亚种间杂交稻籽粒充实动态及生理研究

木文比较了常规稻特青、品种间杂交稻Ｗ６１５４Ｓ／特青和亚种间杂交稻Ｗ６１５４Ｓ／培矮６４、特青／ＤＴ的强弱势粒充实情况，以及充实过程中呼吸速率、ＡＴＰ含量、磷酸化酶活性动态，以探讨亚种间杂交稻籽粒充实低的原因。结果表明：亚种间杂交稻弱势粒在开花初期存在着较长时间的“滞缓期”，其呼吸速率、ＡＴＰ含量及磷酸化酶活性等生理活性维持在一个极低的水平，从而表现出灌浆启动慢，灌浆高峰推迟，最终导致空秕粒多，充实度低。     

亚种间杂交水稻灌浆特性的调节及其对产量的影响

 以亚种间组合汕优413和协优413、籼型杂交组合汕优10号为材料进行研究。结果表明对弱势粒灌浆的影响,IAA具有代替强势粒的作用。即使剪去顶端3个一次枝梗、营养物供应非常充足,由于IAA的存在,弱势粒的灌浆也较为迟缓,最终形成大量空秕粒,与不修剪的对照接近,说明弱势粒的灌浆主要受IAA调控,也证明强势粒以“顶端优势”的方式抑制弱势粒的灌浆。     

内源IAA对杂交稻强、弱势粒灌浆增重的影响

以超级杂交稻协优9308和杂交稻协优9312、Ⅱ优162及其相应恢复系为材料,对灌浆初期籽粒中内源IAA、糖分的变化,以及IAA抑制剂对IAA以及3H 标记葡萄糖吸收分配和籽粒灌浆的影响进行了研究。结果表明在籽粒灌浆初期强势粒的IAA含量以及增重的速度始终高于弱势粒。在开花受精7 d以前,强势粒中果糖、葡萄糖及蔗糖的含量高于弱势粒,之后相反。强、弱势粒间存在的这种灌浆势差异,杂交组合大于其相应的恢复系。IAA合成及运输抑制剂明显降低3H 葡萄糖在籽粒中的分配。外源IAA对幼穗的处理,缩小了强、弱势粒间结实率的差异,使整穗的结实率也有所提高。     

IAA与亚种间杂交稻籽粒发育的关系及烯效唑的调节

 以汕优413及其父本品种中413为材料,研究了内外源IAA在籽粒发育过程中的作用及植物生长延缓剂S-07对其强、弱势粒灌浆过程的影响。在灌浆前期,强势粒抑制弱势粒的发育,外源IAA可代替强势粒的这种抑制作用;灌浆过程中强、弱势粒内源IAA的变化动态存在差异,其中强势粒的内源IAA在开花后急剧上升,8 d左右达最高峰;而弱势粒的IAA水平开花后则有一段约12 d的“滞缓期”,在开花后20 d左右才有一高峰出现。强弱势粒对3H-IAA的合成和吸收能力差异可能是导致其内源IAA水平不平衡的原因之一。孕穗末期喷施S-07可部分抑制强势粒的发育而相对促进弱势粒的发育,提高弱势粒千粒重;孕穗末期喷施S-07溶液可降低强势粒但提高弱势粒灌浆前期的内源IAA水平。     

植物激素对杂交稻籽粒灌浆及蔗糖合酶活性的影响

 以亚种间杂交稻两优培九和品种间杂交稻汕优63为材料,对籽粒灌浆期间的内源激素含量和酶活性进行了测定分析,并结合外源激素对水稻籽粒灌浆过程的调控试验,分析了脱落酸对蔗糖代谢关键酶——蔗糖合酶活性的调节作用。结果表明,灌浆前期强势粒中生长素、玉米素核苷和脱落酸（ABA）含量明显高于弱势粒,并与籽粒最大灌浆速率、平均灌浆速率、籽粒充实率和粒重均呈显著或极显著正相关。强势粒中蔗糖合酶活性明显高于弱势粒,且达到峰值的时间也早于弱势粒。籽粒灌浆速率、籽粒充实率、粒重和淀粉积累速率与蔗糖合酶活性呈显著正相关。花后8 d对稻株喷施低浓度ABA显著提高了籽粒中ABA含量和蔗糖合酶活性,增加了粒重和籽粒充实率。喷施ABA合成抑制剂氟草酮作用则相反。上述结果说明,植物激素尤其是ABA对水稻籽粒灌浆有重要的促进作用,其作用在很大程度上是通过调节籽粒蔗糖合酶活性实现的。     

