棕色固氮菌分离鉴定与初步应用研究

棕色固氮菌分离鉴定与初步应用研究结果表明,通过分离培养和鉴定,分离出的6个棕色固氮菌贵州地方株,其中4株有一定固氮能力,另外2株固氮能力较强。应用棕色固氮菌制成菌肥,可以显著提高黑麦草产量。     

某些因子对四株维氏固氮菌菌株合成海藻酸的影响

本试验结果表明:相同条件下,四株维氏网氮菌(Azotobacter vinelandii)中,以菌株N_(13)的发酵周期短(1～2天),海藻酸合成最大(5.82 g/L),产海藻酸活力强(活力系数为2.60);不同条件下,菌株N_(13)在所试菌龄内,海藻酸合成最均高于其他菌株,其一天菌龄的浓度高达5.45±0.43 g/L,不同发酸液的海藻酸合成最仅在pH 8.0时低于菌株14~#,尤以pH6.0时,高达8.61g/L.在旋转式摇床或往复式摇床上,亦以菌株N_(13)的海藻酸合成量最高(3.61±0.26 g/L和4.39±0.12 g/L),试验温度范围内,也以菌株N_(13)的海藻酸合成量最高,32℃时达到最大值(6.41 g/L),菌株N_(13)以2～8％(V/V)的接种量试验表明:旋转式摇床为2％,往复式摇床为2～4％。     

生物复合菌肥“地霸”的菌群分离鉴定及生物学特性的初步研究

对生物复合菌肥进行菌群的分离鉴定、含菌量的测定和比较以及菌株生物学特性的初步研究.该生物复合菌肥中含有活性较高的固氮菌(维氏固氮菌)、钾细菌和无机磷细菌,每克菌肥中细菌总数达到2.0亿～2.5亿.固氮菌在修改的Dobereiner无氮培养基上生长良好,固氮活性较强,该菌生长最适温度在20～32℃之间,生长的pH值范围是5.5～8.5,最适pH值是7.5.     

大豆初花期施氮肥效果的研究

中等肥力的土壤上栽培大豆、接种高效的根瘤菌株后,在大豆初花期追施少量氮肥,既能充分发挥根瘤菌的共生固氮作用,又可补充大豆生育后期根瘤固氮和土壤供肥的不足,满足果荚发育过程中对氮素营养的高需求,达到提高产量之目的。试验表明,初花期每亩施3公斤尿素(45公斤/公顷),保证大豆后期的良好生长和发育,促进对氮、磷肥的吸收利用,增加了植株和籽实中氮、磷的含量,提高了大豆的品质和营养价值,增产显著,每亩增产24.4公斤大豆(366公斤/公顷),经济效益高。     

Uptake and continued metabolic activity of azotobacter within fungal protoplasts

Uptake of vegetative cells of Azotobacter vinelandii into protoplasts of the mycorrhizal fungus Rhizopogon sp. can be induced by treatment with polyethylene glycol (molecular weight, 6000). An L-form of the bacteria has been selected for within the differentiated fungal mycelium which is capable of acetylene reduction and nitrogen fixation, as confirmed by nitrogen-15 assays; this allows the fungus to grow on media lacking any combined nitrogen. The fungus grows and reduces acetylene on concentrations of antibiotics that prevent the growth and activity of free-living Azotobacter. Electron microscopy has revealed modified mitochondrial forms or included bacterial L-forms surrounded by an extra fungal membrane within the hyphae of the modified strains. Poly-beta-hydroxybutyric acid, a storage product of Azotobacter cysts, has also been identified in the hyphae. This would appear to be the first report of the transgenosis for acetylene reduction activity and nitrogen fixation into a eukaryote cell.     

白腐真菌的辐射诱导及酶学性质的研究

选用菌株为白腐真菌5.132 Fomes Lignosus(Berk)Coke,为进一步提高白腐真菌漆酶活性和对木质纤维素的降解能力,采用60Co-γ射线对白腐真菌孢子悬浮液辐射处理,分析原菌株和辐射菌株,以及不同碳源和氮源浓度对漆酶和菌丝生长的影响.结果表明,在不同碳源条件下,糊精产酶量最高,漆酶活力达到6.28 U·mL-1,诱变株比对照株漆酶活力提高5.44%.不同氮源条件下,牛肉蛋白胨产酶量最高,漆酶活力达到4.65 U·mL-1,诱变株比对照株漆酶活力提高7.02%;在不同碳源条件下,可溶性淀粉菌丝干重最高,达到0.68 g· L-1,诱变株比对照株提高了21.86%.不同氮源条件下,牛肉蛋白胨菌丝干重最高,达到2.98 g·L-1,诱变株菌丝干重比对照组提高21.06%;同一碳源不同浓度的比较试验中,低浓度碳源提高酶产量,高浓度碳源提高菌丝生长量,同一氮源不同浓度的比较试验中.其结果与碳源试验结果一致;在不同碳源和不同氮源条件下,60Co-γ射线辐射白腐真菌后,漆酶活力极显著提高(P<0.01),而菌丝干重差异不显著(P>0.05).     

