甘兰型油菜受精过程的细胞学观察

本工作对甘兰型油菜(Brassica napus L.)受精过程作了较详细的观察,结果如下: 1.甘兰型油菜的受精过程进行得比较缓慢,大约从开花后24小时受精开始,48小时左右一部分卵细胞完成受精过程。60小时前后大部分胚珠的卵细胞完成受精过程形成受精卵。受精卵在开花后10天左右进行第一次细胞分裂。 2.胚珠一般为珠孔受精,从受精开始到受精卵形成突起,一直都有花粉管进入胚珠,不断把内含物注入胚囊,并从一侧环抱卵细胞,它们很可能参与受精卵的发育。 3.卵细胞受精,精核一般从卵核核仁的对方进入卵核。入卵核后的精核核仁由小长大,到两性核仁等大时融合形成受精卵。受精卵很快形成突起,突起伸长为管子,细胞核慢慢移到管端,这时细胞进行第一次分裂。 4.极核一般比卵受精早,受精前极核靠近卵器,当精核进入极核细胞质时,两极核即向胚囊中央转移,在转移过程中,完成受精作用。 5.在胚珠发育过程中,发现有停留在不同时期的败育胚囊和中途解体的卵细胞和极核。     

橡胶树成熟胚囊超微结构研究

橡胶树（Ｈｅｖｅａ ｂｒａｓｉｌｉｅｎｓｉｓ Ｍｕｅｌ－Ａｒｇ．）成熟胚囊的超微结构电镜观察结果表明：（１）卵细胞具明显的极性，细胞核和细胞质的大部分颁在最近合点端，珠孔端的２／３为大型液泡所占据。细胞壁不完全，其合点端没有细胞壁，助细胞和中央细胞在这一区域也没有细胞壁；因此，卵细胞与中央细胞，卵细胞与助细胞，或助细胞与中央细胞之间，只有质膜作为分界。细胞器的大部分分布在细胞核周围细胞质中，其中质     

纳豆的保健功效及开发应用

利用石蜡切片和压片等方法观察热研2号柱花草传粉受精过程花朵形态变化及双受精作用过程。凌晨6时绝大多数花蕾已进行自花授粉，花粉粒在柱头上经过2～3 h后萌发。授粉后2～3 h，花粉管沿子房内壁生长进入胚珠，进行珠孔受精。开花后5～6 h，精卵细胞融合，几乎同一时间精子与极核融合。     

福两优63制种与繁殖技术

福两优６３是两系杂交早稻,由温敏型核不育系ＦＪＳ－１和恢复系明恢６３配组而成。利用光（温）敏核不育系和恢复系作父本,辅助授粉生产杂种一代的过程,叫两系制种。两系制种和三系制种母本（不育系）都是靠异交结实,制种原理基本一样,所以两系制种完全可以借助三系制种的技术和成功的经验。两系制种和三系制种最大差别是不育系,两系制种核不育系的育性受一定温、光条件所控制,目前所用的光（温）敏核不育系,一般在大于１３－５ｈ的长日照和日均温高于２４℃的条件下,表现为雄性不育,可以制种;当日照短于１３－５ｈ和日平均温度…     

利用离体培养克服花生杂交不亲和性的研究

利用离体培养克服花生杂交不亲和性的研究／曲咏梅（莱阳农学院农学系），唐荣华…莱阳农学院学报．—１９９４，１１（１）．－１～５将花生梧油１号和Ａ．ｓｐ（９６１８）杂交授粉后的胚和胚珠在不同种类和浓度激素的ＭＳ培养基上进行离体培养。从离体胚的胚培养上获得...     

利用橡胶树橡胶转移酶活性早期预测橡胶树产胶能力的研究

对热研７－３３－９７、ＲＩＭ６００，ＰＢ８６，海垦１号，天任３１４５等５个品系一年生幼苗的橡胶转移酶活性于不同月份进行测定，其结果基本一致，与橡胶产量呈正相关，对热研４３－（８－７９）、ＲＲＩＭ７１２，合口３－１１，南强１－９７等１３个品系的橡胶树幼苗的橡胶转移酶活性的测定结果表明，橡胶转移酶可以作为橡胶树产胶能力的重要指标，对橡胶树产量进行早期预测。为了适应早期预测工作，建立了简便快速的全胶乳橡     

大豆去雄授粉时间与杂交成活率关系的研究

本文在田间试验的基础上对夏大豆６种不同去雄授粉时间的杂交成活率进行统计分析，各方法及杂交成活率依次为：（１）下午去雄授粉６２．５％，（２）下午去雄授粉次晨再授粉５５．８％，（３）下午去雄次晨授粉４８．３％，（４）下午去雄次日下午授粉４５．８％，（５）下午去雄第三日晨授粉３２．５％，（６）晨去雄授粉２１．７％。方法间差异达显著水平。     

水稻无融合生殖材料PDER选育的初步研究

通过离子注入Ｆ１代杂交种子，从后代中选育出２个早发生胚水稻品系，开花前１～２ｄ，未经授粉受精，卵细胞能自行分裂成多细胞原胚，发生频率高达２６．８％，用显性紫色稻作父本测交，Ｆ１代出现一定比例母本类型植株。经细胞胚胎学观察，已证实该材料存在二倍体孢子生殖（Ｄｉｐｌｏｓｐｏｒｙ）和无孢子生殖（Ａｐｏｓｐｏｒｙ），同时还存在未受精极核分裂成初生胚乳核的现象。     

高分子量麦谷蛋白亚基的编号,基因,带谱及品质权重

（１）１－１２号高分子量麦谷蛋白亚基的分子量依次递减，２号亚基在５％胶中易分辨，１３－１６号亚基介于７号和８号亚基之间；（２）１号、２号、Ｎ和２５号亚基由１ＡＬ上的Ｇｌｕ－Ａ１位点上的４个等位基因所控制；     

茶树受精作用的研究

本文研究了茶树卵器的结构和受精过程。茶树的卵器由1个卵细胞和2个助细胞组成。有些卵器的助细胞之一在花粉管进入胚囊之前已开始退化,有些卵器的2个助细胞直到受精时仍保持正常的结构。花粉在柱头上萌发后,花粉管通过花柱通道到达珠孔,然后穿过退化的助细胞或助细胞与胚囊壁之间进入胚囊,并释放出2个精子和其它内含物。两个精子分别接近并贴附在卵核和两极核上,两性核的核膜溶解,精核染色质沉入雌核,并随之松解。最终雄性核仁和雌性核仁合并,形成具有单核的合子和初生胚乳核。初生胚乳核随即进行核分裂。通过鉴定两性核仁结合与否和观察     

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.