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稻蟹共作模式生态效应研究进展 总被引：3，自引：0，他引：3
主要从土壤、水环境和杂草防控三个方面,对目前我国稻蟹共作模式下田间生态的研究现状进行了总结与分析.提出了几种目前比较常见的稻蟹共作模式,即有机稻蟹和常规稻蟹两种普遍模式.分析了稻蟹共作对土壤理化性质、土壤酶活性和根际微生物区系的影响.养蟹稻田可以显著降低土壤容重,而总孔隙度及全氮、全磷、碱解氮、有效磷、速效钾和土壤有机质含量都显著增加;显著提高0~10 cm土壤脲酶、蛋白酶、脱氢酶以及过氧化氢酶的活性;土壤根际微生物以细菌为主要菌群,氨化细菌、反硝化细菌、嫌气性纤维素分解菌、好气性自生固氮菌、亚硝酸细菌数量显著高于单作水稻;与常规稻蟹相比,有机稻蟹的土壤性状表现更好.稻蟹模式下浮游动植物的多样性和生物量显著低于单作水稻,而水体中溶解氧(DO)明显偏低,硝酸盐、磷酸盐含量显著高于不养蟹稻田.稻田养蟹能够显著抑制稻田4种优势杂草的密度,对于稻田杂草的防控效果明显. 相似文献
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土壤酶活性是表征土壤肥力水平和养分转化的重要指标,揭示种植模式和季节变化对茶园土壤酶活性影响,阐明影响茶园土壤酶活性变化的主要环境因子,为合理评估有机茶种植的土壤生态效应提供理论依据。结合野外调查和室内分析方法,以武夷山茶区3种类型样地,即林地（FD）、常规茶园（CT）和有机茶园（OT）为研究对象,测定了参与土壤碳、氮和磷循环的6种酶活性,研究不同种植模式下土壤酶活性的季节变化规律及影响因子。结果显示,与林地土壤相比,常规种植模式茶园土壤铵态氮、全磷、有效磷和有效钾含量显著增加,土壤全钾和pH显著降低;相比常规茶园,有机茶园土壤有机质和全氮含量显著增加,土壤全磷、有效磷、全钾和速效钾含量显著降低,土壤pH有所增加,土壤养分比例更为协调。种植模式和季节及其交互作用对土壤脲酶和过氧化氢酶活性影响显著。与林地土壤相比,常规茶园土壤脲酶、多酚氧化酶、过氧化氢酶和酸性磷酸酶活性下降了12.05%～63.55%,有机茶园土壤脲酶显著提高了324.95%,种植模式并未改变土壤硝酸还原酶活性。总体而言,夏秋季节（5月和8月）土壤脲酶、多酚氧化酶、蔗糖酶和酸性磷酸酶活性明显高于冬春季节（11月和2月）,... 相似文献
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有机无机复混肥对大豆根际环境的影响 总被引：1，自引：0，他引：1
在典型的酸化黑土上,研究了有机无机复混肥不同施入量对大豆根际土壤pH值、细菌、真菌及放线菌含量的影响.结果表明:有机无机复混肥可以大幅增加土壤中细菌、真菌和放线菌的数量,其中细菌数量增加幅度最大,从52×106·g-1增加到154×106·g-1;同时施加复混肥还能提高土壤的pH值(从5.84到6.25)和大豆固氮菌的活性进而改善土壤的理化性质;此外,施加复混肥还可以增加速效氮和速效钾等营养成分的释放从而使土壤的营养水平得到明显改善,最终导致大豆产量的增加. 相似文献
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遮阴对抹茶茶园土壤微生物特性及土壤酶活性的影响 总被引：1，自引：0，他引：1
分析了遮阴对浙江省抹茶主产区茶园土壤微生物特征以及土壤养分和酶活性变化情况。结果表明,抹茶茶园遮阴后0~20cm土层有机质、全氮、水解氮、全磷、有效磷和有效钾含量较未遮阴茶园增加,达到显著水平。遮阴茶园土壤的有机质含量达49.81g·kg^-1,显著高于未遮阴茶园土壤32.50g·kg^-1(P<0.05)。茶园遮阴后可以显著提升土壤脲酶、蔗糖酶、土壤蛋白酶、酸性磷酸酶和碱性磷酸酶的活性(P<0.05)。遮阴茶园细菌、真菌等多样性指数和基因型丰富度也高于未遮阴茶园。遮阴可以提升抹茶茶园土壤营养元素含量以及与土壤养分转化密切相关的几类酶的活性,增加表层土壤微生物的数量和活性,有利于受损茶园土壤生态系统的恢复和重建,全面提升土壤质量。 相似文献
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研究了三种产量水平的红壤茶园土壤酶活性在剖面上的变化。结果表明,除蛋白酶活性外,其余酶活性从表层到底层是逐渐下降的。土壤脲酶、多酚氧化酶及过氧化氢酶活性与土壤酸度、有机质及速效养分含量有显著或极显著相关性。 相似文献
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枯草芽孢杆菌对植烟土壤养分含量与酶活性的影响 总被引：2，自引：0，他引：2
为探讨枯草芽孢杆菌微生物菌剂对土壤主要养分含量及酶活性的影响,以及施用枯草芽孢杆菌后的土壤养分与酶活性间的关联性,以K326为材料,开展了枯草芽孢杆菌微生物菌剂不同用量研究。结果表明:烤烟移栽以后,(1)土壤有机质含量呈现下降趋势;碱解氮和有效磷、钾含量则呈现"低-高-低"的变化规律,且烤烟移栽后45 d达到最大值;(2)土壤脲酶活性呈现由低到高的变化,移栽后90 d达到最大值;过氧化氢酶活性呈现"低-高(60 d)-低-较高(90 d)"的规律性变化;蔗糖酶活性出现"较高-低(60 d)-高(75 d)-高(90 d)"的规律性变化;(3)通过土壤酶活性对土壤有机质、碱解氮和速效磷、钾含量间的灰色关联分析表明,土壤脲酶活性在移栽后45 d对有机质和碱解氮,以及移栽后60 d对速效磷和钾含量影响最大;过氧化氢酶和蔗糖酶活性,分别在移栽后60 d和75 d,对土壤有机质、碱解氮,及速效磷和钾的含量影响最大。植烟土壤施用枯草芽孢杆菌,对提高土壤养分含量及酶活性有着良好的效果,不同生长阶段土壤养分与酶间相互作用有差异。 相似文献
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本文在几年试验研究分析的基础上,对大豆连作不同年限不同生育期中脲酶、酸性磷酸酶、过氧化氢酶、转化酶的酶活性与土壤肥力因素之间的相关性进行了研究.分析结果表明,4种酶的酶活性与有机碳、土壤pH值以及4种酶活性之间都存在着显著的正相关.脲酶活性与速效钾呈显著的正相关;与速效磷呈负相关.酸性磷酸酶活性与速效钾呈正相关.过氧化氢酶活性与水解氮呈显著的正相关,与速效钾呈正相关,与速效磷呈显著的负相关.从大豆连作土壤中4种酶活性与土壤肥力因素之间的相关性分析可以看出,土壤的农化性状影响着土壤酶活性的高低,而土壤酶活性的变化也影响着土壤有效肥力的高低,它们之间的关系是相互影响、相互制约的.由此可见,用土壤酶活性来表征土壤生物学活性和土壤有效肥力状况,并根据酶活性评价土壤肥力水平指标是可行的. 相似文献
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蚯蚓生物有机培肥技术(FBO)对茶园土壤微生物特征及酶活性的影响 总被引：3，自引：0，他引：3
