紫花苜蓿花粉和胚珠与种子产量的关系*

 紫花苜蓿（Medicago sativa L.）是世界农牧业发展中极为重要的一种豆科牧草。通过对10个紫花苜蓿品种的花粉数量、胚珠数、花粉-胚珠比、花粉活力和种子产量进行了研究,结果表明紫花苜蓿每小花花粉数量（r = 0.89, P < 0.05）和胚珠数（r = 0.90, P <0.05）与种子产量呈显著正相关,每小花胚珠数与每荚种子数呈显著正相关（r = 0.89, P < 0.05）。各紫花苜蓿品种的花粉活力差异较大,变化范围为50.56%~80.76%。紫花苜蓿的花粉-胚珠比为 3 171.79～5 759.64 之间,该物种的繁育系统属于专性异交类型。     

Magnetic particles extracted from manganese nodules: suggested origin from stony and iron meteorites

On the basis of x-ray diffraction and electron microprobe data, spherical and ellipsoidal particles extracted from manganese nodules were divided into three groups. Group 1 particles are believed to be derived from iron meteorites, and Group 11 particles from stony meteorites. Group III particles are believed to be volcanic in origin.     

苎麻对农田土壤中汞、镉的吸收累积特征研究

为了评价非食用性经济植物苎麻对农田土壤中汞、镉的累积修复效果,本研究采集了46个种植于某汞矿区周边的汞、镉复合污染农田土壤的苎麻样品,分析了苎麻及对应土壤样品中汞、镉含量,计算了苎麻对汞、镉的累积系数和转运系数。结果表明:汞在苎麻根、秆、皮和叶中的含量分布为58.02~136.97、60.6~560.45、113.26~3 860.51、446.1~1 686.3μg·kg^-1;镉在苎麻根、秆、皮和叶中的含量分布为10.1~1 527.8、7.17~1 203.63、11.57~1 838.14、77.12~842.41μg·kg^-1。麻皮和麻叶中的汞含量明显高于根部;而镉较均匀分布在苎麻的根部、麻秆、麻皮及麻叶。汞和镉在对应土壤中含量分布为0.381~9.040 mg·kg^-1和0.131~7.814 mg·kg^-1。苎麻地上部对汞的累积系数范围为0.017~4.826,转运系数范围为0.583~22.595,苎麻地上部对镉的累积系数范围为0.011~3.725,转运系数范围为0.055~16.175。麻皮的汞累积系数明显高于根部和麻秆;而苎麻各部位的镉累积、转运系数无明显差别。土壤中的DOC含量上升会导致苎麻麻秆、麻皮中汞含量的下降,土壤pH的下降会促进苎麻的麻秆、麻皮两个部位对镉的吸收累积。     

白背天葵不同提取部位抗炎活性及机制研究

为研究白背天葵不同极性部位的抗炎效果及其机制,采用LPS诱导巨噬细胞RAW264.7建立炎症模型。Griess法检测白背天葵不同极性部位对LPS诱导的RAW264.7细胞释放NO的影响;ELISA法测定细胞分泌TNF-α,IL-1β,IL-6及PGE2的含量;运用Western blot检测不同极性部位对LPS诱导的RAW264.7细胞核内NF-κB p65蛋白表达的影响。结果表明,白背天葵各极性部位均能不同程度地抑制LPS诱导的NO、TNF-α、IL-1β和IL-6的过量分泌和细胞核内NF-κB p65的蛋白表达,白背天葵正丁醇相和乙酸乙酯相能显著抑制LPS诱导的PGE2的分泌。综上,白背天葵的抗炎作用可能是通过抑制NF-κB p65通路活化,进而抑制炎症介质和促炎细胞因子的合成和释放来实现的。     

Prediction model for mercury transfer from soil to corn grain and its cross-species extrapolation

In this study the transfer characteristics of mercury(Hg) from a wide range of Chinese soils to corn grain(cultivar Zhengdan 958) were investigated. Prediction models were developed for determining the Hg bioconcentration factor(BCF) of Zhengdan 958 from soil, including the soil properties, such as p H, organic matter(OM) concentration, cation exchange capacity(CEC), total nitrogen concentration(TN), total phosphorus concentration(TP), total potassium concentration(TK), and total Hg concentration(THg), using multiple stepwise regression analysis. These prediction models were applied to other non-model corn cultivars using a cross-species extrapolation approach. The results indicated that the soil p H was the most important factor associated with the transfer of Hg from soil to corn grain. Hg bioaccumulation in corn grain increased with the decreasing p H. No significant differences were found between two prediction models derived from different rates of Hg applied to the soil as HgCl_2. The prediction models established in this study can be applied to other non-model corn cultivars and are useful for predicting Hg bioconcentration in corn grain and assessing the ecological risk of Hg in different soils.     

