岷江干旱河谷豆科植物多样性及其空间格局     

李芳兰  包维楷  朱林海 《山地学报》2010,28(1)

为研究岷江干旱河谷的豆科植物物种多样性及其在纬度和海拔梯度上的分布格局,在从四川汶川到松潘的干旱河谷两岸选择了7个地点,通过204个样方 (2 m×2 m) 调查,分析了不同纬度和海拔豆科物种组成、高度、盖度与根系结瘤的空间分布特点.结果表明:(1) 在所有样方中共出现乡土豆科植物16属,38种,其中灌木7属19种;草本植物7属17种,1或2 a生草本 6种,多年生草本11种.仅刺槐 (Robinia pseudoacacia L.) 和葫芦巴 (Trigonellae foenum-graecum L.) 为栽培物种.灌木在该地区豆科植物中占较大优势,50%以上灌木的频度与盖度均＞10%,尤其白刺花 (Sophora davidii)、小马鞍羊蹄甲 (Bauhinia brachycarpa var.microphylla)、岷谷木蓝 (Indigofera lenticellata) 等灌木频度＞20%,而所有草本植物的频率及盖度都＜10%. (2) 豆科植物丰富度及生长具有较为明显的空间差异,干旱河谷核心地区的干热、贫瘠环境中,总物种丰富度较高,但是其盖度与高度较小.随着纬度升高,灌木丰富度和频度均减少,草本丰富度与和频度增加.随着海拔上升,灌木丰富度与总物种丰富度都减小,草本植物丰富度变化不明显;植物平均高度与盖度高度也无明显的垂直变化规律.(3) 植物根系结瘤能力很低,66%物种未结瘤,并且幼苗结瘤能力显著大于成株.这一结果可为豆科植物资源的保护和开发利用提供科学依据.  相似文献   

Effect of rhizobia inoculation on the seed (herbage) production of mungbean (Phaseolus aureusRoxb.) grown at Uzbekistan     

N.A. Provorov  U.B. Saimnazarov  I.U. Bahromov  D.Z. Pulatova  A.P. Kozhemyakov  G.A. Kurbanov 《Journal of Arid Environments》1998,39(4):569-575

In field trials conducted at Uzbekistan, inoculation of mungbean (Phaseolus aureusRoxb.) with commercial strain CIAM1901 ofBradyrhizobiumsp. (Phaseolus) increased (on average for two cultivars) the herbage mass by 46·6±6·0%, seed mass by 39·2 ± 3·6%, mass of 1000 seeds by 16·0 ± 0·8%, nitrogen content in seeds by 58·3 ± 8·9%, starch content in seeds by 30·0 ± 5·5% and number of nodules by 254%. Inoculation with this strain produced the same herbage (seed) mass as NH₄NO₃application (120 kg ha⁻¹of N), while the combined treatment of rhizobia and 60 kg ha⁻¹of N produced significantly higher yields than rhizobia inoculation alone or application of 120 kg ha⁻¹of N. The rhizobia strain M11 was isolated from Uzbekistan soils and significantly exceeded the commercial strain CIAM1901 in its influence on herbage mass by 3·9–10·6%. Two-factor analysis of variance demonstrated that the herbage mass and number of nodules are controlled mainly by the rhizobia strain genotypes, while seed yield, number of pods, mass of 1000 seeds and N and starch content in seeds are influenced by the plant cultivar genotypes.  相似文献   

Effects of preservatives on stable isotope analyses of four marine species     

Sirka Carabel  Patricia Verísimo  Juan Freire 《Estuarine, Coastal and Shelf Science》2009

The aim of the present study is to quantify the effect of formalin–ethanol preservation on the carbon and nitrogen stable isotope signatures of four taxonomical groups of marine species (Himanthalia elongata, Anemonia sulcata, Mytilus galloprovincialis and Patella vulgata). To examine temporal changes in the effects of preservation and to determine if preservation induced predictable shifts in δ¹³C and δ¹⁵N signatures, repeated analyses were carried out after 6, 12 and 24 months of preservation. Data from our study showed highly variable effects of the formalin–ethanol preservation on carbon and nitrogen isotope signatures between species. The use of a general correction factor was not possible, or else it should be species-specific. Differences in nitrogen isotopic values between preserved and unpreserved samples were minor compared to the assumed enrichment between trophic levels. The combined use of data from preserved and unpreserved samples could lead to biases in the estimation of the trophic level of organisms. Changes that preservatives caused in carbon values were variable between species and not always small enough to be ignored. So the use of data from preserved samples could change the interpretation of the mixing models used to determine the importance of multiple sources of carbon. In order to elucidate the effects that preservatives have in other species, further studies will be necessary.  相似文献   