连续5年对蚯蚓生物有机培肥的茶园土壤微生物特征以及酶活性变化情况进行了研究,分析了蚯蚓生物有机培肥技术(FBO)对茶园土壤微生物特征及酶活性的影响。结果表明,蚯蚓生物有机培肥处理(100% FBO)可以显著增加0~20 cm土层微生物量碳、呼吸速率、微生物熵、细菌、真菌和放线菌等表征土壤微生物数量和活性的指标,并可以显著提升过氧化氢酶、脲酶、转化酶和碱性磷酸酶的活性(P0.05)。在20~40 cm土层,100%FBO处理的微生物和酶活性相关指标也高于CK,但多数未达到显著水平。蚯蚓生物有机培肥技术可以显著增加表层土壤微生物的数量和活性,并提升与土壤养分转化密切相关的几类酶的活性,有利于受损茶园土壤生态系统的恢复和重建,全面提升土壤质量。 相似文献
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Emile W. Hellendoorn 《Plant foods for human nutrition (Dordrecht, Netherlands)》1979,29(1-2):227-244
Leguminous seeds form a valuable contribution for the daily protein need of people living in the poorer countries. The protein of cereals and the protein of pulses have a complementary effect, resulting in an improved protein quality of the mixtures. This effect is maximal for a protein ratio of about 1∶1. In the diet of many people this ratio is not attained, cereal protein remaining far in excess. It is not likely that the cause of the sub-optimal consumption of pulses has to be sought in some impairing factor present in the seeds themselves. During storage cooking quality and protein qualyti decrease. Probably the availability of methionine and cystine diminishes during storage. In addition, the susceptibility of bean starch for pancreatic amylolysis decreases. The flatulence activity of beans is not caused by the galacto-oligosaccharides only. They form a minor part of the indigestible components (dietary fibre) of leguminous seeds, all of which are fermented in the large intestine, developing gas. Fermentation of the indigestible residue of beans also gives rise to the formation of volatile fatty acids which stimulate peristalsis, resulting in shorter transit times of the food through the intestine. Pulses, when present in the daily diet in appreciable amounts, have a lowering effect on the blood cholesterol level. 相似文献
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Zea mays oil is of oestrogenic activity as it produced vaginal cornification in rats and mice and uterine growth in rats. The effect of 0.1 ml of the oil corresponded to that of 0.1 µg of oestradiol monobenzoate.
Zusammenfassung Das Öl vonZea mays besitzt oestrogene Wirkung und ruft vaginale Cornification bei Ratten und Mäusen hervor und bewirkt bei Ratten Wachstum des Uterus. Die Wirkung von 0,1 ml des Oels entspricht derjenigen von 0,1 µg von Oestradiol-Monobenzoat.
Résumé L'huile deZea mays possède l'activité oestrogénétique et produit cornification du vagin chez rats et souris. L'effet de 0,1 ml de cette huile correspond a celui de 0,1 µg de l'oestradiol- monobenzoate.相似文献
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Osmont KS Arnt CR Goldman IL 《Plant foods for human nutrition (Dordrecht, Netherlands)》2003,58(1):27-40
Organosulfur compounds in onion extracts are formed following thelysis of the S-alk(en)yl-L-cysteine sulfoxides by alliinase. Thesecompounds inhibit the aggregation of human blood platelets and offer thepotential for positive cardiovascular health benefits. An experiment wasdesigned to examine temporal and temperature effects on onion-inducedantiplatelet activity. Platelet aggregation is induced by various agonists,including ADP, collagen, and thrombin. Unexpectedly, all freshly-juicedonion extracts (ca. 5 minutes post-juicing) appeared to exhibit