水稻根系分离菌泌氨菌株的筛选试验

本试验采用Burris推荐的氨微量扩散法,从309个水稻根系分离菌株中筛选具有泌氨特性的固氮菌自然突变菌株。初步试验结果表明,培养基以含氮较低的每升加0.1克酵母膏的慢型快长培养基较为适宜。供试菌株中大部分没有泌氨作用,并能消耗培养基中的氮源。发现维涅兰德固氮菌230(Azotobacter uinelandii)菌株的泌氨作用较强,其泌氨量为固氮量的2.05％。该菌在以前的长期试验中尚未注意到有泌氨特性。属于德氏固氮菌属(Derxia)的“卷4”菌株也具有泌氨作用,但固氨量较低,只有固氮量的1.18％。     

4种除草剂对紫花苜蓿-根瘤菌共生固氮的影响

在室内条件下,研究了乙羧氟草醚、三氟羧草醚、乙草胺和异丙甲草胺等4种除草剂对紫花苜蓿-根瘤菌共生固氮的影响。结果表明:4种除草剂均能对紫花苜蓿-根瘤菌共生固氮产生一定的抑制作用,其中以乙羧氟草醚的抑制作用最强,在高剂量下鲜重抑制率和干重抑制率分别为68.5%,70.6%,与对照植株的结瘤率和总含氮量92%和2.620%相比,其结瘤率和总含氮量为31%和0.072%;异丙甲草胺的抑制作用最弱,高剂量下鲜重抑制率和干重抑制率分别为18.5%和26.8%,与对照植株的结瘤率和总含氮量94%和2.136%相比,其结瘤率和总含氮量为60%及0.482%;紫花苜蓿经四种除草剂不同剂量处理后,总含氮量远远低于对照植株的总含氮量。     

不同施肥和耕作方式下强化栽培水稻的生长与氮素利用

研究了不同施肥和耕作方式下强化栽培水稻的生长及氮素利用。结果表明,免耕条件下以尿素 猪粪强化栽培水稻的产量最高,而常耕条件下以单施尿素常规栽培水稻的产量最高,但各处理的产量差异并不显著。无论是免耕还是常耕条件下,单施尿素常规栽培水稻比单施猪粪强化栽培水稻植株积累更多的氮素量,但其氮素稻谷生产效率、氮素收获指数下降。两种耕作方式比较,免耕条件下水稻的氮素运转效率、氮素农艺效率显著高于常耕,但常耕条件下的氮素回收效率比免耕的高127.95%,差异显著。     

Analysis of plant nutrient management strategies: Conventional and alternative approaches

During times of economic uncertainty, such as the current period, all costs of agricultural production become important and worthy of close scrutiny if the threat of farm foreclosures is to be minimized. This concern particularly applies to the cost of plant nutrients, which, under conventional approaches, typically represents 24%–30% (or more) of the total variable costs of production [Lu et al. (2000) Food Reviews International 16(2): 121–157; Bullen and Brown (2001) Economic Evaluation of UNR Cotton, NC State University, Raleigh, North Carolina]. The purpose of this paper is to examine, via a review of the literature, the economics and profitability of various plant nutrient management strategies–both conventional and alternative ones–in an attempt to identify those strategies that can lead to financial resource optimization and, ultimately, maximum profits for farm enterprises. The results of this analysis are as follows: In a meta-analysis of 120 studies, conventional nutrient management systems, using commercial fertilizers, showed higher profit for most grain crops (with the exception of corn and sorghum), than organic nutrient management systems. Both cover crop and animal manure-based systems show considerable promise as alternative nutrient management strategies for increasing farm profitability. A cover crop system produced the highest average corn yield and gross margin per hectare with the smallest coefficient of variation compared to no-tillage conventional, manure-based, or crownvetch systems. Manure-based systems that do not require purchase or transport of the manure (as in combined animal and crop production systems) can be considerably more profitable than conventional systems. Both manure-based and cover crop systems that do not include the use of commercial fertilizers (i.e., organic systems), hold particular promise due to the output price premiums typically garnered by the organic crops grown under such conditions.     

