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1.
以延河流域中阿尔泰狗娃花、茭蒿、铁杆蒿、白羊草、大针茅、长芒草6种常见草本植物为研究对象,测定植物的10种易于测量且能反映生存策略的功能性状,包括比叶面积(SLA)、叶组织密度(LTD)、比根长(SRL)、根组织密度(RTD)、叶氮含量(LNC)、叶磷含量(LPC)、叶氮磷比(LNP)、根氮含量(RNC)、根磷含量(RPC)、根氮磷比(RNP),结合植物遗传背景和环境数据,研究植物功能性状对环境变化的响应,分析了植物功能性状变异的来源。结果表明:(1)不同气候条件下,除了叶组织密度LTD这一植物性状差异不显著外,其他功能性状均表现出显著差异;菊科的SLA,LNC,LPC,RNC,RNP显著高于禾本科,SRL显著低于禾本科。(2)植物物种和气候变化是性状变异主要来源,对研究的8个性状变异来源的影响程度进行排名,物种年均降雨量年均蒸发量年均温度坡度坡位海拔坡向。(3)不同物种根据自身不同遗传背景和环境耐受性,在环境变化时调节自身性状的表达,以产生相应的生存策略。  相似文献   

2.
[目的]分析刺槐在黄土丘陵区不同立地条件下的适应机制及适应成本,为该区的植被恢复提供理论依据。[方法]采用野外调查方法,对黄土高原丘陵区不同坡向和坡位的刺槐群落功能性状、生长状况差异进行研究,分析影响刺槐生长的主要因素。[结果]①阳坡刺槐的叶氮含量、叶磷含量、叶有机碳含量、根磷含量、根有机碳含量、根组织密度均大于阴坡;根氮含量、叶厚度、叶组织密度、比叶面积、比根长均小于阴坡。随坡位上升,叶氮含量、叶磷含量、叶有机碳含量、根磷含量、根氮含量、比叶面积、叶厚度均呈减小趋势;根有机碳含量和叶组织密度呈增大趋势。②刺槐功能性状与环境因子间响应关系显著;性状间的协变和权衡关系在同一器官和不同器官间均存在。③刺槐的株高、胸径、地径、冠幅均表现为阳坡大于阴坡,且随坡位升高而显著减小;其生长状况与功能性状间关系显著。[结论]刺槐在阳坡和下坡位适应成本较低,能够发挥相对大的生态效益。  相似文献   

3.
黄土丘陵区植物功能性状沿气候梯度的变化规律   总被引:2,自引:0,他引:2  
施宇  温仲明  龚时慧  宋光  郑颖  丁曼 《水土保持研究》2012,19(1):107-111,116
选取黄土丘陵区延河流域147个物种,对10个与植物形态、生理相关的叶片和细根功能性状(叶大小、叶长宽比、叶厚度、叶干重、比叶面积、叶组织密度、叶氮含量、细根比根长、细根组织密度和细根氮含量)进行了测定,并对功能性状与气候因子的关系进行了分析。结果表明:(1)水热条件是影响研究区植物功能性状的重要因子,其中降雨为主导因子。物种水平上,植物功能性状随着环境的变化而变化,如叶氮含量随着温度指标(最冷月均温、生长季均温、年均温、最热月均温、温度季节变化的增加而增加;(2)不同生长型功能性状在环境梯度下存在差异,表现为草本植物相对木本植物有更小的叶组织密度以及更大的叶面积、比叶面积、叶片氮含量、根氮含量和比根长,表明不同生活型植物对环境的适应能力明显不同;(3)不同类群植物对环境条件变化的响应不同,表现为适应方式的分异和趋同。该结果为探究黄土高原植物对环境的适应机制提供理论依据。  相似文献   

