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[目的] 探讨热带云雾林土壤酶活性的季节动态规律及根际效应,为从土壤酶学角度出发研究热带云雾林水土保持生态功能提升提供科学依据。[方法] 采用抖落法采集3种优势树种岭南青冈、罗浮锥、细枝柃根际和非根际土壤样品,对土壤酶活性季节动态变化进行研究,并分析不同树种根际土壤酶的根际效应及其与土壤养分的关系。[结果] ①热带云雾林不同树种根际与非根际土壤酶活性季节动态变化明显,呈单峰型变化趋势,峰值出现在雨季8月;岭南青冈、罗浮锥土壤酶活性差异不显著,但显著大于细枝柃。②根际土壤酶活性均高于非根际土壤,表现为正根际效应。土壤酶根际效应表现为:酸性磷酸酶 > 脲酶 > 过氧化氢酶 > 蔗糖酶;不同树种酸性磷酸酶、脲酶、蔗糖酶根际效应差异不显著,而过氧化氢酶根际效应表现为岭南青冈、罗浮锥显著大于细枝柃。③土壤酶活性与土壤N,P,K养分含量呈显著正相关,与土壤含水量、pH值相关性不显著。[结论] 热带云雾林主要优势树种土壤酶活性呈现明显的季节动态变化,根际效应显著,N,P,K养分限制可能是土壤酶活性及其季节变化的主导控制因子。  相似文献   
3.
[Objective] The aim of this study is to understand the dynamics of cotton rhizosphere bacterial community structure in cotton continuous cropping field soil. [Method] 16S rDNA genes were sequenced by high-throughput sequencing technology to determine the community structure of cotton rhizosphere bacteria in different developmental stages using an upland cotton cultivar (Gossypium hirsutum cv. TM-1). [Result] Four dominant phyla were found in the cotton rhizosphere bacterial community including Proteobacteria, Acidobacteria, Planctomycetes, and Bacteroidetes. The four dominant phyla and Firmicutes were largely influenced by cotton root. The relative abundances of Acidobacteria, Planctomycetes, Bacteroidetes were promoted, and Proteobacteria and Firmicutes were inhibited, by cotton root. There were significant differences in community structure, but not species richness or α-diversity among different developmental stages of the cotton rhizosphere bacterial community; the differences between the flowering stage and the budding stage were greater than the differences between the budding stage and the seedling stage. The diversity of the rhizosphere bacterial community in cotton continuous cropping field soil was significantly higher than that of the bulk soil; the β-diversity values of both the rhizosphere and bulk soil bacterial communities were highest in the flowering stage. [Conclusion] The structure and dynamics of the cotton rhizosphere bacterial community in cotton continuous cropping field soil was defined by high-throughput sequencing. The effect of cotton on the rhizosphere bacterial community structure was most significant in the flowering stage.  相似文献   
4.
绿僵菌防治草原蝗虫效果显著,其在草原田间的存活能力影响其持续控害效果。除了侵染昆虫,绿僵菌还具有在植物根际宿存和根内生的生活方式,但相关宿存规律和内生性的研究报道很少。本文研究了绿僵菌在内蒙古草原两种优势种植物羊草和克氏针茅根际的种群数量变化并对其在这两种草的根内宿存进行了鉴定。结果表明,在干旱的内蒙古草原,绿僵菌施用后种群数量在30 d内快速下降,但能够以低密度在羊草、克氏针茅根际土壤中至少延续宿存75 d,羊草根际环境比较利于绿僵菌生存。对菌株egfp基因标记的特异PCR检测证明了绿僵菌在羊草和克氏针茅根内宿存。试验数据为指导植保生物防治中充分利用绿僵菌的昆虫病原性和植物内生特性提供理论基础,也将成为绿僵菌物种生活方式多样性、与植物互作及共进化研究的重要基础。  相似文献   
5.