氮肥减量下长期间作毛叶苕子根茬还田对玉米产量及氮肥利用率的影响

【目的】 通过探讨氮肥减量条件下长期间作毛叶苕子利用其根茬还田对玉米产量及氮肥贡献率的影响,旨为玉米毛叶苕子间作体系的氮肥替代及其氮素资源管理提供科学依据。【方法】 试验于2014—2019年在农业农村部甘肃耕地保育与农业环境科学观测实验站进行。采用田间试验方法,在不施肥（CK）和习惯施氮（N₁₀₀）水平下设置单作玉米处理,在90%（N₉₀V）、80%（N₈₀V）、70%（N₇₀V）、60%（N₆₀V）和0%（N₀V）的习惯施氮水平下设置玉米毛叶苕子间作处理,共7个处理,3次重复,田间随机区组排列。研究不同氮肥减施条件下,玉米长期间作毛叶苕子后,作物产量、经济效益、氮肥偏生产力、氮肥农学效率和氮肥贡献率的变化规律。【结果】 玉米长期间作毛叶苕子利用根茬还田对玉米具有明显的增产优势,而且这种增产优势随间作年限的延长呈增加趋势。相比习惯施氮处理（N₁₀₀）,在化学氮肥减施20%条件下玉米长期间作毛叶苕子根茬还田,可以在保证玉米稳产的情况下增收2 273.2 kg·hm^-2毛叶苕子干草,合计收益增加0.9%,达29 686元/hm²,同时,氮肥偏生产力和农学效率显著提高20.7%和14.7%;在化学氮肥减施30%的条件下玉米长期间作毛叶苕子根茬还田,虽然玉米籽粒产量降幅明显,达7.7%,但是因为可以增收2 319.34 kg·hm^-2毛叶苕子干草,合计收益与习惯施氮处理持平,达28 652元/hm²,同时,氮肥偏生产力和农学效率显著提高31.8%和16.3%;在化学氮肥减施40%的条件下玉米长期间作毛叶苕子根茬还田,虽然可以增收2 303.09 kg·hm^-2毛叶苕子干草,氮肥偏生产力和农学效率也显著提高48.8%和23.8%,但是因为玉米籽粒产量显著降低10.7%,合计收益只有27 929元/hm²,显著低于习惯施氮处理。【结论】 在甘肃河西绿洲灌区玉米生产过程中,氮肥减量条件下长期（9年）间作毛叶苕子利用其根茬还田,若只考虑玉米籽粒产量,则可以替代20%的化学氮肥用量,若考虑玉米和毛叶苕子的合计产值,则可以替代30%的化学氮肥用量。     

低氮条件下间作大豆对宿根蔗内生固氮菌固氮酶活性、氮素积累及产量的影响

【目的】探讨低氮条件下间作大豆对宿根蔗内生固氮特性及生长的影响,为生产上合理应用甘蔗/大豆间作提供理论依据。【方法】采用裂区试验,以单、间作不同种植模式为主因素,以ROC22、B8和GT213个甘蔗品种为副因素,比较低氮条件下不同处理间甘蔗的产量、氮素积累及内生固氮菌固氮酶活性的差异。【结果】低氮条件下,与甘蔗单作处理相比,甘蔗/大豆间作处理的宿根蔗茎径、有效茎数和产量分别提高5.1%~8.7%、7.9%~31.0%和9.0%~40.5%,而不同处理间的株高没有明显差异。间作处理可显著提高宿根蔗的茎、叶内生固氮菌固氮酶活性,其中ROC22茎、叶中的固氮酶活性增幅最大,分别提高了59.35和0.98~1.89 nmol C2H4/gFW·h。除分蘖期间作处理B8叶片的全氮含量和GT21的氮素总积累量显著提高18.8%和35.2%外(P<0.05,下同),其他品种叶片的全氮含量和氮素积累量在处理间差异不显著(P>0.05);伸长期时,间作处理下蔗茎的全氮含量和氮素积累量均较单作有不同程度提高,其中ROC22和GT21的氮素总积累量分别显著提高35.0%和81.1%。【结论】低氮条件下,间作大豆可明显提高宿根蔗的内生固氮菌固氮酶活性、氮素积累及产量,其中以GT21间作大豆的增产效果最佳。     

Effect of Inoculation Rhizobium and Response of Soybean-Rhizobium System to Insoluble Phosphate

