诱导橡胶多倍体与其细胞学研究续报Ⅰ

本文报道从海垦8,热研2—14—39,热研7—18—65等优良无性系芽条诱导出45株多倍体植株,经细胞学鉴定,这些植株的体细胞染色体数大多为2n=54～72,每个植株的多倍细胞均占其总分裂细胞数的60％以上。这些多倍体植株的外部形态发生了显著的变异,如叶片显著增厚、叶色浓绿、叶脉增粗等。目前这些植株已进入无性系第2代和第3代筛选,其中最大的多倍体植株已高达2米,而且已开始出现多倍分枝。在试验研究过程中,我们发现采用秋水仙碱和激动素等诱导剂时,诱导当代芽条的第一蓬叶大多数属于嵌合体。至第二蓬叶时则几乎全部恢复正常(2n=36)。将当代第一蓬叶的嵌合体茎干进入无性第一代分离筛选时,约产生千分之一的突变芽,只有将这些突变芽继续芽接至第二代筛选时才能获得较多的多倍体植株,但这一代仍然有分离现象。分离出正常的植株约占30％。从无性第二代中再经细胞学鉴定,选出较纯的多倍体植株进行无性第三代筛选时,所获得的第三代植株几乎全部属于多倍体植株。     

诱导橡胶多倍体及其细胞学研究续报Ⅱ

一、已经用化学和物理方法诱导出多倍体无性系及无性系材料共12个,经过3～7代分离筛选,获得稳定的多倍体植株共1000多株,最大的已高达4米以上。二、从诱导多倍体研究中,提出了从诱变处理,分离筛选,到细胞学鉴定和形态、组织学鉴定等一套行之有效的方法。目前在一般情况下,已有把握对所需要诱导的优良品系在1.5～2年内诱导成稳定的多倍体无性系。三、对诱导出的多倍体无性系进行了叶脉胶预测产量鉴定,其中许多无性系有比对照(二倍体)高产的趋势。     

苎麻多倍体诱导中的嵌合现象及累积诱导效应

苎麻子叶苗茎尖秋水仙素处理的直接效应是产生倍性嵌合生长锥,继而由其分别发育成地上茎和地下茎。处理当季只有少部分植株表现出多倍体特征,但嵌合体地下茎在多季宿根年代中可间歇或连续地发出不同倍性分株,据两年观察鉴定,其累积平均多倍体诱导率已高达49.4％。不同秋水仙素浓度和不同处理时间的多倍体累积诱导率差异显著。用综合诱导率进行评价更能反映各处理的实际效果,以低浓度较长时间处理(0.1％,3天)的综合诱导效果最佳(59.7％)。关于苎麻多倍体诱导中嵌合体形成及其特点以前未见报道。     

橡胶树人工多倍体的形态性状与产胶特征

以经秋水仙素诱导成功的海垦2、PR107和RRIM6003个品系多倍体(处理)为材料,以它们的亲本二倍体为对照,研究16a树龄橡胶树人工多倍体无性系的形态特征和干胶含量。结果表明:3个橡胶品系具有多倍体的形态特征,又表现出嵌合性。它们的树围、生势不及相应的二倍体,干胶含量也不优于二倍体。大多数多倍体植株的树干表面呈现不同程度的隆凸或凹陷。叶片的叶形指数、一级侧脉数、主脉导管列数、栅栏组织厚度、海绵组织厚度和叶片厚度6个主要性状在多倍体与二倍体之间均存在显著或极显著差异,体现了多倍体与二倍体之间的差异性;但在多倍体的植株间或部位间以及二倍体的植株间或部位间,表现出来的差异性错综复杂,无一定的规律性。多倍体树皮结构与二倍体的差异也很明显,如多倍体射线较二倍体的少,射线细胞较宽,树皮弦切面上的“网眼”(多列射线排列成的梭状结构)较宽、形状不规则、排列较混乱等。      

