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1.
水稻节水保护性耕作栽培的技术效果   总被引:9,自引:0,他引:9  
 研究了水稻田节水保护性耕作栽培技术体系,即采用留茬带状分层旋耕、苗带全层施肥、免除水整地、润田后插秧为技术主体的水稻保护性耕作节水栽培技术的效果。结果显示该技术可以降低稻田土壤的容重,提高稻田土壤的孔隙度和氧化还原电位;由于实施了集中施肥,苗带土壤耕层速效氮、磷、钾含量也得到提高。稻田土壤理化性状的改善,促使水稻根系生长发育良好,从而使地上部表现出生长优势,提高水稻产量。从产量构成因素看,单位面积穗数和千粒重的提高最明显和普遍。  相似文献   

2.
将平坦的稻田改为沟、台相间的方式,台上插秧,沟内保水,既能改善稻田通气性、提高土壤温度,又能有 效提高土壤的氧化还原电位,为水稻提供一个水、肥、气、热协调的生态环境,有利于土壤与大气的气体 交换、减少土壤中有害物质、提高作物光合效率,从而增加干物质积累,提高水稻产量。  相似文献   

3.
采用磷脂脂肪酸(PLFAs)生物标记法,分析了4个以Ⅱ-32A为母本和3个以制5为父本的系列杂交水稻组合在同等栽培条件下根际土壤的微生物群落结构,并探讨其与水稻特性的内在联系,以期为水稻育种和品种改良提供科学依据。结果表明,水稻根际土壤磷脂脂肪酸生物标记丰富,共检测到38种PLFAs,其中完全分布的生物标记有23种,不完全分布的有15种;水稻根际土壤中PLFAs含量细菌真菌放线菌。不同水稻材料根际土壤微生物磷脂脂肪酸生物标记组成结构存在差异。对根际土壤特征磷脂脂肪酸生物标记16:0(细菌)、18:1ω9c(真菌)、10Me17:0(放线菌)、10Me16:0(硫酸盐还原细菌)和16:1ω5c(甲烷氧化菌)比较可知,制5系列组合含量高,最高的为金生优制5,Ⅱ-32A系列组合较低,含量最低的为Ⅱ优797。对PLFAs总量和水稻特性进行Pearson相关分析,结果表明,PLFAs含量与水稻有效穗数和产量呈显著正相关,但与株高呈显著负相关。对水稻根际土壤磷脂脂肪酸生物量总量进行聚类分析发现,Ⅱ-32A系列组合聚为一类,制5系列组合聚为一类,表现出水稻遗传特性在其根际PLFAs上的差异性。研究结果表明,水稻根际土壤微生物群落PLFAs结构丰富,根际土壤微生物群落结构受水稻遗传亲缘关系的影响。  相似文献   

4.
水稻茎部内生细菌及根际细菌与水稻品种特性的相关性   总被引:1,自引:0,他引:1  
为探讨水稻茎部内生细菌和根际细菌群落结构组成及其与水稻品种特性的关系,2008年7月从5个品种水稻茎部和根际土分离内生细菌和根际土壤细菌,并进行脂肪酸鉴定。结果表明,内生细菌有13个种,隶属于9个属,根际细菌有13个种,隶属于10属,两群落的优势菌均为蜡状芽孢杆菌(Bacillus cereus)。以品种为样本,以根际细菌、内生细菌和水稻生物学特征参数为变量,进行相关性分析得到,根际细菌和内生细菌与水稻穗粒数、千粒重、亩产存在正相关;与有效穗呈负相关。  相似文献   

5.
烂泥田由于长期渍水,导致土温低,通气不良。土温低,抑制根的生长,提高水的粘滞度,增加水与养分进入根的阻力,同时降低根细胞的代谢强度。通气不良,土壤中产生的还原物质积累过多,稻苗呈现枯黄,稻根发黑,严重影响了水稻根的活力。另外,通气不良,土壤空气中氧的含量低,氧的分压小,和它相平衡的土壤溶液中氧的浓度也相应较低,这些使烂泥田处于还原状态,氧化还原电位低,还原物质含量高,不利水稻生长,导致产量低。烂泥田采用垅畦  相似文献   

6.
机插秧与麦秸秆全量还田相结合已成为江苏省水稻生产的主推技术。但机插秧秧苗素质弱,生产上普遍存在缓苗期长、分蘖发生迟等问题。传统的稻田整田方式主要为水耕水耙,翻耕、泡田过于频繁,土壤通透性差,不利于幼苗早发根、早分蘖。采用旱耕旱耙方式有利于减轻这一问题。关于旱整方式对秸秆全量还田条件下机插水稻茎蘖动态、产量形成、根系及土壤有关性状影响的研究极少。为此,笔者在上海农场、江苏五图河农场,研究了麦秸秆全量还田条件下不同整田方式对机插水稻镇稻99上述性状的影响。结果表明,旱整田茎蘖动态年度间有一定差异,高峰苗与水整田相近,但成穗率高于水整田;旱整田产量高于水整田,平均增产8.36%。旱整田单位面积有效穗数多,每穗粒数少,结实率较高;旱整田抽穗期、灌浆结实中期的叶面积系数高于水整田,中、后期光合面积明显增加,单位面积颖花量高于水整田;旱整田抽穗期、成熟期干物质生产量、经济系数均大于水整田,结实期茎鞘叶干物质比重降幅小于水整田;旱整田有利于水稻根系生长,主要生育时期水稻单丛不定根数多、单丛根干质量大,有利于前期分蘖的发生,也有利于延缓后期叶片衰老,提高光合功能;旱整田有效提高了土壤氧化还原电位,降低了土壤含水率,改善了土壤的通透性。  相似文献   

