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1.
我国双季稻生产机械化制约因子与发展对策 总被引：29，自引：0，他引：29
20世纪70年代中期以来,我国双季稻种植面积占水稻总面积比例持续下降,从当时的71%下降到近年的40%左右。按单位土地面积计算,双季稻早晚两季产量比单季稻高57%左右,改单季稻为双季稻种植,在保持稻田面积不变情况下,可大幅提高种植面积和总产。双季稻种植面积下降的主要原因是机械化程度较低,生产效益不高。制约双季稻全程机械化的关键是机插秧比例不高,特别是双季稻机插秧季节紧张,适宜机插搭配品种少,机插质量较差,及主要作业环节机械化不配套等。发展双季稻生产全程机械化的关键途径是:选育和筛选一批适宜双季稻机械化生产的品种,优化双季稻机械化生产的品种搭配布局;创新一批双季稻机械化生产模式,完善关键环节技术模式;创制一批双季稻机械化生产的机械装备,实现机具装备配套;研发一批双季稻全程机械化栽培技术,推进农机农艺技术配套与应用。 相似文献
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早、晚季水稻采用塑料盘旱育秧抛植配套栽培技术，可以达到高产高效的目的，同时减轻了劳动强度。文中介绍了早晚两季盘育旱秧的方法和抛秧技术及大田栽培管理措施。该技术是双季稻高产高效栽培的新途径。 相似文献
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2004年选用广东省水稻研究所提供的华南双季稻品种，通过比较广州早稻栽培与湘西北张家界中稻试种的产量与米质变化，以探索华南双季优质稻与广适性超级稻对不同气候生态条件的适应性。结果表明，各品种在两地生育期表现相近；张家界水稻生育前期和中期气温较高，因而有效穗数比广州增加，但每穗总粒数显著减少；由于张家界8月上旬水稻抽穗开花期常出现过高温时段，因而结实率下降，但水稻灌浆结实期气温比广州低，故千粒重比广州高；两地各品种产量水平相当，大多在7．50～8．25t／hm^2；在稻米品质方面，张家界稻区的糙米率和精米率下降而垩白粒率和垩白度增加，稻米直链淀粉含量大多高于广州。张家界低海拔地区引进华南双季稻品种作中熟中稻栽培。表现出良好的气候生态适应性。 相似文献
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华南籼稻稻米品质性状早晚季间变化规律探讨 总被引：1，自引：0，他引：1
目前 ,华南双季稻作区种植的常规稻品种大多数都是早晚兼用型品种 ,不少生产上应用的杂交组合也属早晚兼用型。早晚兼用型品种 (组合 )在早晚季种植时稻米品质会有所不同 ,普遍的经验认为晚季稻米的食味品质优于早季 ,但对于稻米蒸煮、外观、碾米、食味等具体品质指标在早晚季的变化尚缺乏深入的量化研究。本文采用国家优质稻谷标准ＧＢ／Ｔ１７８９１-１９９９,测定并分析了９个华南籼稻品种 (组合 )在６个试点早晚两季种植的稻谷样品的品质指标 ,试图揭示华南籼稻品种 (组合 )早晚季品质变化的规律 ,讨论了新国标的可操作性。一、材料与方… 相似文献
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为了解2022年罕见持续高温天气下湖南省一季稻及再生稻灌浆结实情况,对湖南省一季稻种植区域内常规稻和杂交稻结实率和籽粒充实度进行调研。结果表明,高温显著地降低了一季稻结实率,且对常规稻的影响大于杂交稻。同时,高温对一季稻结实率的影响存在明显的地域性差异,湖南省北部区域的结实率受高温影响较大,28°N以北区域的常规稻和杂交稻结实率分别比28°N以南区域降低了6.7和3.1个百分点。此外,高温对再生稻头季和再生季籽粒灌浆结实和产量的影响存在明显差异,头季和再生季分别于7月15日之前和9月1—17日齐穗的再生稻品种,能一定程度上缓解高温对再生稻两季结实率和产量的影响。针对高温对湖南省一季稻和再生稻结实的影响以及再生稻生产现状,提出了应对全球变暖环境下高温胁迫对一季稻结实影响的策略：选育耐高温水稻品种;在经济效益相当的条件下,湖南省28°N以北地区选种杂交稻;由一季稻种植模式转变成再生稻种植模式,并搭配适宜播期。 相似文献
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灌浆结实期不同时段温度对水稻结实与稻米品质的影响 总被引：31，自引：4，他引：31
利用人工气候箱在水稻灌浆结实期不同时段进行温度试验,研究温度对水稻结实与稻米品质的影响。结果表明,灌浆结实期40℃高温处理后籽粒结实率显著降低,粒重下降,外观品质和食味品质变差。不同水稻品种对灌浆结实期温度的响应表现不一致。在试验条件下,华粳1号开花受精的敏感温度为35℃,而特优559开花、灌浆结实的最适温度为30℃,该温度处理结实率、粒重较高,外观品质以及食味品质较优。此外,灌浆结实期不同时段的高温对水稻结实与稻米品质的影响也存在显著差异：结实率对高温最敏感的时期是开花后1~5 d,粒重对高温最敏感的时期是开花后11~20 d;而温度对稻米品质影响最大的时期主要在花后16~20 d,25 d后温度处理影响较小。因此,灌浆前期适宜的温度条件对水稻优质栽培意义重大。 相似文献
7.