澳洲坚果多倍体的化学诱导及流式细胞术鉴定

以澳洲坚果品种‘云澳57’、‘云澳51’、‘云澳41’和‘云澳58’的萌动种子和幼嫩顶芽为材料,采用浓度为0.1％~0.3％的秋水仙素分别处理48、72（种子）或96 h（顶芽）,对种子的发芽率、幼苗形态和顶芽存活率等进行观测,并对有形态性状变异的植株进行流式细胞术倍性检测。结果表明：随着秋水仙素浓度和浸泡时间的增加,种子的发芽速率减慢,发芽率呈现显著的降低趋势,且不同品种对秋水仙素浓度的敏感性有所差异;大多数处理后种子萌发的幼苗出现了植株矮化、生长缓慢、第一对真叶显著变小或畸形甚至缺失、茎干明显增粗、叶尖出现分叉或卷曲、根系变为须根系等性状,部分幼苗叶片显著增大或分枝显著增多。不同浓度的秋水仙素溶液均可导致澳洲坚果嫁接苗顶芽存活率的降低,但大多顶芽并未出现形态变化。流式细胞术检测发现,在处理后种子萌发的幼苗中出现了多倍体,但均为2C+4C或2C+4C+8C的嵌合体,且多倍体诱变率在5％以下;经秋水仙素处理的嫁接苗顶芽并未检测到倍性变化。     

橡胶树花芽不同发育阶段秋水仙素诱导花序变异效果的研究

橡胶树混合芽（即橡胶树“花芽”）发育不同联合会的形态结构观察及秋水仙素对其染色体数诱导加倍的研究结果表明：长１．５～３．９ｍｍ的萌动混合芽处于圆锥花序的分化初期，其生长锥下方刚形成花序的一级分枝原基，细胞分裂量较大，在该阶段用０．２５％秋水向素溶液进行染色体数加倍处理，较易获得整体加倍的变异花序。     

苎麻三倍体及非整倍体研究初报

本研究探讨了苎麻多倍体的各种诱导方法,以组织培养方法最为理想,诱变频率可高达56.10％。采用组织培养不定芽技术获得了四倍体细胞达94％的单株和三倍体细胞达86％的单株,并发现了非整倍体细胞。将稳定的四倍体与二倍体杂交,得到了大量三倍体苎麻,以及各种类型的苎麻非整倍体材料。还初步研究了这些材料的形态特点,选出了一些营养生长优势极强的株系。     

亚麻多倍体诱导技术研究——I．秋水仙碱诱导形态变异率的影响因子研究

为建立亚麻多倍体化学诱导技术体系，通过清水浸泡时间与秋水仙碱溶液浓度、处理温度、处理时间的比较试验，研究了外界因子对亚麻多倍体诱导形态变异率的影响。结果表明：亚麻多倍体诱导，以清水浸种16小时，转入0．16％的秋水仙碱溶液，在20℃条件下浸泡12小时为最佳，其成活率为36．07％，诱导率达到24．67％，则诱导成活率为8．9％。     

苎麻多倍体诱导技术研究

以秋水仙素为诱变剂,此较了不同浓度和时间对苎麻不同器官或部位进行处理的诱导效果。种子处理,由于胚根生长受到严重抑制,生活力差,成活率低,有效诱导率仅0.65％。首次成功地进行了苎麻实生幼苗茎尖处理,平均诱导率达9.04％,为国内已报道最高诱导率的5倍。处理的直接效应多数形成嵌合体,采用嫩梢扦插等繁殖方法即可分离完全多倍体。根据苎麻多倍体主要特征特性,采取大田目测或结合成熟花粉粒镜检进行初选,最后以染色体计数为准的鉴定程序,既省时又可靠。     

低浓度秋水仙素离体诱导甜叶菊多倍体技术体系的建立

以甜叶菊茎段为外植体,采用不同低浓度秋水仙素在甜叶菊试管苗茎段再生苗初期进行长时间持续处理,以探讨低浓度秋水仙素诱导甜叶菊多倍体的优势及适合长时间诱导甜叶菊的秋水仙素浓度,简化甜叶菊离体诱导多倍体技术环节。结果表明:0.025%的秋水仙素浓度适合于甜叶菊多倍体离体诱导的持续诱变,直至试管苗再生而无需清洗外植体和更换培养基,简化了诱导技术环节,提高了甜叶菊多倍体离体诱导效率;多倍体植株田间农艺性状表现为叶片大而厚实、开花延迟、花蕾较大等特征。旨在建立低浓度秋水仙素离体诱导甜叶菊多倍体技术体系。     

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).