磷对稻田甲烷排放的影响及其可能机制

目前关于磷对稻田甲烷排放的影响研究较少,为此,本文检索了已发表的磷对稻田甲烷排放的相关文章,并对文献数据进行了再挖掘分析,总结归纳了磷对甲烷产生和氧化的可能影响,并对未来需要进一步探究的问题进行了讨论。分析发现磷对稻田甲烷排放的调控主要受种植系统和其他施肥情况的影响,一季中稻下大都表现为磷肥施用降低甲烷排放,降幅受其他土壤养分情况影响而不同。磷通过影响水稻根系及其分泌物进而影响土壤碳的有效性,直接影响土壤磷的有效性,并改变土壤产甲烷菌和甲烷氧化菌的丰度和群落组成来调控甲烷的产生及氧化过程,最终影响甲烷的排放。     

洞庭湖平原冲积性菜园土无机氮形态及剖面分布

采用野外调查取样和室内分析相结合的方法,研究了洞庭湖平原冲积性菜园土无机氮形态及剖面分布规律.结果表明,耕层土壤全N平均含量为1.25g/kg,变化范围为0.65～1.67g/kg,变异系数为15.54%;固定态铵平均含量为295mg/kg,占土壤全氮含量的23.2%,NO3--N和NH4+-N平均含量分别为46.00、1.91mg/kg.土壤全N、铵态氮、固定态铵含量在0～80cm土层中随剖面深度的增加而降低,硝态氮的剖面分布表现有淋洗下移的现象.     

Studies on Single Cell Culture in vitro in Wheat--The variation of grain protein content and its fractions from regenerated plants

On the basis of previous studies dealing with the variation of major agronomic and yield characteristics of regenerated plants derived from single cell culture in vitro of common wheat (Triticum aestivum L.Cultivar NE 7742),the grain protein content and its fractions from regenerated plants with stable agronomic characteristics were studied from 1992 to 1995.The results showed that the variation of grain protein content and its fractions in somaclones from single cell culture in vitro were very significant and the range was very wide (11.53-17.70%).Several types of variation were found in the studies,espercially the type with higher protein content than that of cultivar NE 7742(non-culture parent).Among them.-20.69% of lines the grain protein content was significantly higher than that of NE 7742 and combined with high yielding potential.The tendency of variation of the four protein fractions showed that the variation of albumin was not obvious and maintained the same level as NE7742,the content of gliadin increased in some somaclones and decreased in others.However,the percentages both globulin and glutenin tended to increase.The variation of total amount of structural protein and the ratio between globulin and glutenin tended to increase.the variation of total amount of structural protein and the ratio between globulin and albumm was mainly influenced by globulin under the condition of culture in vitro.The variation of total amount of storage protein and the ratio between gliadin and glutenin was mainly by glutenin.The results mentioned above bemonstrated that the induction and screening of somaclonal variation could be an effective way in wheat improvement in combining high protein content with high yield.     

滴灌追氮管理对宿根蔗田土壤氮组分及N2O排放的影响

【目的】研究滴灌追氮管理对宿根蔗田土壤氮组分和N₂O排放的影响,揭示影响土壤N₂O通量的土壤因子。【方法】以二代宿根蔗Saccharum officinarum为研究对象,在移动防雨棚内进行2个滴灌灌水量[田间持水量的70%～80%(W0.8)和田间持水量的80%～90%(W0.9)]及3种滴灌追氮比例(等氮量250 kg·hm^-2,其中,N0为用作追肥的氮肥全部施用到土壤中,N5为50%土施追氮、50%用滴灌系统施用,N7为30%土施追氮、70%滴灌追氮)的田间试验。在甘蔗生长的各个时期测定蔗田土壤N₂O通量、pH和氮组分含量,并分析土壤N₂O通量与土壤pH和氮组分含量的关系。【结果】土壤N₂O通量在施用氮肥和灌水后2 d较高,其中,分蘖后期和成熟期W0.9N5处理的土壤N₂O通量显著低于其他处理。W0.9条件下,分蘖后期N5处理的土壤N₂O累积排放量分别比N0和N7低47.3%和11.8%,伸长后期N5处理的...     