4.
植物功能性状是表征植物与环境关系的重要媒介。不同种群间功能性状的差异直接决定其竞争优势,并决定群落的结构和功能,影响整个群落的演替与发展。以黄土丘陵区森林草原带不同立地环境下的刺槐林和乡土植物群落为研究对象,比较二者功能性状随立地环境的变化,进而阐明其对不同环境的适应策略。结果表明:(1)同一坡向,刺槐林和乡土植物群落的叶N含量、根C含量、根N含量、比叶面积、叶组织密度及比根长之间有显著性差异(p0.05),而根P含量、根组织密度只在阴坡上有显著性差异(p0.05)。除叶组织密度、根组织密度、根P含量外,刺槐其他各功能性状值均高于乡土植物群落。在同一坡位,刺槐林叶C含量、叶N含量和根C含量、根N含量、比叶面积、比根长整体上显著高于乡土植物群落(p0.05);(2)刺槐林的土壤C含量、土壤P含量在阴阳坡上均低于乡土植物群落,阳坡土壤N含量高于乡土植物群落,阴坡上则相反;在不同坡位上,两者的土壤C含量有显著性差异(p0.05);(3)刺槐林和乡土植物群落5m的土壤含水量变化基本一致。刺槐林下土壤含水量低于乡土植物群落。在干旱贫瘠的环境中,刺槐林具有较高的叶养分含量、根养分含量、比叶面积和比根长,具备较强的水分和养分竞争能力;而乡土植物群落具有较小的比叶面积、较大的叶组织密度和根组织密度,虽然可以较好地维持体内水分和养分的平衡,形成对环境的有效适应,但相比刺槐水分和养分竞争能力较弱。因此,在黄土丘陵区植物恢复重建中,要充分考虑物种对环境的适应性及其对生长的影响,要维持物种适应环境与健康生长间的平衡。  相似文献   

5.
黄河三角洲盐碱地人工刺槐混交林细根分布研究   总被引:1,自引:0,他引:1  
为研究黄河三角洲盐碱地人工刺槐混交林及纯林细根空间分布格局,选取绒毛白蜡刺槐混交林、臭椿刺槐混交林、刺槐纯林,采用土柱法取样,从细根生物量密度、表面积密度、体积密度、根长密度等方面研究盐碱地中不同林分中树木细根的垂直分布情况,从细根生物量分析不同林木细根垂直分布情况,研究不同人工林细根分布差异及土壤影响因子。结果表明:绒毛白蜡刺槐混交林在细根的生物量、表面积、体积、根长等方面都显著高于臭椿刺槐混交林和刺槐纯林;绒毛白蜡刺槐混交林95.77%细根生物量分布在0~60 cm土层,臭椿刺槐混交林85.37%细根生物量分布在0~40 cm土层,而刺槐纯林的细根在土壤中分布则比较均匀,0~40 cm土层细根占生物量总量的66.38%。绒毛白蜡细根生物量最高,显著高于其他林木。绒毛白蜡刺槐混交林细根表面积密度、体积密度、根长密度显著高于刺槐纯林;臭椿刺槐混交林高于刺槐纯林,差异不显著。绒毛白蜡刺槐混交林、臭椿刺槐混交林细根总根尖数分别是刺槐纯林的2.34倍、1.23倍,总分叉数分别为刺槐纯林的6.15倍、1.66倍。绒毛白蜡刺槐混交林、臭椿刺槐混交林、刺槐纯林树木细根生物量与土壤有效磷、速效钾含量呈显著正相关关系;绒毛白蜡刺槐混交林细根生物量碱解氮、有机质含量呈极显著正相关关系。适当的混交模式在一定程度上提高了人工林细根生物量,增强植物吸收土壤营养物质的能力,混交使人工林在盐碱立地条件下适应能力提高。  相似文献   