播期和种植密度对玉米子粒灌浆的影响 总被引：7，自引：1，他引：6
通过设计不同的播种时期和种植密度,研究不同处理造成的温光生态条件和群体结构差异对玉米不同部位子粒灌浆的影响。结果表明,播期和种植密度对玉米中部子粒灌浆速率影响主要表现在灌浆后期,密度影响较大;播期和种植密度对玉米顶部子粒灌浆速率主要是阶段性影响。播期对玉米中部子粒含水率影响较大,种植密度对玉米中部子粒含水率没有影响。 相似文献
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长江中下游稻区双季晚粳稻产量生理与资源利用效率研究进展 总被引：2，自引：0，他引：2
长江中下游稻区是我国水稻主产区,同时又是单、双季稻混作区。目前,随着经济发展和人民生活水平的提高,人们对优质大米,尤其是优质粳米的需求日益增加,因此,在双季稻生产中引入粳稻具有重要的现实意义。本文介绍了长江中下游双季稻的温光资源特性,总结了现有双季晚(籼/粳)稻品种的种植表现,从产量、产量结构、干物质积累、群体动态、生育期、温光利用率、稻米品质等方面比较了长江中下游稻区晚粳与晚籼的可能差异。总体来说,双季晚粳在产量、每穗粒数、结实率、千粒重等方面均显著高于晚籼;前期干物质积累两者无显著差异,但是后期干物质积累量晚粳要高于晚籼,晚粳的灌浆率显著高于晚籼,这预示着双季晚粳具有更高的产量潜力。粳稻比籼稻有着较平稳的茎蘖动态,这使其具有更强的后期光合能力、更高的后期光能利用率;全生育期晚粳比晚籼长,主要体现在推迟抽穗结实,延长结实灌浆期;粳稻全生育期积温和光照时数均显著高于籼稻,粳稻后期叶面积指数大于籼稻,光合势亦高于籼稻,而在生育前期(拔节至抽穗期)两者对温光资源的利用基本相当,因此温光利用率晚粳显著高于晚籼;另外,晚粳的稻米品质要优于晚籼。因此,相对于双季晚籼,双季晚粳具有更高的应用推广价值。 相似文献
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Lakshman Lal 《Potato Research》1987,30(2):329-334
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. 相似文献
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《Journal of Crop Improvement》2013,27(2):81-114
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. 相似文献
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Joseph E. Laferriere Charles W. Weber Edwin A. Kohlhepp 《Plant foods for human nutrition (Dordrecht, Netherlands)》1991,41(3):277-282
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. 相似文献
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M. I. Siri P. Villanueva M. J. Pianzzola L. Franco Fraguas G. Galván M. Acosta F. Ferreira 《Potato Research》2004,47(3-4):127-138
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. 相似文献
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Novel food and non-food uses for sorghum and millets 总被引：4，自引：3，他引：4
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. 相似文献
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Alejandro Carlos Tozzini María Fernanda Ceriani María Verónica Saladrigas H. Esteban Hopp 《Potato Research》1991,34(3):317-324
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 RXact). 相似文献
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Rita Favas Janaína Morone Rosrio Martins Vitor Vasconcelos Graciliana Lopes 《Marine drugs》2022,20(3)
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. 相似文献
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Alejandro M. S. Mayer Abimael D. Rodríguez Orazio Taglialatela-Scafati Nobuhiro Fusetani 《Marine drugs》2013,11(7):2510-2573
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. 相似文献