超级稻花后强、弱势粒淀粉合成相关酶活性和激素含量变化及其与籽粒灌浆的关系

 种植4个超级稻品种\[两优培九和Ⅱ优084（杂交籼稻）、淮稻9号和武粳15（粳稻）\]和2个高产对照品种\[汕优63（杂交籼稻）和扬辐粳8号（粳稻）\],观察其结实期强、弱势粒中蔗糖合酶（SuSase）、腺苷二磷酸葡萄糖焦磷酸化酶（AGPase）、淀粉合酶（StSase）和淀粉分支酶（SBE）活性及玉米素+玉米素核苷（Z+ZR）、3 吲哚乙酸（IAA）和脱落酸（ABA）含量的变化,并测定了强、弱势粒灌浆速率。结果表明,超级稻品种强势粒的最大灌浆速率、到达最大灌浆速率的时间、平均灌浆速率和糙米重与对照品种差异较小,超级稻品种弱势粒的灌浆速率和糙米重显著低于对照。灌浆期强、弱势粒的SuSase、AGPase 、StSase 和SBE活性变化及Z+ZR、IAA 和ABA 含量变化均呈单峰曲线。弱势粒的SuSase、AGPase、StSase 和SBE的峰值活性和平均活性及其Z+ZR 和IAA的峰值含量和平均含量均低于强势粒。弱势粒的ABA 峰值含量和平均含量显著高于强势粒,超级稻品种高于对照品种。籽粒灌浆速率与SuSase、AGPase和StSase 活性及Z+ZR 和IAA含量均呈显著或极显著正相关,与SBE活性及ABA含量的相关不显著。说明超级稻品种弱势粒中较低的SuSase、AGPase和StSase活性及较低的Z+ZR和IAA含量是其灌浆速率小、粒重轻的一个重要原因。     

品种间两系杂交稻与三系杂交稻对比试验

我国品种问两系杂交稻的研究成果开始转为生产力。湖北省光敏核不育系已配制品种间杂交组合在生产上试种、示范,湖北农科院配制的N5047S×R9-1、N5088S×R9-1等粳型两系法杂交稻组合,试种和示范已在万亩以上;广西农科院培育的籼型两系杂交稻KS-7×03、KS×03和KS14×03也示范千亩以上,比三系杂交稻增产10-13％;福建农学院培育的两系杂交稻“光优6063”,亩产631.1公斤,比目前大面积推广的三系早杂交稻威优64,增产18％以上;湖南、湖北等省配制的W6154S×特青,小面积试种,表现比汕优63增产5％左右。     

灌浆期低温对离体玉米子粒灌浆过程及内源激素的影响

以郑单958为材料,采用子粒离体培养方法,研究灌浆期低温对玉米强、弱势粒灌浆特性及内源激素的影响。研究表明,灌浆期低温分别减缓强、弱势粒平均灌浆速率15%、23%,延长灌浆时间约8 d,最终粒重分别降低3%、9%。低温处理下,GA_3、IAA、ZR含量与灌浆速率显著相关;受低温影响,强、弱势粒的激素含量变化趋势相近,与常温相比,子粒GA_3含量先增加后减少,IAA、ZR含量低于对照,且对弱势粒的影响大于强势粒。低温对内源激素含量的影响是导致灌浆速率降低的主要原因之一。     

烯效唑对杂交水稻籽粒灌浆及产量的影响研究

以杂交稻组合汕优63为材料,探讨了不同施药时期(浸种、孕穗期喷施)和不同质量浓度(0,10,20,40,80 mg/L)烯效唑处理对籽粒生长过程及产量的影响.结果表明,烯效唑对强势粒生长有一定抑制作用,但同时却促进了弱势粒的生长,在一定程度上具有协调强、弱势粒灌浆的作用,降低成熟期强势粒单粒重而提高弱势粒单粒重;使强势粒的终极生长量降低,达最大生长速率的时间延后,从而延长弱势粒的灌浆时间,提高弱势粒的灌浆速率及最大干重;由于烯效唑对弱势粒生长的促进作用,显著提高了其穗实粒数,进而提高了单穗籽粒干重及水稻产量.处理时期不同,其最佳浓度不同;浸种处理以质量浓度为40mg/L时产量最高,喷施处理以20mg/L时的产量最高.     

氮肥用量对小麦籽粒粒重及淀粉含量的影响

为明确氮肥对小麦强、弱势粒粒重及淀粉品质的影响与调控,以强筋小麦烟农21和中筋小麦鲁麦21为材料,研究了三个氮肥水平(120、240、360 kg N/ha,分别用N1、N2、N3表示)下小麦籽粒增重过程及直、支链淀粉含量的变化规律。结果表明,随氮肥施用量的增加,强、弱势粒千粒重均降低,且灌浆后期处理间差异显著。两个品种强势粒千粒重均高于弱势粒;随氮肥施用量的增加,烟农21强、弱势粒灌浆速率均降低。两个品种强势粒灌浆速率均高于弱势粒;随氮肥使用量的增加,两品种强、弱势粒直链淀粉含量降低。支链淀粉从花后7 d开始积累,花后35 d含量达到最大值。当氮肥施用量为240 kg N/ha时,鲁麦21强、弱势粒支链淀粉含量较高,分别为48.73%和45.03%;烟农21对氮肥的反应与鲁麦21基本一致,强、弱势粒支链淀粉含量分别为57.04%和55.94%。     

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.