黑土不同耕层厚度对玉米根系形态空间分布及其产量的影响

在重建不同厚度黑土层的定位模拟试验区开展免耕玉米大豆轮作试验,设3个黑土耕层厚度(10、20和30 cm),探究不同耕层厚度对玉米生育期间的根系形态及其产量影响。研究表明,玉米产量对不同耕层厚度反应敏感,30 cm耕层厚度处理玉米产量最高,比20 cm和10 cm耕层厚度显著高12.5%和24.1%,且玉米根系分布对耕层厚度响应差异明显。30 cm耕层厚度显著影响玉米0～10 cm土层根重密度,对10～30 cm土层根重密度及不同土层根长密度和比根长影响不明显。     

黑土层厚度及心土培肥对大豆产量的影响

在盆栽试验条件下,以典型岗地白浆土土层结构为基础,通过改变黑土层的厚度研究了心土层对大豆产量的贡献;并通过混施磷肥和钙肥,研究了心土培肥的效果。结果表明:随着黑土厚度的增加,大豆株高和产量显著增加,白浆土心土对大豆产量的贡献很低,仅为4.7%;各心土培肥处理比心土混层增产9.7%～18.1%,比白浆土原状土壤增产16.0%～34.1%,土壤施磷后增加了Ca2-P、Ca8-P和Al-P的含量。因此,白浆土心混施钙磷肥对大豆有显著的增产效果。     

基于玉米-大豆轮作的不同施肥体系对大豆开花后根系形态及产量的影响

探讨玉米-大豆轮作条件下，降低生产成本、减少环境污染的大豆施肥模式，是目前东北大豆生产需要解决的技术问题。本研究基于建立的玉米-大豆轮作体系设置了5种施肥处理，分别为：T1：玉米施用化肥，大豆不施肥；T2：玉米施用化肥，大豆施用有机肥；T3：玉米施用化肥，大豆施用1/2量的化肥；T4：玉米施用化肥，大豆施用化肥；T5：玉米与大豆所需化肥总量一次性全部施入到玉米种植年份，大豆不施肥。分析了不同施肥模式对大豆不同生育期0~10、10~20、20~30cm土层深度内大豆根系干物质积累、根系形态特征时空变化以及与产量的关系。结果表明，经两个轮作周期，T2处理大豆产量最高为 2959kg·hm-2，比T4处理显著高出7.3%，产量提高主要体现在大豆的株高、主茎节数、单株荚数和单株粒数等性状的改善，而T1、T3、T5处理的大豆产量比T4处理显著低出15.4%，8.5%和5.0%。T2处理显著增加了大豆R6期0~10cm土层的根重密度，比T4处理显著高出42.3%，且与产量呈显著正相关，相关系数为0.655(p < 0.01)；T2处理也明显增加了大豆R1期0~10、10~20cm土层以及R6期20~30cm土层的根长密度，分别比T4处理显著高出25.3%、71.3%和27.6%，且与产量呈显著正相关，相关系数为0.692 (p < 0.01)。与T4处理相比，尽管T3处理显著增加了大豆R1期10~20、20~30cm土层的根重密度和R6期10~20cm土层的根长密度及根表面积密度，但均与产量呈显著负相关。T4处理只显著增加R1期单位体积的根表面积，而对大豆根平均直径和其它时期单位体积的根表面积的影响不大。因此，不同施肥措施影响大豆根系特征及其产量的关系问题比较复杂。施用有机肥可通过增加表土层根的重量以及深土层根的长度从而提高大豆的产量。因此在有机肥源供应充足的地区，玉米、大豆两区轮作基础上，玉米收获后秋施15t·hm-2有机肥，是提高大豆产量，降低生产成本，减轻化肥应用负面环境影响的替代措施。     

大豆植株不同冠层籽粒干物质积累动态及产量分布

研究了高产大豆品种新大豆1号、石大豆1号和黑农40在不同施氮水平(0、180、360 kg·hm-2)和不同密度(15、30万株·hm-2)处理下植株不同冠层籽粒干物质的积累动态及其产量分布.结果表明:大豆植株上、中、下层籽粒在形成过程中干物质积累的动态变化均极显著拟合于Logistic曲线方程;不同冠层中、下层籽粒到...     