7.
寒地水稻垄作覆膜半旱式栽培技术研究   总被引:1,自引:0,他引:1  
水稻常规栽培法,由于稻田长期滞水而处于较强的还原状态,使土壤理化性质恶化导致水稻根系发育不良,直接影响了水稻的生长发育,是育难以提高。垄作覆膜半旱式栽培则有效地解决了这一问题。主要表现在①通过垄作扩大地表面积,提高光能利用率,增加地温。覆膜后日均土温比常规增加3.2-6.2℃;②通过垄体覆光解膜减少地表水份蒸发,利用节水、保温灭草;③通过垄体夹心肥(基、蘖肥一次深施)可提高肥料利用率25%-30%,并促进水稻根系下扎;④通过半旱式(半沟水)节水灌溉,改善土壤氧化还原条件,活化土壤的潜在肥力,尤其在水稻生育前期速效磷、钾、水解N明显提高,使水稻根系生长旺盛,粗壮且白根多,根量高于对照1倍;反映在地上部,植株分蘖明显增加,个体发育健壮,有效叶面积增加,收获穗数增多,增产26.7%-44.9%。  相似文献   

8.
水稻常规栽培法 ,由于稻田长期滞水而处于较强的还原状态 ,使土壤理化性质恶化导致水稻根系发育不良 ,直接影响了水稻的生长发育 ,产量难以提高。垄作覆膜半旱式栽培则有效地解决了这一问题。主要表现在①通过垄作扩大地表面积 ,提高光能利用率 ,增加地温。覆膜后日均土温比常规增加 3 2~ 6 2℃ ;②通过垄体覆光解膜减少地表水份蒸发 ,利于节水、保温灭草 ;③通过垄体夹心肥 (基、蘖肥一次深施 )可提高肥料利用率 2 5%~ 30 % ,并促进水稻根系下扎 ;④通过半旱式 (半沟水 )节水灌溉 ,改善土壤氧化还原条件 ,活化土壤的潜在肥力 ,尤其在水稻生育前期速效磷、钾、水解N明显提高 ,使水稻根系生长旺盛 ,粗壮且白根多 ,根量高于对照 1倍 ;反映在地上部 ,植株分蘖明显增加 ,个体发育健壮 ,有效叶面积增加 ,收获穗数增多 ,增产 2 6 7%~ 4 4 9%  相似文献   

9.
香蕉园土壤活性微生物的测定   总被引:1,自引:0,他引:1  
采用间接计数法测定华南热带农业大学环植学院教学基地香蕉园土壤活性微生物中的放线菌、硝化细菌、亚硝化细菌、反硝化细菌数量。通过比较分析可知,香蕉园土壤放线菌数量表现为根际〉非根际〉根面;硝化细菌和亚硝化细菌数大小为非根际〉根际〉根面;而反硝化细菌数大小为根际〉根面〉非根际。  相似文献   

10.
以根瘤超着生大豆突变体0498和完全不结瘤的大豆突变体0701为材料,在人工气候室内模拟大气CO2浓度倍增以及UV-B辐射增强的复合逆境胁迫条件,研究其对大豆根际氨氧化细菌数量和根际土壤酶活的影响。结果表明:与对照相比,CO2浓度倍增能显著提高大豆根际氨氧化细菌的数量,增加土壤中脲酶、转化酶、酸性磷酸酶和碱性磷酸酶的活性,对完全不结瘤的0701影响更加显著;UV-B辐射增强对氨氧化细菌数量无显著影响,对土壤酶活存在一定的抑制作用。超量根瘤的存在,使CO2倍增和UV-B辐射增强对上述指标的影响得到一定的缓解。  相似文献   

11.
12.
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   

13.
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   

14.
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   

15.
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   

16.
Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.  相似文献   

17.
Evolutionary aspects of the trade-off between seed size and number in crops   总被引:1,自引:0,他引:1  
Victor O. Sadras   《Field Crops Research》2007,100(2-3):125-138
Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.  相似文献   


18.
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   

19.
SUMMARY

Vitamin A, iodine, and iron deficiencies affect large numbers of people worldwide. A deficiency of one or more of these micronutrients adversely affects the physical and mental abilities of humans. South Asia contains a high percentage of these individuals, not just because of its large population, but also the prevalence of deficiency is higher there than in many other parts of the world. The reasons for the high rates of deficiency in South Asia are many, but they include inadequate availability of micronutrient-rich foods, sub-optimal dietary habits, and high rates of infection. Across the region, national plans vary from (a) increasing availability of appropriate foods, (b) introducing new dietary behaviors, (c) improving health status, and (d) directly addressing deficiency through intervention programs. The extent to which each of the countries is making progress toward the goals of these plans can help in understanding the priorities for future efforts to address micronutrient malnutrition. This article discusses the adverse effects of micronutrient deficiencies in humans with special reference to South Asia.  相似文献   

20.
Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.  相似文献   

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