放线菌剂使用方法对晚播冬小麦生长及光合性状的影响

为探究放线菌剂使用方法对晚播冬小麦生长及光合性状的影响，以长6990为供试小麦品种、娄彻氏链霉菌（D74）为供试菌剂，在大田设置T1（种子包衣+拔节期、灌浆期喷施D74菌剂）、T2（种子包衣+拔节期喷施D74菌剂，灌浆期喷施清水）、T3（种子包衣+拔节期、灌浆期喷施清水）、T4（种子不包衣+拔节期、灌浆期喷施D74菌剂）和CK（种子不包衣+拔节期、灌浆期喷施清水）5个处理（包衣中含有菌剂D74），比较分析了不同处理间小麦产量及其构成要素、表型性状、光合特性及干物质积累的差异。结果表明，放线菌剂处理下晚播小麦的产量较CK均不同程度提高，增产幅度为7.35%~25.00%，且不同处理的产量表现为T4>T1>T2>T3>CK，其中T1、T4处理与CK差异显著(P＜0.05)；不同处理间株高无显著差异(P>0.05)， T1和T4处理的穗长、穗粒数和千粒重显著高于CK，T2处理穗粒数和千粒重也较高。在光合性状中，放线菌剂处理主要影响晚播小麦灌浆后期的光合效率。花后28~35 d，T1、T4处理的旗叶净光合速率，T1~T4处理的旗叶叶绿素相对含量（SPAD）和氮含量，T1、T2和T4处理的叶面积指数均显著高于CK。放线菌剂使用后晚播小麦的花前干物质转运量及其对籽粒产量贡献率有所降低，但不同处理间差异不显著。T1、T2和T4处理的花后干物质的积累量较CK增加了37.93%、29.42%和50.92%；花后干物质积累对籽粒产量贡献率也有所提高，但不同处理间差异不显著。综合来看，放线菌剂能够有效增加晚播小麦的光合持续能力，延缓叶片衰老，促进花后干物质积累、穗部发育和籽粒灌浆，增加穗粒数和千粒重，进而提高产量，其中放线菌剂种子包衣效果不明显，叶面喷施放线菌剂效果较突出，拔节期和灌浆期叶面喷施放线菌剂的效果最佳。     

京科968的灌浆特征与产量性能分析

以京科968为材料, 采用春播、夏播2种播期, 设置45 000、60 000、75 000株/hm²共3种密度处理, 对其灌浆特征与产量性能进行分析。结果表明, 粒重与灌浆速率最大时的生长量(W_max)、最大灌浆速率(G_max)、活跃灌浆天数(P)呈极显著正相关, 与达到最大灌浆速率的天数(T_max)、灌浆起始势(R₀)呈显著或极显著负相关。平均叶面积指数、穗数、产量与密度呈正相关;平均净同化率、穗粒数、千粒重与密度呈负相关;平均叶面积指数与穗数与产量都呈极显著正相关。     

氮素追施对玉米花后光合特性和子粒灌浆特征的影响

为进一步挖掘东北黑土雨养农业区春玉米增产潜力,为合理施氮提供理论依据,以玉米品种富民985为试验材料进行田间试验。设置5种施氮方式,氮肥1次性施入(CK)、底肥40%+拔节期追施60%(T1)、底肥40%+拔节期追施20%+大喇叭口追施40%(T2)、底肥40%+拔节期追施15%+大喇叭口追施30%+灌浆期追施15%(T3)、底肥40%+拔节期追施10%+大喇叭口追施30%+灌浆期追施20%(T4),研究不同处理玉米花后穗位叶SPAD值、净光合速率(P_n)、磷酸烯醇式丙酮酸羧化酶活性(PEPc)及子粒容重和产量差异,利用Logistic方程拟合玉米灌浆过程。结果表明,T4处理子粒产量显著高于其他处理和对照。与氮肥1次性施入(CK)相比,T4处理玉米灌浆期穗位叶P_n和PEPc显著提高了42.8%和20.6%,玉米有效灌浆期延长13.7 d,到达最大灌浆速率时间延后2.4 d,子粒容重提高1.2%。在东北半湿润雨养农业区,按照底肥40%+拔节期追施10%+大喇叭口追施30%+灌浆期追施20%方式施用氮素(T4)可以获得更多光合产物,延长灌浆时间,增加子粒重量,提高玉米产量。     

