质量安全,给人类健康带来安全风险。有关葡萄及其制品中真菌毒素的研究,多集中在欧美等葡萄产区国家,我国在这方面研究以及相关的文献报道还比较少。本文系统分析了污染葡萄及其制品的真菌类型、污染条件以及产生真菌毒素的种类和含量;通过真菌毒素产生环境的介绍,提出了防治真菌毒素污染的控制手段,特别是真菌毒素分子生物学的深入研究,在区分真菌毒素种类和制定真菌毒素污染的控制技术方面可有效提供技术支撑。比较各国真菌毒素检测方法的研究,发现我国在研究水果及其制品中真菌毒素的检测方法、制定标准和真菌毒素在水果及其制品中的最大残留限量标准方面都存在不足。最后,提出了我国开展真菌毒素在葡萄及其制品中的研究方向。     

Inverse meta-modelling to estimate soil available water capacity at high spatial resolution across a farm

Geo-referenced information on crop production that is both spatially- and temporally-dense would be useful for management in precision agriculture (PA). Crop yield monitors provide spatially but not temporally dense information. Crop growth simulation modelling can provide temporal density, but traditionally fail on the spatial issue. The research described was motivated by the challenge of satisfying both the spatial and temporal data needs of PA. The methods presented depart from current crop modelling within PA by introducing meta-modelling in combination with inverse modelling to estimate site-specific soil properties. The soil properties are used to predict spatially- and temporally-dense crop yields. An inverse meta-model was derived from the agricultural production simulator (APSIM) using neural networks to estimate soil available water capacity (AWC) from available yield data. Maps of AWC with a resolution of 10 m were produced across a dryland grain farm in Australia. For certain years and fields, the estimates were useful for yield prediction with APSIM and multiple regression, whereas for others the results were disappointing. The estimates contain ‘implicit information’ about climate interactions with soil, crop and landscape that needs to be identified. Improvement of the meta-model with more AWC scenarios, more years of yield data, inclusion of additional variables and accounting for uncertainty are discussed. We concluded that it is worthwhile to pursue this approach as an efficient way of extracting soil physical information that exists within crop yield maps to create spatially- and temporally-dense datasets.     

Energy and Resources: A plan is outlined according to which solar and wind energy would supply Denmark's needs by the year 2050

Two possible futures for the industrial world may be distinguished: (i) Large amounts of low-cost energy become available and the more energy-intensive methods for extracting resources from lowergrade deposits continue to sustain industrial expansion until either the environmental impact becomes unacceptable or ultimate limits, such as climate disruptions, put an end to such growth. (ii) The cost of nonrenewable energy resources continue to rise, but a fixed amount of energy from continuous sources may be utilized at constant cost. In this case a lower production level may be set by the amount of energy that is available from renewable sources, and society may thus have to be reshaped with energy economization in focus. If it is possible to choose between these two alternatives, the choice should be based on a discussion of the pros and cons of each one, and in particular on the desirability of having to process an increasing fraction of the earth's crust in search of raw materials in order to maintain growth as long as possible. However, the availability, of the first option is far from certain and it thus seems reasonable to plan for the second alternative. I have tried to propose such a plan for a small, homogeneous geographical region, namely Denmark. The ceiling on the consumption of energy from continuous sources is chosen in accordance with the criterion of not having to convert a major part of the land area to energy-collecting systems. The proposed annual average energy consumption of 19 gigawatts by the year 2050 corresponds to solar energy collecting panels (in use only 50 percent of the time) with an area of roughly 180 square kilometers and a windmill swept area of about 150 square kilometers. These (vertical) areas constitute less than 1 percent of the total land area. The selection of solar or wind energy for different applications has been based on known technology and may be subject to adjustments. The project has been shown to be economically feasible according to estimates of the cost of various alternatives during the 25-year depreciation period adopted. However, the initial cost per energy unit produced is higher than that for most of the alternatives, so that action is not expected to be taken immediately as a result of purely private initiative. In a public economic evaluation, other factors must be considered in addition to the cost of energy per kilowatt-hour. At present, Denmark has over 10 percent of its labor force out of employment and a substantial deficit on its balance of payments, so that an early start on the solar and wind energy project, based on national industry, would have additional payoffs compared with energy systems based on imported technology or imported fuels. Several factories that are now being closed down as a result of the economic crisis could be adapted to the production of parts for solar or wind power systems, and the building industry, badly hit by unemployment, would receive legitimate work.     

