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利用海口市1961～2010年日照时数实测资料,分析年代际、年际和季节的气候变化特征,同时与总云量、低云量、相对湿度和降雨量资料,进行相关分析。结果表明：近50年海口市日照时数呈下降趋势,每10年偏少117.2 h,其中2001～2010比1961～1970 下降了20%以上。海口市日照减少与低云量的增加有密切关系,与夏秋季节的降雨量也有关系。 相似文献
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完善生态建设 构建和谐园林 总被引：4，自引：0，他引：4
随着"生态园林"理念的不断深入,人们对园林绿化的概念、内涵也提出了更高的要求,体现在各植物元素的和谐统一。园林物种的多样性是维系城市绿地系统稳定的基础,通过合理筹划和高效利用绿化资源,实现绿化生态效益的最大化。要根据绿地周围的城市景观元素,更多地把绿地景观融入到整个城市环境中,使人工景观与自然景观更加自然地交融在一起,优化植物配置,弘扬城市园林个性,做到人与自然和谐共处,用可持续发展观建设生态人居城市,构建和谐园林。我们要进行防灾减灾规划研究,加强防灾绿地建设,提升城市生态环境质量。 相似文献
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为了解浙江省桐庐县稻田耕层土壤肥力现状及其演变趋势,利用历史资料和近期地力评价调查数据,探讨了近30年来桐庐县稻田耕层土壤主要肥力指标的变化特征。结果表明,近30年来,桐庐县稻田耕层土壤主要肥力指标发生了较大变化,但变化方向和变化程度因养分种类和区块而异。土壤p H值有轻微的酸化趋势,平均降低0.07个p H值单位;土壤阳离子交换量总体上以中低水平为主;土壤有机质显著降低,平均降幅为17.32%,以分水区块下降最为明显,降幅为24.17%;土壤有效磷和速效钾显著提升,平均增幅分别为173.75%和63.05%。其中,土壤有效磷已出现了累积现象,以桐君区块累积最为明显,增幅高达316.24%;土壤速效钾虽提升显著,但仍处于中等水平,桐君区块提升最多,增幅为112.62%。分析认为,施肥结构和种植制度的改变是引起桐庐县稻田土壤肥力变化的主要原因。 相似文献
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套作弱光胁迫对大豆苗期根系形态和生理活性的影响 总被引：5，自引：0，他引：5
研究玉米-大豆带状套作弱光环境下大豆苗期根系形态特征、生理特性和生物量积累,明晰苗期大豆根系对套作荫蔽的响应规律,筛选适宜玉米-大豆带状套作的大豆品种,为改良大豆对荫蔽胁迫的适应能力提供理论依据。以NTS1007、桂夏3号和南豆12等3个根系特征不同的大豆品种(系)为试验材料,在盆栽试验条件下,采用挖掘法考察根系形态特征,并对根系活力、表面积、伤流量和生物量积累等指标进行测定和分析。结果表明,与单作相比,玉豆带状套作下大豆主根长和侧根长均显著下降,侧根下降81.8%,主根下降42.8%,侧根下降更为明显;根系可溶性糖含量显著下降,导致根系活力降低,伤流量减少;大豆根系表面积和活跃吸收表面积显著减小,降幅均与一级侧根总长度的降幅呈极显著正相关;大豆植株生物量显著下降,其中地下部下降55.2%,地上部下降37.9%,根冠比减小。不同品种(系)大豆根系对套作的响应程度不同,南豆12的主根长、一级侧根长、根体积降幅最小(33.9%、74.4%、65.3%);桂夏3号的根系表面积和生物量降幅最大(67.1%、48.3%);NTS1007则根冠比、根系活力和伤流量冠比降幅最大(35.4%、39.2%、38.9%)。套作遮荫条件下大豆根系的伸长生长比根系生理性状更能够准确地反映植株根系生长状况,根系长度可作为判定对荫蔽胁迫适应能力的一个重要指标。南豆12在玉米-大豆套作下能够更为合理地分配同化产物,减小荫蔽胁迫对根系形态建成和生理活性的抑制作用,保证根系生物量积累。 相似文献
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利用海口市琼山气象站1962～2011年间每年11月到次年4月(以下简称11～4月)的气象资料,运用统计学方法,分析海口市11～4月农业气候资源变化趋势与突变特征,探讨海口市农业气候资源的变化规律。结果表明：(1)海口市11～4月热量资源变得更加丰富,平均气温呈显著的上升趋势,趋势率为0.33℃/10a(P＜0.01),1963年发生突变;各月平均气温均呈正趋势变化;(2)11～4月总降水量存在不明显的下降趋势,趋势率为-15.6 mm/10a(P＞0.1),没有明显的突变点;各月降水量变化趋势不明显,但变率大;(3)11～4月总日照时数呈显著的减少趋势,趋势率为-48.7 h/10a(P＜0.01),2001年发生突变;各月日照时数呈减少趋势,容易造成农作物的光合作用不充分,不利于干物质积累,影响农作物产量;(4)温度上升明显,干燥度增大,气候暖干化,加大干旱发生的强度和频率。气候的变化导致农业气候资源的变化,对农作物产生正负效应,了解农业气候资源的变化特征将对充分利用农业气候资源,科学、合理应对气候变化,趋利避害提供帮助。 相似文献
