妃子笑荔枝树体镁素分布及累积特点

采用个体直接收获法,在采果后把10龄和3龄妃子笑荔枝树的根、茎、叶3个器官分成16～20个部位和组织,分别测定各个部位各个组织的生物量和镁浓度,并计算其累积量,以探明妃子笑荔枝树体内镁素在各个部位、组织中分布及累积特点,为荔枝镁营养研究及镁肥施用提供依据,结果如下：(1)镁浓度在不同组织和不同部位是不同的,在叶、皮部含量较高,在根颈、主根、茎枝木部含量较低;随着荔枝根系粗度增加,其镁浓度呈下降趋势;在同级枝干中,皮部镁含量显著高于木部;(2)10龄树老叶柄镁浓度显著高于3龄树,但其梢皮部和木部镁浓度则显著低于3龄树;(3)荔枝镁素累积在叶最多,其次为茎,根系镁累积量最少,叶镁素累积量占整株树镁素累积量50%以上(其中10龄树为50.7%,3龄树为62.0%)。10龄树镁累积量(62.0 g)是3龄树镁累积量(9.8 g)的6.3倍。     

淹涝胁迫和氮形态对苗期玉米营养特性的影响

采用砂培培养方法,比较研究两种水分条件和3种供氮形态处理对苗期玉米根、茎鞘、叶生物量干重及其氮、磷、钾含量及分配的影响。结果表明,非淹涝胁迫条件下铵硝态氮混合处理(AN)玉米生物量干重及氮、磷、钾累积量最高;淹涝胁迫条件下铵硝态氮混合处理(ANF)的叶片、总生物量以及硝态氮处理(NF)的根系、叶片和总生物量干重明显降低。淹涝胁迫降低3种氮形态处理叶片氮累积量,明显降低铵硝态氮混合处理和硝态氮处理植株氮、钾累积量,降低磷在铵硝态氮混合处理茎鞘、叶中的分配比例、磷在硝态氮处理根、叶中的分配比例以及钾在铵硝态氮混合处理茎鞘、叶中的分配比例。淹涝胁迫下铵态氮处理(AF)叶片含氮量、植株含钾量呈降低趋势;非淹涝胁迫下铵态氮处理(A)具有相对较高的植株氮、磷含量,且淹涝胁迫对氮、磷、钾在植株不同部位分配的影响相对较低。因此,本试验供应铵态氮苗期玉米具有相对较强的耐淹涝胁迫能力。     

亚麻干物质积累与氮磷钾吸收分配的研究

亚麻各生育期干物质积累是呈抛物线型，峰值在开花期，茎干物质随生育期进展逐渐增多，而根、叶的干物质逐渐减少。氮磷钾的积累量随着干物质增多而增加，峰值在快速生长期和开花期。植株各器官氮磷钾的含量，果＞叶＞根＞茎，亚麻茎的木质部，钾的含量占全株的７０％，而纤维只占３０％。     

亚麻干物质积累与氮磷钾吸收分配的研究

亚麻各生育期干物质积累是呈抛物线型，峰值在开花期，茎干物质随生育期进展逐渐增多，而根、叶的干物质逐渐减少。氮磷钾的积累量随着干物质增多而增加，峰值在快速生长期和开花期。植株各器官氮磷钾的含量，果〉叶〉根〉茎，亚麻茎的木质部，钾的含量占全株的７０％，而纤维只占３０％。     

喷施铁肥对不同基因型小麦产量和铁吸收的影响

为研究小麦的最佳喷施铁肥时期并筛选高铁基因型小麦,采用盆栽方法,以14个不同基因型小麦为材料,通过不同时期喷施铁肥,比较其对小麦产量和铁吸收的影响。结果表明,小麦拔节期叶面喷施铁肥可以增加籽粒产量、籽粒铁含量、籽粒铁累积量及占植株总铁积累量的比例。拔节期喷施铁肥提高了小麦根系的铁含量、累积量及根系铁占植株总铁累积量的比例。不同基因型小麦喷施铁肥时茎中的铁含量、铁累积量及占植株总铁累积量的比例均显著降低。小麦体内的铁主要储存在根系中,地上部的铁主要分布在叶片等营养器官中。与低铁基因型相比,高铁基因型小麦具有较低的籽粒产量和生物量,但籽粒产量占全株总生物量的比例却高于低铁基因型。无论是否喷施铁肥,高铁基因型小麦籽粒铁含量、铁累积量及占植株总铁累积量的比例均显著高于低铁基因型小麦。无论是否喷施铁肥,高铁基因型的根系生物量显著低于低铁基因型,但根系铁含量则显著高于低铁基因型,铁累积量则没有显著差异。拔节期喷施铁肥是促进不同基因型小麦生长、改善小麦铁营养状况的有效途径。     

香蕉幼苗对重金属Pb的吸收累积规律研究

研究重金属Pb在土壤-香蕉幼苗体系中的迁移分配规律。以沙质砖红壤为供试土壤，以香蕉幼苗为试验植物，采用实验室盆栽模拟试验进行研究。结果表明：Pb进入土壤后，从土壤向根系、茎、叶迁移，组织中Pb含量逐渐减少，表现为根系＞茎＞叶；不同Pb处理浓度对香蕉苗体内Pb富集效果有较大影响，随着Pb处理浓度的增加，香蕉苗各部位富集系数呈现先增后减的趋势，并在100 mg/kg处理时达到最大值；不同处理的香蕉苗各部位富集系数表现为根系＞茎＞叶。香蕉苗不同部位吸收累积重金属Pb大部分在根部，向茎和叶迁移的量较小。     