土壤固钾与释钾机制研究进展   总被引：39，自引：0，他引：39  

梁成华  魏丽萍  罗磊 《地球科学进展》2002,17(5):679-684

根据钾素在土壤中对作物的有效性，可将其分为速效钾、缓效钾和无效钾。各种形态钾素之间存在着渐变性，并处于一种动态平衡，其中，土壤钾素固定与释放对这一平衡产生重要影响，进而影响钾素的有效性。富含 2∶ 1型粘土矿物的土壤，不仅有丰富的缓效钾储量和较强的供钾能力，而且固钾能力也较强。在淋溶性较强的砂质土壤上，固钾作用可使钾素免受淋失，有利于保存肥力和提高肥效。但是，对于多数土壤来说，将使施入土壤的大部分钾素转化为非交换性钾，其中，只有小部分可被当季作物利用。在集约农业条件下，土壤的固定已成为提高钾素利用效率的主要障碍因素。系统阐述了钾素释放与固定的概念与过程，综述了影响钾素固定与释放的主要因素；系统分析了粘土矿物类型及其结构、土壤铵态氮肥和磷肥水平、土壤水分状况、有机物和羟基铝影响钾素固定、释放过程的作用机理；并指出了土壤钾素固定和释放研究领域的发展现状和重要动向。  相似文献   

Effects of the invasive plant Lupinus polyphyllus on vertical accretion of fine sediment and nutrient availability in bars of the gravel-bed Paloma river     

Claudio I. Meier  Brian L. Reid  Orlyn Sandoval 《Limnologica》2013,43(5):381-387

Floodplain vegetation is fundamental in fluvial systems, controlling river corridor geomorphology and ecology through a series of hydraulic, sedimentological, and biological processes. Changes caused by introduced plant species can thus result in shifts in river regime, succession trajectories and nutrient availability, affecting native biodiversity. The exotic bigleaf or marsh lupine Lupinus polyphyllus, introduced in Patagonia in the last decades, is aggressively invading fluvial corridors. It fills unoccupied ecological niches in southern Chilean rivers, due to its capacity for nitrogen fixation, its perennial habit, and high shoot density and leaf surface area.We investigated the effects of L. polyphyllus on vertical accretion of fine sediment, and soil carbon and nitrogen content, on gravel bars of the Paloma river, Chilean Patagonia, where lupine is believed to have been introduced in 1994. We sampled plot pairs with and without lupine, with each pair located at the same elevation above river stage, and plots distributed over the reach scale. We measured the thickness of the fine soil horizon, grain size distribution, and soil carbon and nitrogen content. We also compared aerial photographs to evaluate changes in spatial coverage of lupine along the study reach.Presence of lupine was strongly correlated with a thicker layer of finer sediment, in turn characterized by higher organic carbon, carbon to nitrogen ratio, and inorganic carbon content. Contrary to our expectations, we did not find any significant differences in total nitrogen. Aerial photographs did not reveal important differences in coverage between 2007 and 2010, but plant density appears to have increased between the two dates, and invaded gravel bars also appear to be more stable. Lupine dominance of otherwise sparsely vegetated gravel bars in Patagonian rivers appears to have greatest consequences on bar physical structure (increased rates of accretion of fines) and secondary repercussions on soil quality (increase in recalcitrant organic matter), with potential transient effects on nutrient availability (possible increased soil metabolism, followed by carbon mineralization and loss of lupine nitrogen subsidy).  相似文献   