In order to produce efficiently symbiotic system in acid soils which could be used for the recovery of insoluble phosphate soil and improvement of the fertility,etc.,host range of Rhizobium was isolated from the root nodules of wild and cultivated soybean varieties growing in south China,evaluated the effects of Rhizobium on enhance nitrogen fixing activities,phosphorus(P),nitrogen (N)uptakes,growth and yield of soybean under pot and field conditions.The results showed that combined Rhizobium inoculation was more effective than individual Rhizobium inoculation. The combined Rhizobium of CW54 strains had the highest effect, nodule number, nodule weight and nodule nitrogenase activity were markedly stimulated as compared to those of the control U110, respectively. The nitrogen contents in the plants treated with CW54 strains were significantly increased by 43.2% as compared to those of the control U110 in Al-P soil, but statistical significance was not observed in Fe-P soil. By contrast, inoculation with CW54 significantly enhanced phosphorus uptake of plant in Fe-P soil than that in Al-P soil. The effects of inoculation of CW54 strains in a field condition were similar to those of in a pot condition. The total biomass and yield in the plants treated with CW54 strains were significantly increased by 86.4% and 51.4% as compared to those of the control at the time of soybean podding in a field condition, respectively.These results suggested that inoculation Rhizobium was beneficial for soybean nutrient uptake,growth and yield under insoluble phosphate soil conditions.     

酸性条件下接种根瘤菌对热研2号柱花草产量及含氮量的影响

通过水培试验,研究不同酸I生条件下接种5株根瘤菌对热研2号柱花草产量和含氮量的影响,结果表明,在3个酸性条件下接种5株根瘤菌都能提高柱花草植株的干质量和含氮量;除菌株PN13-3在pH3．5时的产量最高外,其他菌株都是在pH4．5时产量及含氮量最高,与不接菌（CK）一致;菌株PN13-3适合用于较酸的环境中,菌株BS1—1,RJS9—2次之;菌株在酸性逆境条件下对柱花草的促生能力较强,植株干质量和含氮量的增加倍数随pH的降低而升高。     

Long-term effects of alternative and conventional fertilization I: Effects on arbuscular mycorrhizal fungi community composition

The influence of long-term fertilization on arbuscular mycorrhizal fungi community composition was investigated. Soil samples were taken from a long-term field experiment which was conducted for 5 years to explore the effect of three treatments: control (non-fertilization), conventional (mineral fertilizers—NPK), and alternative (organic fertilizers—farmyard manure). The highest values of AMF community composition were found in the alternative fertilization system after the thirty year of its utilization. After the thirty year the conventional fertilization system showed lower AMF diversity compared to alternative fertilization system. In conclusion the alternative fertilization system enhanced mycorrhizal effectiveness that contributes to increase wheat growth after a long-term experiment. Our findings also suggest that inputs of organic matter source can change positively the AMF community composition, and these results highlight the importance of considering the long-term effect of mineral and organic fertilizers on the AMF community diversity. Thus, the long-term utilization of an alternative fertilization system with continuous input of organic matter may exploit positive situations of jointly beneficial biotic and abiotic conditions.     

Long-term effects of alternative and conventional fertilization II: Effects on <Emphasis Type="Italic">Triticum aestivum</Emphasis> L. development and soil properties from a Brazilian ferralsols

The influence of long-term fertilization on plant development and soil properties was investigated. Soil samples were taken from a long-term field experiment which was conducted for 5 years to explore the effect of three treatments: control (non-fertilization), conventional (mineral fertilizers—NPK), and alternative (organic fertilizers—farmyard manure). The highest values of plant yield and soil properties were found in the alternative fertilization system after the thirty year of its utilization. Conventional fertilization showed positive effects until the second year of its utilization where enhanced soil fertility (total nitrogen and available phosphorous content) and plant development (plant yield, plant dry biomass, plant phosphorous concentration, and plant nitrogen concentration). After the thirty year the conventional fertilization system showed lower values for these studied variables compared to alternative fertilization system. Our findings suggest that inputs of organic matter source can change positively the wheat growth and soil fertility, and these results highlight the importance of considering the long-term effect of mineral and organic fertilizers on these variables.     