高粱绿肥种植密度对设施黄瓜根系生长相关因子的影响   总被引:1,自引:0,他引:1  
以设施黄瓜为研究对象,在黄瓜定植前40 d分别播撒240、120、60 kg/hm~2不同密度高粱种子,并于黄瓜定植前将高粱植株作为绿肥翻入土壤,研究其对黄瓜结果期生长指标、根际土壤养分含量以及细菌群落结构变化的影响,探讨其影响黄瓜生长指标、根际养分含量和菌群结构变化的内在机制。试验结果表明:240 kg/hm~2种植密度的高梁绿肥可显著提高黄瓜根际土壤有机质质量比31.66%、碱解氮质量比8.75%、速效磷质量比13.89%、速效钾质量比16.86%、脲酶活性6.85%,显著提高结果期黄瓜茎粗12.83%、根系数15.81%、根总体积24.11%、叶片总面积11.43%、单株结瓜数10.97%、总产量9.81%;240 kg/hm~2种植密度的高粱绿肥可明显提高黄瓜根际土壤中变形菌门、放线菌门、厚壁菌门比例而降低酸杆菌门、绿弯菌门、拟杆菌门比例,明显提高鞘脂单胞菌科、黄色单胞菌科、红螺菌科、中华杆菌科、生丝微菌科比例而降低Gp6科、Gp16科、Gp4科比例。该处理主要通过降低根际土壤绿弯菌门和提高鞘脂单胞菌科、中华杆菌科比例而提高脲酶活性,通过提高厚壁菌门、黄色单胞菌科、红螺菌科和降低根际土壤酸杆菌门比例而促进碱解氮质量比、速效磷质量比、茎粗、叶片总面积、根系数、根总体积的提高,最终促进黄瓜生长并提高产量。  相似文献   
6.
以不同栽培代数的木麻黄(第1代FCP、第2代SCP、第3代TCP)根际土壤为试验材料,运用BIOLOG微平板和磷脂脂肪酸(PLFA)技术分析根际土壤微生物群落结构和功能多样性对多代连栽响应。结果表明,不同代数的土壤微生物对各类碳源的利用程度存在显著差异,连栽后木麻黄根际土壤微生物对碳源利用率显著下降。在6类碳源中,除胺类外,其他5种碳源均呈现FCP>SCP>TCP。PLFA分析共检测到11种PLFA生物标记,FCP土壤微生物PLFA生物标记总量明显高于SCP和TCP,3个代数土壤中含量最高的PLFA生物标记是i16:0、a15:0和18:1ω9c。土壤中特征微生物含量差异明显,细菌分布量最大,其次是真菌和放线菌。随栽植代数增加,细菌含量减少,真菌含量增加。土壤微生物群落多样性指数均呈现FCP>TCP>SCP,与土壤理化性质变化密切相关。可见木麻黄连栽显著影响其根际土壤微生物群落结构与功能,因此根际土壤微生态失衡可能是导致木麻黄连栽障碍的重要因素。  相似文献   
7.
马源  张德罡 《草业学报》2020,29(11):172-182
了解根际土壤养分碳、氮和磷的转化和循环利用是解决草地农业生态系统可持续利用性和提高草地生产力的根本问题。草地根际过程能够反映土壤碳、氮和磷等养分的周转速率,影响植物、土壤微生物对养分的竞争和捕获,维持根际微环境中各组分的养分平衡,同时与作物相比,草地土壤中养分元素碳、氮和磷的耦合性更强。因此,根际微生态系统结构与功能在维持养分转化和循环等方面具有重要作用。大量文献报道,调控根际微环境改变的关键因素是植物与土壤进行物质交换和信息传递的关键物质-根际分泌物,同时根际分泌物也是介导根际微生物和根际酶活性的关键物质。当草地环境发生改变时,该区域的根际分泌物、根际酶活性和根际土壤的微生物的组成和多样性也将发生根本性改变,从而导致该区域土壤养分的供应量和有效性发生改变,最终影响草地生产力和养分的有效利用效率。因此,深入探究草地根际过程对养分循环的调控机理,对于揭示草地植物与微生物间养分物质的分配利用和养分收益方面具有重要指导意义。综述了根际分泌物、根际酶和根际微生物参与养分循环的机制和互作机理,总结草地根际过程参与养分循环的机制,并对草学领域未来在根际微域的研究进行了一定的展望。  相似文献   
8.
