遮光和渍水对小麦幼苗形态和生长的影响

为了解遮光、渍水及其互作对小麦幼苗形态及生长性状的影响,以长江中下游不同年代小麦品种扬麦1号(20世纪70年代)、扬麦158(20世纪90年代)和扬辐麦4号(21世纪正在应用)为材料,通过盆栽试验研究了遮光、渍水后小麦幼苗主茎叶龄、单株茎蘖数、单株次生根数、苗高、叶面积、干物重、比叶重和根冠比的变化。结果表明,遮光处理显著延缓幼苗叶龄,抑制分蘖的发生,而渍水处理影响不显著;遮光和渍水处理均显著降低单株次生根数、叶面积、比叶重及地上部和根干重,遮光影响程度重于渍水,遮光和渍水同时处理仅对比叶重、地上部和根干重、根冠比表现出一定的累加效应。处理结束后经20d恢复,仅不遮光+渍水处理下叶龄、苗高和比叶重基本恢复到正常生长水平;不遮光+渍水处理下单株次生根数及各处理下根干重表现出恢复趋势。不同品种间幼苗形态和生长性状表现出显著的差异。扬辐麦4号和扬麦158单株次生根数和比叶重均显著高于扬麦1号。不同处理下扬辐麦4号幼苗形态和生长性状相比正常生长幼苗的变化幅度总体上小于其他品种,表现出较好的苗期抗渍及抗弱光能力。     

大田环境下白及苗期地上部与地下部相关性研究

为研究白及幼苗生长的表征指标,以紫花三叉白及幼苗为试材,在7个取样小区初期长势已评Ⅰ、Ⅱ、Ⅲ级基础上,将传统根冠比细分为新根根冠比、块茎根冠比、总根冠比,分析其动态特征,对主要生长性状指标和根冠比指标进行相关性分析。结果表明:大田环境中,初苗期至倒苗期白及幼苗新根根冠比均增大;倒苗期中三类根冠比均以Ⅰ级小区(A_3)最大,块茎和总根冠比以Ⅲ级小区(D_2)最小,新根根冠比以Ⅱ级小区(D_1)最小,主要生长性状指标均以Ⅰ级小区(B)最大,Ⅲ级小区(D_2)最小;相关性分析表明,不同根冠比指标间互呈正相关,根冠比与生长性状指标中仅有新根生物量与新根根冠比存在显著正相关,因此,新根根冠比可更好地表征白及幼苗的生长。     

青蒿素对小麦种子萌发及幼苗生长的影响

为了解青蒿素对小麦种子萌发和幼苗生长的影响,运用室内培养皿法,分析了不同浓度的青蒿素溶液浸种后小麦种子发芽率及幼苗高度、根长、整株鲜重、根和茎鲜重及干重、根系活力等指标的变化。结果表明,青蒿素对小麦种子萌发及幼苗生长有抑制作用,且浓度越高,抑制作用越显著。与无菌水对照相比,青蒿素浸种处理显著降低了小麦的种子发芽率、苗高、根长、根鲜重和茎的鲜、干重,增加了根干重和根冠比。小麦的根系活力和可溶性蛋白含量随青蒿素浓度的增加而递减,可溶性糖含量则随之递增,叶绿素含量则呈先升高后降低的趋势,以20mg·L-1处理含量最高。此外,青蒿素浸种处理对小麦幼苗各项指标的影响与15mg·L-1多效唑相似。     

大豆种子性状、幼苗性状及经济性状间的相关性分析

用22个种子性状差异较大的大豆品种,在测量种子百粒重、百粒容积和容重后,进行田间试验,测定各品种幼苗性状及经济性状的平均值,计算大豆种子性状、幼苗性状及经济性状的相关系数。结果表明:大豆种子粒重和容积与出苗率呈极显著负相关,与幼苗叶绿素含量和基茎粗呈极显著正相关,与幼苗根、茎、叶干物重呈显著或不显著的正相关,与后代百粒重和单株产量呈极显著正相关。幼苗叶绿素含量高的品种,单株分枝数和单株荚数多,百粒重和单株产量高。幼苗茎干重和根干重对单株分枝数和单株产量有显著影响,基茎粗与百粒重呈显著相关。选用大粒品种,既可培育壮苗,又可获得较高的单株产量。     

内生真菌印度梨形孢诱导提高玉米苗期抗旱性研究初探

采用盆栽试验,初步研究内生真菌印度梨形孢诱导提高玉米抗旱性的效应。结果显示,在自然干旱胁迫下,根长、根鲜重、根干重、叶片数、叶面积、叶绿素含量等指标接种印度梨形孢的玉米幼苗比未接种的明显增加,差异达到显著、极显著水平;根干重、叶绿素含量等性状,接种印度梨形孢干旱胁迫处理的幼苗显著地高于未接种干旱处理,表明印度梨形孢真菌具有促进玉米幼苗生长的作用,能有效增强玉米幼苗的抗旱性。     