6.
菘蓝农艺性状与药材产量的相关和通径分析   总被引:4,自引:0,他引:4  
为探究菘蓝主要农艺性状的变异特征,明确药材产量形成的决定因子,合理评价与利用现有种质资源及选育品种提供参考依据,本研究以18份国内菘蓝主栽区的种质资源为试验材料,通过测定11个农艺性状,采用相关分析、回归分析、通径分析等方法,探讨菘蓝主要农艺性状之间的关系。结果表明,菘蓝主要农艺性状变异丰富,变异系数(CV)达9.83%~69.22%,根鲜重、叶鲜重和叶面积的CV均大于60%,大青叶和板蓝根产量的CV大于50%,根直径、叶干物质含量、根长、根干物质含量CV较小。大青叶产量与根干物质含量呈显著负相关,与叶片干物质含量呈负相关,与其他农艺性状都呈极显著正相关;板蓝根产量与叶、根干物质含量均呈负相关,与其他农艺形状均呈极显著正相关。采用逐步回归分析,分别建立大青叶产量和板蓝根产量与农艺性状之间的回归模型,经统计学检验,两个模型均达极显著水平,其决定系数分别为0.989、0.982。通过通径分析,确定影响大青叶产量的关键农艺性状依次为叶片数(0.715)、叶鲜重(0.594)、根鲜重(0.140)和侧根数(0.131),而影响板蓝根产量的关键农艺性状为根长(0.837)和根鲜重(0.592)。菘蓝种质资源具有丰富的遗传多样性,大青叶产量形成的决定因子为叶片数、叶鲜重、根鲜重和侧根数;板蓝根产量形成的决定因子为根长和根鲜重。高产型大青叶的品种特征为叶片数多、叶和根鲜重均重、侧根数较多;高产型板蓝根的品种特征为根长和根鲜重。本研究为菘蓝种质资源鉴定及品种选育提供了理论依据。  相似文献   

7.
晋西黄土区不同植被类型土壤抗冲性及表层根系分布特征   总被引:3,自引:1,他引:2  
采用原状土冲刷水槽法,以油松林、刺槐林、山杏林、荆条地及荒草地土壤为研究对象,研究了晋西黄土残塬沟壑区蔡家川流域不同植被类型土壤抗冲性能及植物根系对土壤抗冲性的影响。结果表明:(1)在原状土冲刷试验过程中,各植被类型径流量随冲刷时间的变化趋势不明显,含沙量随时间延长先减少后趋于平稳,土壤抗冲指数呈逐渐增加的趋势。(2)各植被类型总根长密度、根表面积密度、根体积密度及根生物量密度均表现为刺槐、油松林地较大,山杏、荆条、荒草地较小且相差不大,总根系参数之间均存在正相关关系。各植被类型不同根径范围(0~0.5,0.5~1.0,1.0~2.0,2.0~5.0,5.0 mm)的根系指标中,0~0.5 mm径级的根长密度均最大,根体积密度总体表现为细根比粗根小。(3)不同植被类型植物根系均能增强土壤的抗冲性,增强效应表现为刺槐林地和油松林地较强,山杏、荆条、荒草地较弱。植物根系指标中1 mm径级的根长密度、根表面积密度、根体积密度与土壤抗冲性增强值呈显著或极显著正相关关系。其他径级根系参数与土壤抗冲性增强值相关性不显著。  相似文献   

8.
以黄土丘陵区4种典型植物种群(狼牙刺、白羊草、铁杆蒿、达乌里胡枝子)为研究对象,采用野外采样、室内模拟试验与分析相结合的方法,对0—30cm土层的各径级根系密度参数(根长密度、根体积密度、根表面积密度)与土壤理化性质、土壤分离速率间的关系进行了研究。结果表明:(1)4种植物的根系径级主要集中在0D≤1.0mm之间,86%~93%的根长和46%~61%的根表面积分布在此范围内,且根系径级越大,根系各密度参数越小;(2)4种植物各径级根密度参数对土壤理化性质(容重、有机质、团聚体)的影响各不相同;狼牙刺根系直径为0D≤1.0mm的根密度参数与土壤容重、有机质含量呈极显著相关;铁杆蒿在0D≤1.0mm径级的根密度参数与土壤容重呈极显著负相关,与土壤有机质含量呈极显著正相关,所有径级的根密度参数与土壤团聚体均呈显著正相关;白羊草在0D≤5.0mm径级区间内的根可有效改善土壤的容重,在0D≤2.0mm径级根密度参数与土壤有机质、团聚体呈显著正相关;达乌里胡枝子在3.0D≤5.0mm径级的根对土壤容重影响显著,直径D1.0mm的根对土壤团聚体有显著的影响;(3)土壤分离速率与根系各密度参数呈负相关。除达乌里胡枝子外,其他3种植物在0.0D≤1.0mm径级上根密度参数与土壤分离速率均呈极显著负相关。  相似文献   