施氮量对间作小麦蚕豆根系分泌槲皮素和橙皮素的影响

【目的】系统探讨间作条件下,不同施氮水平不同生育期小麦和蚕豆根系分泌槲皮素和橙皮素的动态变化及累积特征,为进一步探明间作增产控病机制提供依据。【方法】通过盆栽试验,采用小麦与蚕豆根系尼龙分隔(MB)和塑料分隔(PB)两种间作种植模式,测定间作小麦蚕豆不同氮水平(低氮1/2N:常规施氮量的一半;常规施氮N;高氮3/2N:常规施氮量的1.5倍)条件下,不同生育期根系分泌槲皮素和橙皮素数量。【结果】施氮水平和间作体系根系不同分隔方式影响作物生物量和根冠比。随着施氮量增加,小麦和蚕豆生物量增加45%—62.5%和3.2%—18.9%,根冠比降低33.8%—47.3%和11.8%—26.9%;与塑料分隔相比,相同施氮水平条件下,作物生长60 d时,尼龙分隔小麦和蚕豆生物量分别提高4.2%—25%、19%—38.6%,随生长天数增加差异逐渐不显著。间作根系不同分隔方式和施氮量均能影响小麦蚕豆根系槲皮素和橙皮素的分泌量。随施氮量增加,小麦蚕豆槲皮素和橙皮素分泌量减少,与低氮条件相比,常规施氮和高氮条件下,小麦槲皮素分泌量减少了23.4%和62.3%,橙皮素分泌量减少了32.2%和64.5%;蚕豆槲皮素分泌量减少了35.4%和44.1%,橙皮素减少了11.9%和23.9%。相同氮水平条件下,尼龙分隔小麦蚕豆槲皮素和橙皮素分泌量高于塑料分隔,低氮和常规施氮条件下,尼龙分隔小麦槲皮素的分泌量分别高于塑料分隔15.3%和27.1%,橙皮素的分泌量分别高于塑料分隔21%和13.7%;蚕豆根系尼龙分隔槲皮素分泌量高于塑料分隔34.6%和56.6%,橙皮素高于塑料分隔16.9%和5.1%;高氮条件下两种根系分隔方式之间差异不显著。【结论】间作根系不同分隔方式影响小麦和蚕豆根系槲皮素和橙皮素的分泌,但这种影响受施氮水平的调控,低氮和常规施氮条件下,尼龙分隔小麦和蚕豆根系槲皮素和橙皮素分泌量高于塑料分隔,高氮条件下差异不显著。     

滴灌施肥对设施番茄水氮利用效率及土壤硝态氮残留的影响

为了解滴灌施肥是否能够提高水氮利用效率、降低环境污染风险,总结山东寿光设施番茄长期定位试验9季的试验结果,系统分析传统漫灌施肥和滴灌施肥对番茄产量、水氮利用效率、土壤硝态氮残留和经济效益的影响。与传统漫灌施肥相比,滴灌施肥每季氮肥和水分投入量分别降低78%和46%,氮肥偏生产力和灌溉水利用效率则分别提高5和2倍,番茄产量和经济效益分别提高6%和22%,且产量年际变异显著降低。传统漫灌施肥0~90cm土层硝态氮残留量平均高达819kg/hm2,滴灌施肥降低50%的土壤硝态氮残留。与传统漫灌施肥相比,滴灌施肥栽培体系是一个低投入、低环境代价和高效稳定的生产体系。     

固氮菌的筛选及其对菜场垃圾堆肥化的影响

分别以可溶性淀粉、鼠李糖、蔗糖为唯一碳源的无氮培养基,从校园土壤中分离到褐球固氮菌(Azotobacter chroococcum)、维涅兰得固氮菌(A.vinelandii)和拜氏固氮菌(A.beijerinckii)三种菌种各2株菌株。将3种菌种单独及混合分别投加到菜场垃圾堆肥装置中。结果表明,接种混合固氮菌的菜场垃圾废物堆肥的全氮、铵态氮、硝态氮的含量最高,堆肥化所用的时间最短。接种一种固氮菌(褐球固氮菌、拜氏固氮菌或维涅兰得固氮菌)的也有所提高。     

海洋石油污染物微生物降解的研究

[目的]探讨微生物降解海洋石油污染物的最佳条件。[方法]选择大庆原油为降解底物,以分离的优势石油降解菌为研究对象,首先通过单因素试验研究了初始盐度、pH和营养盐等因素对菌株SY1和SY2降解石油的影响,然后通过正交试验确定最佳降解条件。[结果]单因素试验表明,初始pH和氮源浓度对菌株降解石油的影响较显著,同时添加氮、磷营养盐能取得更好的降解效果。正交试验表明,菌株SY1在最优组合下石油降解率达59.0%,主要影响因素是磷浓度;菌株SY2在最优组合下石油降解率为57.4%,主要影响因素是盐度和pH。[结论]该研究为菌株对石油降解性能的研究提供了理论参考。