A comparison of the biological activities of ethyl acetate fractions from the stems and leaves of Penthorum chinense Pursh

Penthorum chinense Pursh (PCP) is a popular traditional medicinal plant in China, widely used for the treatment of a variety of liver diseases. Although it has been long recognized that the main active elements of PCP are contained in ethyl acetate fraction (EAF), little is known so far in terms of the relative effectiveness of EAF derived from the stems versus leaves of this plant. In the current study, we prepared EAF by reflux extraction and sequential extraction from the stems (SEAF) and leaves (LEAF) of PCP and tested their hepatoprotective efficacies. The extract rates and flavonoid contents of LEAF were higher than those of SEAF. EAFs (>50 μg·mL⁻¹) prevented lipid accumulation in cells and protected against lipotoxicity injury when the concentration exceeded 25 μg·mL⁻¹. More than 95% free radicals released by 2,2-diphenyl-1-picrylhydrazyl (DPPH) were eliminated by 25 μg·mL⁻¹ SEAF and 50 μg·mL⁻¹ LEAF, respectively. Further, EAFs (25 μg·mL⁻¹) also showed protective antioxidant effects, with the activity of LEAF being significantly higher than that of SEAF. EAFs (10 mg·mL⁻¹) also showed similar unspecific bacteriostatic activity. In comparison with SEAF, LEAF contained more flavonoids and had a higher anti-oxidation capability and for these reasons we suggest it should be better for clinical use.     

江苏省密切产学研合作的实践与启示

产学研合作是江苏创建创新型省份的重要手段.研究分析了近年来江苏省产学研合作的模式与成效,指出江苏省产学研合作的实践对产学研合作较为落后地区的启示意义.     

Moving away from technocratic framing: agroecology and food sovereignty as possible alternatives to alleviate rural malnutrition in Bangladesh

Bangladesh continues to experience stubbornly high levels of rural malnutrition amid steady economic growth and poverty reduction. The policy response to tackling malnutrition shows an overwhelmingly technocratic bias, which depoliticizes the broader question of how the agro-food regime is structured. Taking an agrarian and human rights-based approach, this paper argues that rural malnutrition must be analyzed as symptomatic of a deepening agrarian crisis in which the obsession with productivity increases and commercialization overrides people’s democratic right to culturally appropriate, good, nutritious food. Using qualitative insights from a case study of three villages, this research illustrates how agricultural modernization and commercialization reproduce rural malnutrition by degrading local biodiversity and the rural poor’s access to nutrient-rich diets. In so doing, it undermines the official discourse’s simplistic and literal reading of malnutrition as a pathological health condition resulting from the mere absence of certain micronutrients in the human body, and thus questions the adequacy of the proposed solutions. Instead, this research suggests that solving malnutrition in large part involves facilitating the rural poor’s access to nutritious diets through democratizing and reorganizing the agriculture sector in a manner that is eco-friendly and unconstrained by market imperatives. It cautiously advances agroecology and food sovereignty as possible alternatives, while recognizing that overcoming the challenges agrarian class conflict, gender disparity and urban–rural divide pose would not be easy.     

RAPD和SSR标记对不同样点(产地)水稻品种分析的比较

选用 10个随机寡核苷酸引物和 10对微卫星引物 ,分别对 5个水稻品种不同产地的样本进行RAPD和SSR标记分析。结果表明 ,SSR标记分析具有稳定可靠的特点 ,可以直接应用特征性标记去进行种性的区别与鉴定研究。而RAPD标记分析 ,虽然简单方便 ,但就整体而言 ,重复性与可靠性显得明显不足。然而 ,通过大量的筛选和严格的验证 ,也是能够发现稳定性和重复性较好的标记用于种性的区别与鉴定的工作中     

Cretaceous sauropods from the sahara and the uneven rate of skeletal evolution among dinosaurs

Lower Cretaceous fossils from central Niger document the succession of sauropod dinosaurs on Africa as it drifted into geographic isolation. A new broad-toothed genus of Neocomian age ( approximately 135 million years ago) shows few of the specializations of other Cretaceous sauropods. A new small-bodied sauropod of Aptian-Albian age ( approximately 110 million years ago), in contrast, reveals the highly modified cranial form of rebbachisaurid diplodocoids. Rates of skeletal change in sauropods and other major groups of dinosaurs are estimated quantitatively and shown to be highly variable.     