9.
土壤水分胁迫对红砂幼苗细根形态和功能特征的影响   总被引:2,自引:1,他引:1  
通过盆栽人工模拟干旱试验,研究了土壤水分胁迫对红砂幼苗细根形态及功能的影响。结果表明:(1)随胁迫程度的加剧红砂幼苗细根直径和体积呈减小趋势,而根长、比根长、表面积、比表面积均呈增大趋势,表明在胁迫条件下,红砂幼苗细根可通过根长、比根长、表面积、比表面积的增加与直径和体积的减小来适应逆境胁迫。随根序的升高红砂幼苗细根直径呈增大趋势,而根长和比根长表现出减小趋势,比表面积呈先升高后降低的趋势。(2)随胁迫程度的加剧红砂幼苗细根全C含量呈降低趋势,而全N含量先呈明显的降低趋势,后呈升高趋势,表明在中度胁迫下红砂幼苗细根呼吸作用明显降低。随根序的升高红砂幼苗细根全C含量呈增加趋势,而全N含量呈下降趋势,表明红砂幼苗较低级根序具有较强的呼吸作用与代谢活性。(3)红砂幼苗细根根长与全C含量之间呈极显著正相关关系;直径与全C含量之间呈显著正相关关系;比根长与C含量呈显著负相关关系。  相似文献   

10.
徐莹    邓磊   《水土保持研究》2023,30(3):181-187
[目的]揭示祁连山青海云杉中龄林细根分布与土壤环境的互作关系,明晰不同混交度下土壤养分对细根发育的贡献因子,为祁连山天然林抚育经营提供理论依据。[方法]采用根钻法对混交度为0,0.2,0.4,0.6的青海云杉中龄林进行细根取样,揭示不同土层细根形态特征,剖析了与土壤理化性质的关系。[结果]细根生物量集中分布在0—20 cm土层,0—20 cm的土层细根生物量密度、根长密度、根表面积密度、比根长、比表面积显著高于20—40 cm土层(p<0.05),混交度0.4的林分各土层细根形态指标最大。4种混交度林分各土层中全氮含量、全磷含量、速效钾含量、有机质含量随土层深度的增加呈降低趋势,且各土层均以混交度0.4为最高。细根的总生物量密度、根长密度、根表面积密度、比根长、比表面积与0—40 cm土层中土壤全氮、全磷、碱解氮、速效磷、有机质、速效钾含量呈正相关,与全钾呈负相关关系。[结论]细根生物量密度变化主要受土壤全氮含量的影响,混交度0.4的青海云杉中龄林有较强的细根贡献和较好土壤肥力,更有利于群落稳定效益的发挥。  相似文献   

11.
Appropriate compost standards are being considered in Canada. Five aspects of compost safety and quality are being evaluated; probably the most controversial aspect is the standards for metals in compost. In order to assist in the development of appropriate standards, the authors began an extensive research project in October, 1993 to determine the bioavailability of metals from compost and compost-metal mixtures. Swiss chard was grown in compost-amended soils or compost in a growth room using five treatments of increasing percentages of compost in the media (0, 25 percent, 50 percent, 75 percent, 100 percent compost (v/v)). A Truro loamy sand and a race-track manure-biosolids compost (RTM-biosolids) supplemented with a high metal biosolids were used in a completely randomized design with five replicates. Dry matter yield, metal content in plant tissue, and total metal uptake were evaluated as well as the total and DTPA-extractable metal content in the compost-soil mixes. The results of this and five other experiments conducted by the authors will help determine whether the suggested limits for As, Cd, Co, Cr, Cu, Hg, Mo, Ni, Pb, Se and Zn in composts are appropriate.  相似文献   

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13.
Abstract

The seasonal patterns of foliage nutrient concentrations and contents were monitored for two growing seasons in an 11‐year—old Pinus el1iottii stand. In the first growing season after needle initiation, N, P, K, Mg, and Zn concentrations decreased, but this was followed by an increase in the fall and winter months. Another drop in concentration of all elements, except P, occurred in the second growing season. Decreases in total contents indicated that this drop was a result of translocation to other tissues. In contrast to the mobile elements, the concentration and fascicle contents of Ca, Mn, and Al increased with aging of the needles.

Between‐tree variability was least for N, P, and Zn and the N, K, Mg, Mn, and Zn in the current foliage had consistently lower variation than that in the 1‐year‐old foliage. Between‐tree variation for K was lower in the winter than the spring.