不同紫外波段对中肋骨条藻光合生理特性的影响     

朱镕军  高嘉钰  吴亚平  徐军田 《海洋科学》2020,44(11):45-51

人类活动导致臭氧层变薄和混合层变浅，迫使混合层的浮游植物暴露在更高的紫外辐射下。实验以中肋骨条藻（Skeletonema costatum）为研究对象，在自然光照条件下，通过在暗盒上方覆盖不同的截止型滤光板，获得不同波段紫外辐射，探讨不同紫外波段对其生理特性的影响。本实验通过在室外培养，模拟赤潮爆发状态，对中肋骨条藻进行7种不同紫外波段的处理（分别使用280、300、320、340、360、380、400 nm截止型滤光板）。实验结果表明：紫外辐射会显著抑制中肋骨条藻的光合固碳速率，随着紫外波段逐步被滤除，光合固碳速率越来越高；>280 nm和>300 nm波段下的比生长率显著低于>400 nm波段处理；280 nm~300 nm波段紫外对叶绿素a有显著的漂白效应，同时也会显著减少类胡萝卜素的含量；这表明紫外辐射对中肋骨条藻的抑制效应主要是紫外辐射B导致的，而紫外辐射A的作用不显著。在估测浮游植物海洋初级生产力的过程中，紫外辐射的作用往往被忽视。  相似文献   

Micronutrient effects on cyanobacterial growth and physiology     

John G. Rueter  Richard R. Petersen 《新西兰海洋与淡水研究杂志》2013,47(3):435-445

Trace metals play crucial roles in the carbon and nitrogen metabolism of cyanobacteria. Physiological responses to metal limitation and toxicity in culture have shown that iron is important for photosynthesis and energy distribution in the cell while both iron and molybdenum are biochemically involved in nitrate reduction and nitrogen fixation. Nitrogen fixation is also relatively sensitive to copper toxicity. Consequently, factors that affect the supply rate, chemical speciation, or the recycling of trace metals can alter patterns of primary productivity and nitrogen metabolism. Overall, three trace metal dependent processes may contribute towards dominance: efficient use of limiting light, nitrogen fixation, and production of extracellular iron binding compounds.  相似文献   

Multi-scale study of permeability evolution of a bentonite clay owing to pollutant transport: Part I. Model derivation     

F. Bouchelaghem  N. Jozja 《Engineering Geology》2009,108(1-2):119-132

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A biomarker of Diazotrophic Cyanobacteria: Heterocyst Glycolipids and Their Research Progress     

Manyu Kang  Guodong Jia 《地球科学进展》2019,34(9):901-911

Heterocystous cyanobacteria are important diazotrophs commonly found in freshwater and ocean. They can produce special glycolipids known as Heterocyst Glycolipids (HGs) in their inner membrane layer. HGs are typically long-chain diols, triols, or hydroxyketones connected with a sugar moiety. HGs are unique biomarkers of heterocystous cyanobactria, which are relative stable and can be detected in lakes, marine systems, microbial mats and sediments. The study of HGs in biogeochemistry has not been carried out until recent years. HGs are proved to have great potential in indicating heterocystous cyanbacteria community and environment conditions. In this paper, the mechanism of cyanobacterial heterocyst differentiation and structure of HGs were introduced. In particular, emphasis was put on the application of HGs to infer environmental temperature, heterocystous cyanobacteria community, terrestrial organic input and nitrogen fixationin. The prospect of future study was also proposed.  相似文献   

塔里木沙漠公路植物固沙灌溉方式比较研究   总被引：7，自引：2，他引：7  

何兴东  高玉葆  段争虎  赵爱国  陈珩 《地理科学》2002,22(2):213-218

在塔里木沙漠公路沿线两侧建立植物固沙体系时首先应确定适宜的灌溉方式。从1998年开始，我们根据不同灌溉方式本身的优缺点与前期试验结果，结合立地条件，在塔里木沙漠公路L292处选择沟灌、畦灌与滴灌进行植物固沙灌溉方式比较试验，对不同灌溉方式植物生长状况、沙层直渍度变化、制度及成本投入比较分析后认为，滴灌不受起伏沙丘地形限制，水利利用效率高，能够保证植物正常生长，且费用最低，因而是塔里木沙漠公路植物固沙的首选灌溉方式。  相似文献