现代温室番茄产量规律及其与环境因子的关系

对现代温室无土栽培的樱桃番茄和中果型番茄进行了3年3大茬的产量测定.结果表明,樱桃番茄年平均株高10 m左右,定植后70 d开始采收,年单株座果32~38层,每层15~30个果实,单果重12~15 g,每株年产果实3 kg左右,全年生长期340 d,采收期270~280 d,果实从开花至成熟需40~70 d,产量高峰分别在12月中旬至元月上旬和4月中旬至7月底.中果型番茄年平均株高6~8 m,定植后100 d左右开始采收,年单株座果22~25层,单果重150 g左右,每株年产果实10 kg左右,全年生长期340 d,采收期240~250 d,果实从开花至成熟70~100 d,产量高峰分别在1月和5~7月.年际间产量变化趋势基本一致,但总产量相差较大.年产量的60%~70%在4~7月份.由相关性分析可得,产量与温度呈显著至极显著的正相关,产量与光照呈正相关,产量与湿度呈负相关.温度与湿度呈显著至极显著的的负相关,温度与光照呈极显著的正相关,湿度与光照呈极显著的负相关.     

谷物真菌毒素的控制策略

谷物真菌毒素主要是作物在生长阶段或者谷物存放过程中受到真菌感染而由真菌产生的次生代谢产物.被真菌毒素污染的食物和饲料对人和动物具有严重的急慢性毒性,因此研究去除毒素污染的途径,将有效保障谷物类产品的食用安全.本文综述了控制毒素产生的策略,及各种真菌毒素去除方法,主要包括控制真菌生长以减少毒素的产生,利用物理去除、化学吸附方法去除毒素,以及通过化学分解或酶促降解毒素等,并分析了这些方法的应用前景.     

小麦中国春遗传背景的育种改良

 利用中国春与推广品种 (系 )杂交、回交进行小麦育种研究发现 :在与中国春的来源地有类似生态的育种条件下 ,中国春的适应性强、分蘖多、落黄好、多小花等优点能够用于小麦遗传改良 ,特别是在引入推广品种遗传背景时 ,中国春的“多小花”得到更好发育 ,导致穗粒数增多 ,可能是“增产资源”。而不利的遗传性状 ,如植株高、抽穗晚、易倒伏、株型差、千粒重低等能够被改进 ;单交组合的 1次回交和三交的方式 (中国春的血缘占 2 5 % )是育种效率最高的方式 ,其次是三交组合的 1次回交和单交组合的 2次回交 (中国春的血缘占 12 .5 % ) ,而单交 (中国春的血缘占 5 0 % )几乎不能获得理想的后代 ,是最差的方式     

4株癌细胞产生一氧化氨水平的观察

目的：观察体外培养不同癌细胞系的一氧化氮生（ＮＯ）成量。方法：用Ｇｒｉｅｓｓ试剂测定癌细胞系经２４ｈ培养后一氧化氮的生成量。结果：不同癌细胞的ＮＯ产量不同,其中ＨＬ－６０细胞的产量最高,Ｋ５６２细胞次之,Ｈｅｌａ细胞产量最低。结论：ＮＯ的产量与癌细胞的种类、分化程度可能有一定关系。     

Consumer attitudes to different pig production systems: a study from mainland China

In many countries consumers have shown an increasing interest to the way in which food products are being produced. This study investigates Chinese consumers’ attitudes towards different pig production systems by means of a conjoint analysis. While there has been a range of studies on Western consumers’ attitudes to various forms of food production, little is known about the level of Chinese consumers’ attitudes. A cross-sectional survey was carried out with 472 participants in 6 Chinese cities. Results indicate that Chinese consumers prefer industrial pig production systems, where traditional pig breeds are raised, over large-scale and small family farms. Farms with maximum attention to food safety, which furthermore can provide lean meat with consistent quality, are also preferred. Imported pig breeds and tasty but variable meat were rejected. A 3-cluster solution found that consumers from cluster 1 focus almost exclusively on the food safety aspect (food safety focused). Consumers from cluster 2 (indifferent) show weak overall attitudes to pig production systems in general. Cluster 3 (industrial production oriented) stands out by being very positive about industrial, large-size farms and consistent quality. From a Chinese consumer’s perspective, the industrial approach seems to represent values such as achievement and evolution, as well as quality and safety, since pig production is moving away from low-cost, low-quality, and low-safety family-scale systems. A complex set of rural and environmental development, quality aspects, and food safety measures are challenges that must be met by the stakeholders of pig production systems in China.