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不同茶树品种制绿茶贮藏过程中品质变化规律 总被引：1，自引：0，他引：1
为了探明不同茶树品种制绿茶在常温贮藏期间的品质变化规律,以保靖黄金茶1号、保靖黄金茶2号和福鼎大白茶3个茶树品种制成炒青绿茶为材料,密封贮藏于避光室温环境中,分析不同贮藏时间对其品质的影响。结果表明,保靖黄金茶1号、保靖黄金茶2号和福鼎大白茶制绿茶贮藏过程中茶多酚含量（降幅分别为13.96%、15.86%和26.29%）和水浸出物含量（降幅分别为9.81%、10.00%和16.28%）均显著降低,且前两个月降幅较大;氨基酸含量总体下降（降幅分别为20.87%、23.50%和37.94%）,其中贮藏第四个月出现小幅上升;咖啡碱含量前3个月的下降幅度（降幅分别为7.99%、10.82%和13.84%）较大,此后变化幅度减小;叶绿素含量明显下降（降幅分别为15.92%、17.81%和28.49%）;可溶性总糖含量呈现先高后低的波浪形变化,并且香气、汤色、滋味等感官审评指标也有不同程度的下降。三个品种间比较,保靖黄金茶1号、保靖黄金茶2号所制绿茶在贮藏过程中的主要生化成分下降幅度显著低于福鼎大白茶,表现出较好的化学品质特征。 相似文献
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2．2 德国农业产业结构及农产品加工发展特点。2．2．1 德国农业产业结构．2．2．1．1 种植业产业结构。从种植业结构的调整来看，总的趋势是：小麦、玉米和油菜的种植面积扩大。德国统一后，1990—1998年的统计数字表明，玉米种植面积增加最大，为20．5％，其次是小麦和油菜，分别为14．2％和6％；大麦、马铃薯和甜菜的种植呈下降趋势，1990—1998年，大麦种植面积减少最多，减少了14％，其次是马铃薯和甜菜，分别为13％和9．2％。 相似文献
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东北地区是中国大豆的主产区,随着种植年代的推移,东北大豆品种数量不断增多的同时,一些重要农艺性状的演变也呈现出一定趋势。这种趋势反映了人们对于大豆育种选择的倾向以及大豆性状与环境协同的内在联系。因此针对主要性状进行演变分析,对于指导大豆育种研究具有重要意义。本研究收集了1941—2019年东北春大豆区育成的335个大豆品种的主要性状信息,并对其演变过程进行了分析。结果表明：东北春大豆区大豆品种随着年代增加,平均分枝数降低,1940s最高,3.50个,2010s最低,降至0.86个。平均株高在1980s之前呈先降低后升高的趋势,之后平稳上升,2010s最高,为88.20 cm, 1950s最低,为73.50 cm。平均生育期在20世纪70年代最长,为123.86 d,之后整体呈下降趋势,在2010s降至116.67 d。品质性状中,蛋白质含量只在20世纪60～70年代间有所升高,其他相邻年代间均呈下降趋势,在1940s最高,为41.40%,在2010s降至39.48%,平均脂肪含量波动较大,在1940s最高,为21.90%,1990s最低,为20.05%。平均百粒重在1990s最高,达到... 相似文献
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以过热蒸汽为介质常压高温热改性人工林橡胶树木材,处理温度为170、185、200和215℃,处理时间均为3 h。分析了处理温度对热改性橡胶木物理力学性能的影响,结果表明:提高热处理温度,橡胶木的平衡含水率显著降低,降幅为34.33%～62.97%;干缩率显著降低,降幅为3.1%～51.75%(弦向)和2.72%～48.57%(径向);湿胀率显著降低,降幅为37.80%～69.85%(弦向)和28.04%～68.57%(径向);吸水率轻微下降,但不显著;热改性后,橡胶木的尺寸稳定性明显提高。气干密度、全干密度仅在215℃处理时明显下降,其余处理温度变化不显著;弦面硬度先略微增加,后急剧降低,整体呈下降态势;弦、径向局部横纹抗压强度先升高后下降,整体呈增加态势;抗弯强度显著降低,降幅为9.26%～37.52%;抗弯弹性模量有增加,但不显著。 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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Alexander N. Shikov Elena V. Flisyuk Ekaterina D. Obluchinskaya Olga N. Pozharitskaya 《Marine drugs》2020,18(11)