土壤团聚体大小对大豆出苗和幼苗生长的影响

采用盆栽试验对生长在不同粒径团聚体干旱土壤中大豆出苗和幼苗生长指标进行研究.结果表明,在低土壤含水量条件下,与大粒径团聚体和未筛土壤相比,小粒径团聚体(尤其1～2mm)显著提高大豆出苗率(P＜0.05),缩短出苗时间,显著增加冠干重、苗高及叶面积,显著增加总根长和根表面积,但显著降低主根直径和根干重(P＜0.05).说明大粒径团聚体不利于干旱土壤大豆出苗和幼苗生长,种床内小粒径团聚体可部分地补偿土壤干旱对大豆出苗和幼苗生长造成的危害.     

蚓粪对盐胁迫下小麦幼苗生长及光合特性的影响

为明确添加蚓粪对盐胁迫下小麦幼苗生长及光合特性的影响机理,通过向基质中分别添加10%、20%、40%（苗死亡）比例的蚓粪,同时设不添加蚓粪的单盐胁迫处理和空白对照处理（CK）,分析了添加蚓粪后盐胁迫（150 mmol·L^-1 NaCl）下小麦生长指标（叶长、叶宽、叶面积,地上和地下部干重、根冠比）、气体交换参数及光合色素含量的变化。结果表明,盐胁迫下小麦幼苗各生长指标与CK相比略有下降,但差异不显著。添加蚓粪后,小麦幼苗叶长、叶宽、叶面积、地上部分干重、总干重以及叶绿素a、叶绿素b、叶绿素总含量及类胡萝卜素含量较未添加蚓粪处理均呈明显的上升趋势,而根冠比则呈下降的趋势。添加蚓粪对盐胁迫下小麦叶片气体交换也产生了显著的影响。盐胁迫下,小麦叶片净光合速率显著低于CK,但添加蚓粪后,净光合速率呈明显的上升趋势。这说明基质中添加适量蚓粪可以有效促进小麦幼苗生长和光合作用。     

土壤团聚体大小对大豆出苗和幼苗生长影响研究

采用盆栽试验对生长在不同粒径团聚体干旱土壤中大豆出苗和幼苗生长指标进行研究。结果表明,在低土壤含水量条件下,与大粒径团聚体和未筛土壤相比,小粒径团聚体（尤其1～2 mm）显著提高大豆出苗率（P＜0.05）,缩短出苗时间,显著增加冠干重、苗高及叶面积,显著增加总根长和根表面积,但显著降低主根直径和根干重（P＜0.05）。说明大粒径团聚体不利于干旱土壤大豆出苗和幼苗生长,种床内小粒径团聚体可部分地补偿土壤干旱对大豆出苗和幼苗生长造成的危害。     

亚麻根系生长动态规律的研究

选用不同基因型的亚麻材料,对其根系体积和干重的动态增长规律进行了研究,结果表明：亚麻根系体积和干重的增长符合Logistic生长方程,根体积的渐增期为28.7～37.4d,快增期为32.1～36.7d,缓增期为27.8～40.3d,根体积增长与快增期、缓增期增长速率呈显著正相关,与平均增长速率、渐增期增长速率、快增期增长速率呈极显著正相关,与增长期呈正相关但不显著。干重的渐增期为33.5～40.00d,快增期为4.09～8.19d,缓增期为23.4～38.50d。根干重增长量与平均增长速率,最大增长速率,渐增期长短,渐增期增长速率,快增期增长速率,缓增期增长速率等性状呈极显著正相关。     

早熟大豆发芽期和苗期耐寒性鉴定

对9个大豆品种的发芽和苗期的耐寒性进行了鉴定,在常温(25℃)和低温(10℃)胁迫下分别测定了种子发芽特性及幼苗素质的各项指标.以各性状低温与常温下测定值的比值(相对值)作为耐寒性评价指标..结果表明,在低温逆境下,苗比根对低温更敏感,耐寒品种的根和幼苗总干重未下降.通过聚类分析,解决了由于性状相对值差异微小而难以评价大豆耐寒性的问题,将品种分成了耐寒、中等耐寒和低温敏感3类.相关性分析表明,相对发芽率、相对幼苗全长、相对地上部苗高、相对地上部苗干重及相对根干重之间显著正相关,是较好的耐寒性评价指标.     

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).