For pine foliage, recommended sampling period for N, P, Mg, and Zn is mid to late summer and for the other elements it is late fall to late winter.

There are several sources of variation that influence the level of nutrients in tree foliage. The most important of these, apart from the tree nutrient status, are seasonal fluctuations, variation between trees, and age of needles . Smaller sources of variation are associated with position of the needles within the crown, diurnal changes, year to year variation, and analytical errors1,2. These variables must be studied in order to develop suitable sampling techniques and in Pinus this has been undertaken for P. banksiana 1, P. taeda 3, P. strobus 4, P. resinosa 4, P. sylvestris 5, and P. radiata 6,7. However, foliage sampling has not been studied in detail for slash pine (Pinus elliottii Englem var. elliottii) and earlier studies with other pines have been largely confined to temperate or cool climates.

This study reports the variation in elemental concentrations with season, age of foliage, and between slash pine trees growing in a subtropical climate in Florida.  相似文献   

14.
Abstract

The phytotoxicity of five nonessential elements (Co, V, Ti, Ag, Cr) to higher plants was studied in solution culture experiments with bush beans (Phaseolus vulgaris L. C.V. Improved Tendergreen). All, but in varying degrees, tended to concentrate in roots with a decreasing gradient to stems and leaves. Cobalt was one of the more mobile of the five trace metals. Its toxicity was expressed as severe chlorosis; 43 (with 10‐5 M) and 142 (with 10‐4 M) μg Co/g dry weight in leaves resulted in severe chlorosis. Vanadium as 10‐4 M vanadate resulted in smaller plants but not in chlorosis. Leaf, stem, and root V, respectively, were 13, 8, and 881 μg/g dry weight. Titanium was somewhat mobile with considerable yield decrease at 10‐4 M; leaf, stem, and root Ti concentrations, respectively, were 202, 48, and 2420 μg/g. Symptoms were chlorosis, necrotic spots on leaves, and stunting. Silver was very lethal at 10‐4 M AgNO3; at 10‐5 M yields were greatly decreased, but plants were grown without symptoms. Leaf, stem, and root concentrations of Ag for this treatment, respectively, were 5.8, 5.1, and 1760 μg/g dry weight. Plants grown with 10‐5 N Cr2O7 were decreased in yield by about 25% with or without EDTA (ethylenediamine tetraacetic acid) while the same level of Cr2(SO4)3 was essentially without effect. For the two salts, the leaf, stem, root concentrations for Cr, respectively were 2.2 and 1.3, 0.7 and 0. 7, and 140 and 104 μg/g. Most of the trace metals studied here had interactions in the uptake and/or distribution of other elements.  相似文献   

15.
A general method is described for determining 16 mycotoxins in mixed feeds and other food products used in the manufacture of these feedstuffs. The mycotoxins are extracted and cleaned up by extracting with solvents of different pH. Thin layer chromatography is used to separate the toxins; toxins are then quantitated by the limit detection method. The minimum detectable concentration of mycotoxins in various products is: aflatoxin B1 or G1, 4--5 micrograms/kg; ochratoxin A or ethyl ester A 140--145 micrograms/kg; citrinin 600--750 micrograms/kg; zearalenone, 410--500 micrograms/kg; sterigmatocystin, 140--145 micrograms/kg; diacetoxyscirpenol, 2400--2600 micrograms/kg; T-2 toxin, 800--950 micrograms/kg; patulin, 750--800 micrograms/kg; penitrem A 14,000--14,500 micrograms/kg; penicillic acid 3400--3650 micrograms/kg.  相似文献   