密度与施肥对春大豆农艺性状及产量的影响

以吉育37为试材研究了种植密度和施肥量对大豆株高、叶面积指数、干物质积累和产量的影响.结果表明:随着密度的增加,株高、叶面积指数呈现上升的趋势,干物质积累呈现下降的趋势;随着施肥量的增加,株高、叶面积指数和干物质积累都呈现上升的趋势;随着密度的增加,大豆产量呈现先上升后下降的趋势;随着施肥量的增加,大豆产量呈现上升的趋势.在密度为19×104株/hm2、施肥量为200 kg/hm2时,产量最高.     

秸秆覆盖对黑土区大豆生长及产量构成因素的影响

为研究秸秆覆盖对黑土区土壤水热及大豆生长状况的影响，以垦丰16为试验材料，基于大田试验，分别设置秸秆表面覆盖(T1),0～10 cm土层秸秆还田覆盖(T2),10～20 cm土层秸秆还田覆盖(T3)和无秸秆覆盖(CK)4种处理。通过测定大豆生育期内的耕作层土壤温度及含水率，以及大豆株高、茎粗和叶面积等生长指标，对比分析不同秸秆覆盖处理对土壤水热、大豆生长及产量等性状的影响。结果表明：大豆生育期初T1处理0～10 cm土层含水率明显高于T2及T3处理；在10～20 cm差异逐渐缩小，20～30 cm土层差异变大；秸秆覆盖会影响播种初期的出苗率，而在播种10 d后T1处理的出苗情况最好；T2处理的大豆株高、茎粗、LAI及产量表现最佳。通过统计学分析不同秸秆覆盖之间的差异，秸秆覆盖具有一定的阻碍热量传递的作用，有利于土壤含水率的提高，对大豆生长状况、光合特性及产量产生影响，0～10 cm土层秸秆还田覆盖为最佳处理。     

大豆根系在土层中分布特点的研究

采用框架剖面法测定了大豆根系干重在草甸黑土和白浆土中的分布特点。大豆根系干重 85 %分布在水平方向的 0～ 12 .7cm ,获得高产的最适宜株行距为 12 .7× 12 .7cm ;大豆根系干重 85 %分布在垂直方向的 0～ 10cm ,呈现T型分布。根系在草甸黑土中水平分布与白浆土相似 ;但垂直方向的 0～ 10cm土层中 ,草甸黑土的根系干重高于白浆土     

不同土壤类型对玉米干物质积累动态及其分布的影响

研究结果表明:不同土壤类型对玉米干物质积累变化及分布影响较大。(1)砂姜黑土玉米干物质积累较多,且向雌穗、子粒中转运效率也高。(2)砂姜黑土玉米整个根系在土壤中分布较均,下扎较深,深层根量较多;而潮土玉米整个根系主要集中分布于0～20cm土层,下扎较浅,深层根量较少。(3)砂姜黑土玉米单产较高,较潮土玉米增产23.55%。     

滴水量对中熟大豆超高产田干物质积累和产量的影响

为探明超高产大豆的干物质积累和需水规律。田间研究了975(W1),1 575(W2),2 175(W3),2 775(W4)m3·hm-2共4种滴水量处理对中熟大豆品系10-4叶面积指数分布、干物质积累分配和产量的影响。结果表明:随着滴水量的增加,明显提高开花至成熟期间0~100 cm土层的含水量;增大主茎6~15节叶面积、群体中上部叶面积指数和群体光合势;显著增加总干物质积累量,W4和W3处理总干物质积累量分别较W1增加了44.8%和34.7%;增加植株6~16节位荚数、腔数和粒数,显著增加产量,W4和W3处理产量分别为6 404.7和6 082.6 kg·hm-2,分别较W1增产27.6%和21.2%。新疆伊宁地区大豆获得6 000.0 kg·hm-2产量,其生育期间田间适宜总滴水量为2 175~2 775 m3·hm-2,最大叶面积指数5.15~5.46,总干物质积累量13 500.0~14 514.0 kg·hm-2,经济系数为0.39。     

大豆干物质积累、分配规律的研究进展

大豆产量的形成主要取决于干物质的积累量及其在籽粒中的分配量,研究大豆及其群体干物质积累与分配的规律,对了解大豆产量形成具有重要意义.概述了大豆及其群体干物质积累、分配的一般规律,大豆干物质积累、分配与产量的关系,并介绍了大豆干物质积累、分配的主要影响因素以及高产大豆群体干物质积累、分配的特点的研究进展.以期为进一步深入进行大豆群体干物质积累、分配规律的研究提供理论依据和借鉴.     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.