外源MeJA对花后干旱胁迫下小麦光合特性的影响

为给外源茉莉酸甲酯(MeJA)在小麦抗旱栽培中的合理利用提供依据,以大面积推广的小麦品种周麦18为试验材料,用盆栽控水的方法模拟干旱胁迫,研究了外源MeJA对花后干旱胁迫下小麦光合特性的影响。结果表明,干旱胁迫显著降低了小麦旗叶叶绿素a、叶绿素b、叶黄素含量及气孔导度和蒸腾速率,提高了PSⅡ初始荧光(F_o)和非光化学淬灭系数(NPQ)及叶黄素循环组分(V+A+Z)含量和(A+Z)/(V+A+Z)值,导致光合速率（P_n）及PSⅡ潜在活性（F_v/F_o）、最大光化学效率（F_v/F_m）、实际光化学效率（Φ_PSⅡ）受到显著抑制,最终表现为叶片瞬时水分利用效率(WUE)和光能利用率(LUE)显著降低。干旱胁迫下喷施MeJA显著增加了叶黄素、β-胡萝卜素、(V+A+Z)含量及(A+Z)/(V+A+Z)值,从而使F_o和NPQ显著增大,缓解了干旱胁迫下强光对叶绿素产生的氧化破坏,而较低的叶绿素a/b也增强了小麦对弱光的利用效率。喷施MeJA能诱导叶片气孔适当关闭,减少了水分的散失,因而显著提高了灌浆中后期叶片P_n、F_v/F_o、F_v/F_m、Φ_PSⅡ,最终表现为WUE和LUE显著提高。这表明外源MeJA能增强小麦叶片光合系统在干旱胁迫下的稳定性,改善小麦光合作用。     

小麦淀粉合成关键酶基因和相关蛋白表达对不同施磷量的响应

为深入研究磷素在小麦淀粉产量和品质形成过程中的作用,以新疆冬小麦主栽品种新冬20号为试验材料,研究0 kg·hm^-2（CK）、105 kg·hm^-2（LP）和210 kg·hm^-2（HP）3种施磷（P₂O₅）量对小麦籽粒灌浆特性、淀粉合成关键酶(AGPase和GBSS)活性和基因表达、胚乳可溶性蛋白和淀粉粒结合蛋白含量及谱带特征、胚乳微观特性等的影响。结果表明,籽粒灌浆后期磷肥对粒重的促进作用逐渐增强;低磷（LP）条件下, agp1、 agp2、 gbss1、 gbss2基因表达量显著提高;3个处理下AGPase活性的变化趋势基本一致;籽粒灌浆中期（14～21 d）,低磷处理的GBSS活性显著高于CK;不同磷处理对淀粉粒结合蛋白和胚乳可溶性蛋白含量的影响显著,但对蛋白谱带特征的影响较弱。扫描电镜结果显示,不同磷处理的胚乳淀粉粒形态未发生明显变化;与CK和高磷（HP）处理相比,低磷处理下籽粒胚乳横断面蛋白基质较少,淀粉粒与蛋白质结合较疏松。说明常规施磷（低磷）条件下,淀粉合成关键酶基因（agp和gbss）相对表达量提高或酶活性变化可影响籽粒淀粉合成及胚乳中蛋白与淀粉粒的嵌合度,并最终造成粒重的增加和淀粉特性的变化。     

灌水对宁春50籽粒干物质积累、产量及水分利用效率的影响

为给春小麦节水高产栽培提供依据,以春小麦品种宁春50为材料,通过田间灌水试验,研究了不同灌水处理（W1：灌二棱水;W2：灌二棱水和拔节水;W3：灌二棱水、拔节水和开花水）对春小麦花后旗叶衰老进程、光合特性、干物质积累与分配、水分利用效率(WUE)及籽粒产量的影响。结果表明,在春小麦花后各阶段,旗叶过氧化物酶（POD）活性随着灌水次数增加而提高,W2处理花后中后期超氧化物歧化酶（SOD）活性最高,增加灌水显著降低旗叶丙二醛（MDA）含量。增加灌水次数明显延缓灌浆后期SPAD值的快速降低,W1处理的叶面积系数（LAI）显著低于W2和W3处理,开花期、灌浆中期旗叶光合特性（Ci、Ts、Gs、Pn）表现为W3＞W2＞W1,灌水次数增加量及其对籽粒产量的贡献率,提高了花后光合产物的积累,促进春小麦灌浆后期千粒重的持续快速增加。增加灌水次数明显提高春小麦籽粒产量、收获指数,但使灌水利用效率、水分利用效率降低。在本试验条件下适度的灌水可实现春小麦节水高产并举。     