16.
A total of 244 samples of cereals (wheat flour, rice, and maize), pulses (arhar, moong, gram, lentil, and black gram), spices (turmeric, chili, coriander, and black pepper), vegetables (potato, onion, spinach, cabbage, brinjal, and tomato), fruits (mango, guava, apple, and grape), milk, butter, Deshi ghee, and edible oils (vegetable, mustard, groundnut, and sesame) collected from different cities of Northern Province (Utter Pradesh) were analyzed by gas liquid chromatography for the presence of organochlorine pesticide residues. Residues of hexachlorocyclohexane (HCH) and 2,2-bis(p-chlorophenyl)-1,1,1-trichloroethane (DDT) were detected in about 85% of the total samples of cereals, spices, milk, butter, Deshi ghee, and edible oils analyzed in the present study. However, the residue levels were either very small (less than 0.06 ppm) or not detected at all in pulses, vegetables, and fruits as compared with very high concentrations in wheat flour (4.42 and 0.12 ppm), butter (1.19 and 4.85 ppm), mustard oil (1.26 and 2.42 ppm), Deshi ghee (1.10 and 3.84 ppm), vegetable oil (1.02 and 0.59 ppm), groundnut oil (0.51 and 1.49 ppm), and chili (0.48 and 1.92 ppm). The levels of HCH and DDT residues detected in rice, maize, turmeric, corlander, black pepper, and all the vegetables and fruits were also lower than those found in wheat flour, oil, and fat samples analyzed in the present study. These findings suggest that a restricted and controlled use of such persistent pesticides may be useful for decreasing their contamination levels in different food items.  相似文献   

17.
Different procedures have been proposed to decompose soil samples. Most of them regard determination with fertility aims. In this case, the contents available to the plants are considered. On the other hand, there are procedures to determine total content. The objective of this work was to propose a new decomposition procedure to determine barium (Ba), cobalt (Co), chromium (Cr), copper (Cu), manganese (Mn), nickel (Ni), vanadium (V), and zinc (Zn) total content in tropical soils with high content of oxides and silicate. According to the results, the digestion procedure proposed in this study provided satisfactory results for the contents recovery for the elements Ba, Co, Cr, Cu, Mn, Ni, V, and Zn, above 90%, and the use of inverted aqua regia, hydrogen peroxide (H2O2), hydrofluoric acid (HF), pre-digestions and agitation was shown as a new alternative for the high silicate content soil sample total digestion, such as the oxisols.  相似文献   

18.
Abstract

The objectives of this study were 1) to recommend reference values (RVs) and tolerance limits (TLs) for representative Brazilian soils and 2) to propose a model to calculate natural contents of cadmium (Cd), cobalt (Co), chromium (Cr), copper (Cu), nickel (Ni), lead (Pb), and zinc (Zn) in a soil from the silt, clay, manganese (Mn), iron (Fe), and cation exchange capacity (CEC) values. A set of 256 soil samples was classified by similarity in seven groups, and the concentrations corresponding to the upper quarter of data collected were then calculated. These concentrations are proposed as RVs for Brazilian soils. Additionally, TLs were obtained for each group from the antilog expression (m+2s), where m=mean value and s=standard deviation of data transformed in log10. The classification functions of discriminant analysis proved to be suitable to allocate new samples in the established groups. Thus, it is possible to evaluate soils under anthropic activity and, by comparison with reference values, to be aware of pollution risks in a given area.  相似文献   

19.
Amazonia, the world's largest tropical rain forest, is often assumed to be a virtually untouched wilderness. The region is often referred to as a demographic void; there is on average only about one person per sq. km. Yet in response to international market forces, the hand of man has penetrated deep into the imposing forests. Since colonial times, wildlife, particularly along rivers, has been exploited on a large-scale basis for commercial purposes. This paper focuses on the effects of the trade on some aquatic animals.  相似文献   

20.
The total phenolics and antioxidant activities of fenugreek, green tea, black tea, grape seed, ginger, rosemary, gotu kola, and ginkgo extracts, vitamin E, and tert-butylhydroquinone, were determined. Grape seed and green tea were analyzed for their phenolic constituents using high-performance liquid chromatography. The total phenolics of the plant extracts, determined by the Folin-Ciocalteu method, ranged from 24.8 to 92.5 mg of chlorogenic acid equivalent/g dry material. The antioxidant activities of methanolic extracts determined by conjugated diene measurement of methyl linoleate were 3.4-86.3%. The antioxidant activity of the extracts using chicken fat by an oxidative stability instrument (4.6-10.2 h of induction time) followed a similar trend in antioxidant activity as determined by the Folin-Ciocalteu method. Seven phenolics in grape seed and green tea extracts were identified that ranged from 15.38 to 1158.49 and 18.3 to 1087.02 mg/100 g of extract, respectively. Plant extracts such as green tea and grape seed extracts can be used to retard lipid oxidation in a variety of food products.  相似文献   

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