Marine organisms represent an excellent source of innovative compounds that have the potential for the development of new drugs. The pharmacokinetics of marine drugs has attracted increasing interest in recent decades due to its effective and potential contribution to the selection of rational dosage recommendations and the optimal use of the therapeutic arsenal. In general, pharmacokinetics studies how drugs change after administration via the processes of absorption, distribution, metabolism, and excretion (ADME). This review provides a summary of the pharmacokinetics studies of marine-derived active compounds, with a particular focus on their ADME. The pharmacokinetics of compounds derived from algae, crustaceans, sea cucumber, fungus, sea urchins, sponges, mollusks, tunicate, and bryozoan is discussed, and the pharmacokinetics data in human experiments are analyzed. In-depth characterization using pharmacokinetics is useful for obtaining information for understanding the molecular basis of pharmacological activity, for correct doses and treatment schemes selection, and for more effective drug application. Thus, an increase in pharmacokinetic research on marine-derived compounds is expected in the near future. 相似文献
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Résumé
Fusarium culmorum et, dans une moindre mesure,F. avenaceum, F. sambucinum, Colletotrichum coccodes etCylindrocarpon sp. ont été isolés de tubercules entreposés en atmosphère contr?lée (AC) et atteints de pourriture grave. Des expériences
d'inoculation de tubercules avec 10 espèces ou variétés fongiques et conservation en AC à 8 et 10°C ont montré que: 1) les
champignons non pathogènes en atmosphère normale (ex.:Cylindrocarpon sp.) le devenaient en AC, 2) ceux qui étaient faiblement pathogènes en atmosphère normale étaient nettement plus virulents
en AC (ex.:F. culmorum), 3) les espèces ou variétés virulentes en conditions d'air normales (Fusarium sulphureum etPhoma exigua var.foveata) ne provoquaient pas de pourriture plus grave en AC et leur activité pouvait même être légérement freinée.