Modern breeding primarily targets crop yield traits and is likely to influence root-associated microbiomes, which play significant roles in plant growth and health. The relative importance of soil and cultivar factors in shaping root-associated microbiomes of modern maize (Zea mays L.) remains uncertain. We conducted a pot experiment in a controlled environment using three soils (Mollisol, Inceptisol, and Ultisol) and four contrasting cultivars, Denghai 605, Nonghua 816, Qiaoyu 8, and Zhengdan 958, which are widely planted in China. We used 16S rRNA gene amplicon sequencing to characterize the bacterial communities in the bulk soil, rhizosphere, and endosphere. Our results showed that the four cultivars had different shoot biomass and root exudate total organic carbon and organic acid contents. The microbiomes in the bulk soil, rhizosphere, and endosphere were different. We observed apparent community divergence between soils rather than cultivars, within which edaphic factors substantially contributed to microbiome variation. Moreover, permutational multivariate analysis of variance corroborated significant contributions of soil type but not cultivar on the root-associated microbiome structure. Differential abundance analysis confirmed that each soil presented a distinct root microbiome, while network analysis indicated different co-occurrence patterns of the root microbiome among the three soils. The core root microbiome members are implicated in plant growth promotion and nutrient acquisition in the roots. In conclusion, root-associated microbiomes of modern maize are much more controlled by soil characteristics than by cultivar root exudation. Our study is anticipated to help improve breeding strategies through integrative interactions of soils, cultivars, and their associated microbiomes.  相似文献   
9.
Background : Manganese deficiency often becomes a yield limiting factor, particularly on calcareous soils, even though the total soil manganese content is usually sufficient. Although it is known that acidifying N fertilizers can improve Mn availability, the reason of this effect is still unknown. Aim : Our aim was to investigate the effect of stabilized ammonium fertilizers as a tool to distinguish between physiological‐ and nitrification‐induced acidification. Method : Two pot experiments with Triticum aestivum L. and one soil incubation experiment using different nitrogen forms (CN = calcium nitrate, AN = ammonium nitrate, AS = ammonium sulfate, ATS = ammonium thiosulfate) with and without addition of nitrification inhibitors (DCD, Nitrapyrin, Piadin, DMPP) were conducted to examine the effect on Mn availability in the soil and Mn uptake by the plants at different development stages (EC 31 und 39). Results : With increasing fertilizer NH 4 + content a higher Mn concentration was detected: CN: 32 µg Mn g?1 DM, AN: 39 µg Mn g?1 DW, AS: 55 µg Mn g?1 DM, ATS: 109 µg Mn g?1 DM. The addition of a nitrification inhibitor resulted in a significantly lower rhizosphere pH compared to the non‐stabilized fertilizer. Surprisingly, the use of different nitrification inhibitors led to unchanged (CN, AN) or lower Mn concentrations of wheat. Especially in the NH 4 + treatments (AS and ATS), this negative effect was very evident (AS+DCD: 42 µg Mn g?1 DM; ATS+DCD: 55 µg Mn g?1 DM). Conclusions : Mn availability was enhanced by ongoing nitrification process rather than physiological acidification. Compared to other N forms, ammonium thiosulfate led to the highest Mn availability in bulk soil.  相似文献   
10.
转基因作物对土壤生态系统的影响日益引起人们的广泛关注。采用Biolog ECO微平板对转基因抗虫玉米IE09S034及其对应的受体玉米根际微生物群落碳代谢功能进行了比较研究。结果表明,转基因抗虫玉米IE09S034对根际微生物碳代谢功能无显著性影响,且发现年份和生育期是引起根际微生物碳代谢情况变化的主要因素。本文为转基因抗虫玉米IE09S034的环境安全性评估提供了新的依据。  相似文献   
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