both anagonist-free aggregation peak (AFP) and a platelet inhibitory peak (PIP)characteristic of inhibition of platelet aggregation. The AFP was minimalby 30 minutes and dissipated in all treatments by 120 minutes, whilethe PIP increased as onion extracts aged and did not change after 30minutes at 25 °C. This finding confirms the observation that the in vitro platelet inhibitory activity of onion organosulfur compounds istime dependent. Freshly-prepared onion extracts were incubated with theADP scavenger enzyme apyrase (E.C. 3.6.1.5). AFPs were abolished inapyrase-treated extracts, suggesting that this response may have been dueto free ADP in onion extracts, although an amount of ADP required togenerate such a response would be unexpected in onion extracts. Inaddition, platelet aggregates were not observed in the AFP, suggesting thisresponse may be associated with changes in light transmission throughplatelet rich plasma that are not associated with platelet aggregation.Artifacts of analysis are, therefore, possible when assessing onion-inducedantiplatelet activity with freshly-juiced extracts. Temporal formation ofplatelet-inhibiting organosulfur compounds should be taken into accountduring both in vitro and in vivo assessment of onion-inducedantiplatelet activity. 相似文献
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Antioxidant activity of Hawaiian marine algae 总被引：1，自引：0，他引：1
Marine algae are known to contain a wide variety of bioactive compounds, many of which have commercial applications in pharmaceutical, medical, cosmetic, nutraceutical, food and agricultural industries. Natural antioxidants, found in many algae, are important bioactive compounds that play an important role against various diseases and ageing processes through protection of cells from oxidative damage. In this respect, relatively little is known about the bioactivity of Hawaiian algae that could be a potential natural source of such antioxidants. The total antioxidant activity of organic extracts of 37 algal samples, comprising of 30 species of Hawaiian algae from 27 different genera was determined. The activity was determined by employing the FRAP (Ferric Reducing Antioxidant Power) assays. Of the algae tested, the extract of Turbinaria ornata was found to be the most active. Bioassay-guided fractionation of this extract led to the isolation of a variety of different carotenoids as the active principles. The major bioactive antioxidant compound was identified as the carotenoid fucoxanthin. These results show, for the first time, that numerous Hawaiian algae exhibit significant antioxidant activity, a property that could lead to their application in one of many useful healthcare or related products as well as in chemoprevention of a variety of diseases including cancer. 相似文献
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Summary Amylase activity in extracts of sprouted tubers was optimised at final concentrations of soluble starch in the incubation
medium of 0.6–2.0 mg cm−3. Optimum pH was 6. The exclusion of calcium ions from extraction and incubation media did not result in reduced enzyme activity.