Summary The extensive rotting of tubers which occurred during storage trials in controlled atmospheres has led to a mycological and pathological study of the rots. The most frequently isolated species wasFusarium culmorum althoughF. avenaceum, F. Sambucinum, Coletotrichum coccodes and aCylindrocarpon sp. were also present. Tubers of cvs Bintje and Ulla were inoculated with 19 isolates of 10 fungal species or varieties associated with rotting of stored tubers (Table 1). The tubers were incubated at 8 or 10°C in normal or controlled (2% O2:1% CO2, 2% O2:6% CO2, 2% O2:12% CO2, 6% O2:6% CO2) atmospheres and the extent of rotting was determined a month later (Tables 2 and 3 and Fig. 2). Species which were weakly virulent in a normal atmosphere (variousFusarium spp. andPhoma exigua var.exigua) were clearly more aggressive in the controlled atmosphere and this was especially evident in the case ofF. culmorum. Species ot pathogenic in a normal atmosphere under experimental conditions (Colletotrichum coccodes, Cylindrocarpon sp.,Phoma eupyrena) caused rotting in the controlled atmosphere. The two species which were virulent in a normal atmosphere (F. sulphureum andP. exigua var.foveata) were also virulent in the controlled atmosphere and in some cases the extent of rotting was even less. As a general rule, rotting caused by weakly virulent fungi was greater in both cultivars in the controlled than in a normal atmosphere.
Zusammenfassung Eine starke F?ulnis von in Kontrotrollierter Atmosph?re gelagerten Kartoffelknollen veranlasste eine mykologische und pathologische Untersuchung. Der am h?ufigsten isolierte Pilz warFusarium culmorum. F. avenaceum, F. sambucinum, Colletotrichum coccodes undCylindrocarpon sp. wurden ebenfalls bestimmt. Neunzehn St?mme von 10 Pilzsorten oder-Arten welche bei Lagerf?ulnis vorkommen (Tab. 1) wurden auf Knollen der Sorten Bintje und Ulla inokuliert. Die Lagerung wurde bei 8 oder 10°C under Normalbedingungen oder kontrollierter Atmosph?re durchgeführt (2% O2:1% CO2, 2% O2:6% CO2, 2% O2:12% CO2, 6% O2:6% CO2). Der F?ulnisgrad (Abb. 1) wurde nach einem Monat bonitiert. Die Ergebnisse sind in den Tabellen 2 und 3 dargestellt und in der Abb. 2 illustriert. Unter in Normalbedingungen nur schwach virulente Arten (verschiedeneFusarien undPhoma exigua var. exigua) waren deutlich aktiver in kontrollierter Atmosph?re. Dies was besonders der Fall fürF. culmorum. Pilze, die im Versuch unter Normalbedingungen nicht pathogen waren (Colletotrichum coccodes, Cylindrocarpon sp., Phoma eupyrena), haben unter kontrollierter Atmosph?re Sch?den verursacht. Hingegen werden die beiden unter Normalbedingungen sehr pathogenen Arten (F. sulphureum undP., exigua var.foveata), durch kontrollierte Atmosph?re wenig beeinflusst. Es wurde sogar in einigen F?llen eine gewisse Verringerung des F?ulnisbefalls beobachtet. Ganz allgemein haben die getesteten kontrollierten Bedingungen die Entwicklung der Pilzf?ulnis an beiden Kartoffelsorten gef?rdert, speziell durch Pilzarten, welche unter Normal-bedingungen wenig Sch?den verursachen.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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Alejandro M. S. Mayer Aimee J. Guerrero Abimael D. Rodríguez Orazio Taglialatela-Scafati Fumiaki Nakamura Nobuhiro Fusetani 《Marine drugs》2021,19(2)
The review of the 2016–2017 marine pharmacology literature was prepared in a manner similar as the 10 prior reviews of this series. Preclinical marine pharmacology research during 2016–2017 assessed 313 marine compounds with novel pharmacology reported by a growing number of investigators from 54 countries. The peer-reviewed literature reported antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral activities for 123 marine natural products, 111 marine compounds with antidiabetic and anti-inflammatory activities as well as affecting the immune and nervous system, while in contrast 79 marine compounds displayed miscellaneous mechanisms of action which upon further investigation may contribute to several pharmacological classes. Therefore, in 2016–2017, the preclinical marine natural product pharmacology pipeline generated both novel pharmacology as well as potentially new lead compounds for the growing clinical marine pharmaceutical pipeline, and thus sustained with its contributions the global research for novel and effective therapeutic strategies for multiple disease categories. 相似文献