不同麻龄剑麻大中量营养元素分配及地上部养分累积特性的研究

对不同麻龄剑麻营养分配与累积特性进行研究.结果表明:不同麻龄剑麻各营养器官大中量元素的养分含量存在明显差异.其全株平均养分含量依次为:Ca＞K＞N＞Mg＞P.不同麻龄剑麻全株平均K/P比例逐渐降低,而全株平均Ga/Mg比例则随株龄增加而增大.全株平均养分含量的变化动态比例N∶P∶K∶Ca∶Mg=1∶0.10～0.14∶0.80～1.74∶2.31～3.60∶0.22～0.35.随着株龄的增加,剑麻叶和茎中的养分含量均有所下降,但各自峰值不同；根系中养分含量变幅不大,维持在各自平均水平.各营养元素在3龄麻时都形成1个快速积累期.     

苎麻对土壤中镉的耐受和积累效应研究

采用盆栽试验,研究了苎麻对镉的耐受性和积累现象。实验设计了镉浓度为0、50、100、200、300、400、500、600、700、800、900、1000、1200、1500mg·kg-1的Cd处理液,处理期间观察记录植株长势,后取样观察根系生长状况,分根、茎、叶测定植株体内的镉浓度。结果表明:低浓度(50-200mg·kg-1)时植株长势较好;浓度达到300mg·kg-1时植株出现毒害现象,表现为茎近根部出现褐色,并伴有腐烂、空心;浓度达到1200mg·kg-1时植株死亡。镉在苎麻体内各器官的分布为根>茎>叶;土壤有效Cd浓度较低时,苎麻对Cd的累积效应较强,较高浓度即由于毒害作用使其对Cd的累积效应下降。     

苎麻对土壤中镉的耐受和积累效应研究

采用盆栽试验,研究了苎麻对镉的耐受性和积累现象.实验设计了镉浓度为0、50、100、200、300、400、500、600、700、800、900、1000、1200、1500mg·kg-1的Cd处理液,处理期间观察记录植株长势,后取样观察根系生长状况,分根、茎、叶测定植株体内的镉浓度.结果表明低浓度(50-200 mg·kg-1)时植株长势较好;浓度达到300mg·kg-1时植株出现毒害现象,表现为茎近根部出现褐色,并伴有腐烂、空心;浓度达到1200 mg·kg-1时植株死亡.镉在苎麻体内各器官的分布为根＞茎＞叶;土壤有效Cd浓度较低时,苎麻对Cd的累积效应较强,较高浓度即由于毒害作用使其对Cd的累积效应下降.     

不同施肥水平下青蒿氮、磷、钾养分吸收特性

通过大田试验研究不同施肥水平下青蒿氮、磷、钾的吸收、累积与分配规律。选用当地主栽青蒿品种渝青 1 号为材料,设置高肥、中肥和低肥 3 个施肥水平。于苗期、分枝初期、分枝盛期及蕾期采集植株样本,分为根、茎、 枝和叶 4 部分,测定氮、磷、钾含量,计算青蒿主要生育期植株养分吸收、累积和分配情况。结果表明：青蒿对钾肥 的需求量最多,氮肥次之,磷肥最少。高肥和中肥处理整个生育期氮在不同器官中的含量为叶>枝>根>茎。低肥处理整 个生育期氮在不同器官中的含量为叶>枝>茎>根。高肥、中肥和低肥 3 个处理整个生育期磷在不同器官中的含量均为叶 >枝>茎>根。苗期和蕾期生长阶段高肥、中肥和低肥 3 个处理钾在不同器官中的含量均为叶>枝>茎>根,分枝初期和分 枝盛期生长阶段 3 个施肥处理钾在不同器官中的含量均为枝>叶>茎>根。不同施肥处理对养分积累趋势影响不大,但可 显著影响各器官在不同生育时期的养分积累量及分配比例。养分累积吸收量在生育前期较少,生育中后期急剧增加。 养分累积量以钾最多,氮次之,磷最少。青蒿中氮磷钾的吸收、累积与分配规律在不同施肥水平下存在差异,生产中 应根据土壤肥力和产量目标,采取合理施肥措施,达到经济施肥的目的。     

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.     

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.     

Recent Modifications of Chitosan for Adsorption Applications: A Critical and Systematic Review

Chitosan is considered to be one of the most promising and applicable materials in adsorption applications. The existence of amino and hydroxyl groups in its molecules contributes to many possible adsorption interactions between chitosan and pollutants (dyes, metals, ions, phenols, pharmaceuticals/drugs, pesticides, herbicides, etc.). These functional groups can help in establishing positions for modification. Based on the learning from previously published works in literature, researchers have achieved a modification of chitosan with a number of different functional groups. This work summarizes the published works of the last three years (2012–2014) regarding the modification reactions of chitosans (grafting, cross-linking, etc.) and their application to adsorption of different environmental pollutants (in liquid-phase).