不同基因型玉米幼胚愈伤诱导及植株再生研究

本研究通过对不同基因型的玉米幼胚进行愈伤组织诱导实验,从49份玉米自交系材料中筛选出了5个胚性愈伤组织诱导率较高的自交系,其中,K6-64,K6-39,DL283-1诱导出的Ⅱ型胚性愈伤,具有很强的长期继代能力和再生能力,适宜作为转化受体材料进行遗传转化研究。对玉米幼胚在离体培养过程中影响因素进行了研究,1.5～2.0 mg/L 2,4-D能够较好的诱导玉米幼胚产生胚性愈伤组织。一定浓度的6-BA和KT都能够较好的促进玉米愈伤组织分化。     

关于中国征地法律冲突引起的问题及对策探讨

从中国现行征地存在的一些法律冲突入手,导出了这些法律冲突所引起的问题,即公共利益范围的扩大化。然后,分析了中国征地实践中存在的两种征地现象:公共利益性质征地和非公共利益性质征地,并举出案例加以分析和说明。最后,针对公共利益范围的扩大化问题,提出科学合理的界定公共利益这一相应策略。     

澳大利亚与黄淮小麦品种的SSR遗传多样性比较

利用小麦21条染色体上的21个SSR标记,对16个澳大利亚小麦品种和21个黄淮小麦品种的遗传多样性进行了比较。结果表明,澳大利亚小麦品种共检出96个等位位点,平均为4.57个,平均遗传距离0.222 8。黄淮小麦品种共检测到86个等位位点,平均为4.1个,平均遗传距离0.173 1。电泳和聚类分析结果表明,澳大利亚小麦和黄淮小麦品种分别有10个和9个相对特异位点,携带相对特异位点的品种分别为6个和7个,75%以上地域来源相同的品种聚于相应的组。     

北疆棉区棉花黄萎病菌培养性状及致病力分化

【目的】 研究新疆北疆棉区棉花黄萎病菌的致病类型、培养特性及致病力分化。【方法】 从北疆主要植棉区采集棉花黄萎病病株,利用大丽轮枝菌特异引物VDS-F/VDS-R、落叶型菌系特异性引物D1/D2、非落叶型菌系特异性引物ND1/ND2对所有分离的菌株进行检测;根据落叶型和非落叶型菌株在单个条田中所占的比例对田间地块进行分析;选取18个代表菌株对其在PDA上的培养特性及对棉花的致病力分析。【结果】 从北疆棉田病株上分离到644个大丽轮枝菌菌株,67.5%的菌株为落叶型菌系,27.8%为非落叶型菌系,4.7%菌株不能归类,供试菌株的致病类型存在分化,其中以落叶型菌系为主要致病类型。对田间地块进行分析,单一落叶型菌株发生的地块最多,其次是落叶型和非落叶型菌株混合发生地块,田间以落叶型菌株为优势菌株的地块占70.1%,落叶型菌系为田间地块的主要致病类型。18个代表性菌株形成菌核型、菌丝型和中间型3种菌落类型,菌核型为主要的培养类型,并进一步分化形成3种不同的类型。对棉花感病品种的致病力进行测定,落叶型菌株引起的病指普遍高于非落叶型菌株引起的病指,非落叶型菌株中也有病指很高的菌株,北疆棉花黄萎病菌的致病力存在明显分化。【结论】 北疆棉田采集的棉花黄萎病菌,其致病类型、培养特性及致病力均存在明显分化。     

7株鳗鲡致病性气单胞菌毒力基因胞外产物及其活性比较

为探讨致病性气单胞菌的致病力与其胞外产物和毒力因子之间的关系,联合利用PCR、SDS-PAGE、平板扩散及分子进化等方法对7株鳗源气单胞菌的胞外毒力因子进行比较研究。结果显示,该7株致病菌所含有的胞外毒力基因(hly、aer、ast、act、alt、ahpA、epr和exu)在种类和数量上差异显著,其中hly可能是鳗源气单胞菌重要的致病因子;不同致病菌的胞外蛋白在种类和数量上都存在差异,其中分子质量约为50.7ku的蛋白,其分泌量高且在鳗源气单胞致病菌中较保守;该7株致病菌胞外产物均具有溶血、酪蛋白酶和卵磷脂酶活性,胞外产物活性与毒力基因的分布一致;胞外毒素基因hly和ahpA具有较高的属间保守性,而exu则具有较好的种间特异性。