水肥一体化条件下施氮量对小麦旗叶叶绿素荧光特性及产量的影响

为探讨水肥一体化条件下施氮量对小麦旗叶叶绿素荧光特性及籽粒产量的影响,以小麦品种济麦22为试验材料,设每公顷施纯氮0（N0）、150（N1）、180（N2）、210（N3）和240 kg（N4）五个处理,通过大田试验分析了不同处理间小麦旗叶PSⅡ 最大光化学量子效率（F_v/F_m）、PSⅡ实际光化学效率（Φ_PSⅡ）、叶绿素相对含量、籽粒灌浆速率及产量的差异。结果表明,花后14~35 d,小麦旗叶F_v/F_m在N3和N4处理间无显著差异,但二处理显著高于其他处理。花后0~35 d,N3处理的旗叶Φ_PSⅡ最高,施氮量再增加至N4时,Φ_PSⅡ无显著变化。花后14~28 d,N3和N4处理的旗叶叶绿素相对含量显著高于其他处理;花后35 d,N3处理显著高于N4处理。粒重和灌浆速率在灌浆前期均随施氮量增加而降低;灌浆后期N3与N4处理间粒重和灌浆速率无显著差异,但二处理显著高于其他处理。籽粒产量在N3处理下最高;在施氮量增加至N4时,籽粒产量不再增加,且氮肥生产效率和氮肥农学效率分别下降了14.6%和24.0%。在本试验条件下,210 kg·hm^-2是兼顾高产和高效的最佳施氮量。     

喷施硒肥对黑小麦籽粒产量及硒含量的影响

为探究叶面喷施硒肥对黑小麦籽粒产量和硒含量的效应,以临黑131和冬黑1206两个黑小麦品种为材料,分别在拔节期（4月17日）、孕穗期（4月28日）和灌浆期（5月14日）3个时期喷施0、10、20、30 mg·L^-14个浓度的亚硒酸钠溶液,分析叶面喷施不同浓度硒对黑小麦籽粒产量及硒含量的影响。结果表明,拔节期和孕穗期喷施硒肥对黑小麦有增产效果,而灌浆期喷施硒肥增产效果不明显;孕穗期和灌浆期喷施硒肥浓度为10 mg·L^-1至20 mg·L^-1时,黑小麦籽粒可达到富硒标准（0.15～0.30 mg·kg^-1）。综上所述,在黑小麦孕穗期叶面喷施浓度介于10 mg·L^-1至20 mg·L^-1之间的Na₂Se0₃溶液,在不减少产量的前提下,可显著提高黑小麦籽粒中的硒含量,使黑小麦籽粒达到富硒水平,增加黑小麦的营养价值。     

高温胁迫下镁对小麦旗叶光合特性及产量的影响

为了解施镁对小麦后期高温胁迫的缓解效应,采用盆栽试验方法,以自然条件为对照(昼夜温度分别为26和16 ℃),研究了灌浆期花后14~20 d 和花后21~27 d高温胁迫（昼夜温度分别为32和22 ℃）下,施镁（20 kg·hm^-2）对小麦产量和旗叶光合特性的影响。结果表明,高温胁迫显著降低了小麦产量,且以花后21~27 d高温胁迫影响最大;施镁能显著增加穗粒数、千粒重和籽粒产量。高温胁迫降低了旗叶叶绿素含量、净光合速率（P_n）、气孔导度（G_s）、蒸腾速率（T_r）、光化学效率（F_v/F_m）和实际光量子产量（Φ_PSⅡ）,各指标均以花后21~27 d高温处理降幅最大,而胞间二氧化碳浓度（C_i）则表现出相反趋势;相同温度处理下,施镁则显著提高了旗叶叶绿素含量、P_n、G_s、T_r、F_v/F_m、Φ_PSⅡ,表明镁素施用能有效缓解花后高温对叶片光合能力的伤害,有助于光合产物的积累和产量的形成。     

密度对不同株型玉米光合特性及产量的影响

对不同密度条件下3个不同株型春玉米的光合特性及产量进行了研究。结果表明,随密度增加叶面积指数(LAI)、初始荧光(F₀)上升,单株功能叶片光合速率(P_n)、PSⅡ的潜在活性(F_v /F₀)、PSⅡ最大光化学量子产量(F_v /F_m)下降;产量构成因素表现为单位面积有效穗数先上升后下降,穗粒数下降,百粒重变化因品种而异。先玉335、金玉4号和吉农大302最高产量分别为9 638.45、8 523.94、8 330.92 kg/hm²;先玉335最适播种密度为75 000株/hm²,吉农大302为60 000～67 500株/hm²,金玉4号为45 000株/hm²。先玉335群体产量与LAI、单株F₀呈正相关,与单株P_n、F_v /F_m、F_v /F₀呈负相关;吉农大302与金玉4号群体产量与LAI、单株F₀呈负相关,与单株P_n、F_v /F_m、F_v /F₀呈正相关,且金玉4号的相关程度要高于吉农大302。     

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).