This, together with a shift in the absorption maximum of the starch-iodine complex almost identical to that observed with
pure β-amylase, indicates the predominance of β-amylase in the extracts. Over a 15-min incubation period the linearity of
the response was dependent upon the volume of tuber extract included in the assay medium. Gel filtration of extracts did not
influence this response. 相似文献
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Manoj G Thampi BS Leelamma S Menon PV 《Plant foods for human nutrition (Dordrecht, Netherlands)》2001,56(1):13-21
The effects of fiber isolated from black gram (Phaseolus mungo) and Coconut (Cocos nucifera) kernel on the metabolic activity of intestinal and fecal beta glucuronidase activity during 1,2-dimethylhydrazine induced colon carcinogenesis were studied. The results indicated that the inclusion of fiber from black gram and coconut kernel generally supported lower specific activities and less fecal output of beta-glucuronidase than did the fiber free diet. This study suggests that the fibers isolated from coconut or black gram may potentially play a role in preventing the formation of colon tumors induced by the carcinogen 1,2-dimethylhydrazine by reducing the activity of the intestinal as well as fecal beta-glucuronidase. 相似文献
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大豆萌发过程中谷氨酸脱羧酶活性变化研究 总被引：1，自引：0，他引：1
研究了大豆在浸泡、萌发两个过程中谷氨酸脱羧酶(GAD)的活力变化。通过测定大豆中γ-氨基丁酸(GABA)的含量变化,间接测定大豆中GAD的活性。结果表明,大豆在25℃,浸泡10h,大豆中的GAD活性达到浸泡中最高水平,酶活性为2.45U。浸泡后的大豆在30℃,萌发40h时,酶活性达到萌发中最高水平,为1.28U。大豆在浸泡和萌发两个状态下,GAD活性较储藏期都有很大提高,且浸泡时酶活总体水平高于萌发期酶活总体水平,其中大豆GAD在25℃,浸泡10h时活性最高,为2.45U。 相似文献
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Viveros-Valdez E Rivas-Morales C Oranday-Cardenas A Verde-Star MJ Carranza-Rosales P 《Pakistan journal of biological sciences: PJBS》2011,14(4):305-307
Hedeoma drummondii is a medicinal plant with diverse properties; however, validations of its medicinal uses are scarce. To evaluate its antimicrobial properties H. drummondii, was tested against opportunistic pathogens of medical importance. Antimicrobial tests were performed by the microdilution method in order to determine the Minimal Inhibitory Concentration (MIC) for each extract. Extracts of this plant showed relevant antimicrobial activity, results revealed that the hexanic extract has stronger activity and broader spectrum compared to acetone and methanol extracts. The activity of hexanic extract may be attributed mainly to the presence of the monoterpenes pulegone and menthol. In conclusion, the hexanic extract possess relevant antibacterial properties which suggests that H. drummondii have bioactive principles; these new data provide scientific support for the use of this plant in traditional medicine, particularly for gastrointestinal diseases. 相似文献