放牧影响下典型草原克氏针茅和多根葱根系属性比较

植物根系属性与其生态适应性密切相关.为明确不同放牧干扰下克氏针茅和多根葱两种优势植物根系属性差异,比较了轻度放牧、中度放牧、重度放牧下克氏针茅和多根葱地下根系长度、根系表面积、根系直径、根系体积、根尖数、根系分叉数、比根长和比表面积的形态特征,分析了2种植物根尖比、根长比、表面积比、体积比等根系形态格局,研究两种植物对...     

镉胁迫下玉米幼苗生理生态的变化

用不同浓度Cd2 + 处理玉米种子 ,在室内常规培养 ,研究了种子萌发和幼苗生理生态的变化。结果表明 ,镉影响玉米种子的萌发和幼苗的生长。当Cd2 + 浓度高于 5 0mg·L-1时 ,显著抑制种子的发芽率 ;随Cd2 + 浓度的增加 ,根系长度和侧根数减小 ;在Cd2 + 浓度小于 5mg·L-1时 ,镉刺激苗高和根系及地上部干物质量增加 ,当Cd2 + 浓度超过相应浓度时 ,苗高和根系及地上部的生长量随Cd2 + 浓度提高而降低。镉胁迫下幼苗根系活力和叶绿素含量明显降低 ,根内丙二醛含量增加。镉影响玉米幼苗对矿质元素的吸收。根系和茎叶中Ca、Mg、Fe、Cu的吸收量随Cd2 + 浓度提高而增加 ,K、Zn的吸收量随Cd2 + 浓度提高而减少。     

铜胁迫下甘蓝幼苗生长和铜吸收的基因型差异

采用盆栽土培法,对31个甘蓝品种苗期生长对铜胁迫的耐性及铜吸收和积累的差异进行了研究。结果表明,400 m g.kg-1Cu2+处理下,不同基因型甘蓝的耐性及吸收、积累铜的能力具有显著差异。地上部干重的抑制率变幅为-25.0%~95.7%,铜对地上部的抑制作用大于根系。根系Cu2+含量变幅为212~893 m g.k-g 1,地上部变幅为32~87 m g.kg-1,根系Cu2+含量显著高于地上部;根系Cu2+积累量变幅为5~78μg/盒,地上部变幅为8~116μg/盒。地上部Cu2+含量与地上部抑制率呈极显著的正相关。根据聚类结果,31个甘蓝品种分成3类,平均地上部干重抑制率分别为76.0%、40.3%和-2.1%,表明其分别属于铜敏感型、中间型和耐性型。     

城市垂直绿墙常用植物的根系构型特征和生长动态

以适应性强的2种常见藤本植物：夹竹桃科的花叶蔓长春(Vinca major‘Variegata’)和花叶络石(Trachelospermum jasminoides‘Variegatum’)为研究对象,每年随机选择5盆进行重复测试,比较它们2017—2021年的根系生物量、根冠比及根系的长度、表面积、直径、体积、根尖数等形态指标及比较各指标间的变异率和相关度,分析植物在垂直绿墙容器种植条件中根系的动态变化特征,以量化植物根系受根域限制而生长退化的时间节点和有效衡量指标,从而为延长绿墙使用寿命和开发低维护管养技术提供科学依据。结果表明：1) 2种植物的根系生物量及根长、根表面积、根体积、根分叉数、根尖数均在植物上墙后2019年达到峰值后开始下降,可作为衡量植物根系生长受根域限制而退化的时间节点;根冠比值在2020年达最低水平,反映了地下根系生长受限制早于所观测到的地上枝叶退化现象。2)根长、根表面积、根体积、根尖数均可作为衡量指标,其中,根系体积可作为典型的衡量指标,花叶蔓长春和花叶络石生长受限的根体积占比分别为2.2%、1.8%。3) 2种植物的根冠比与根长等构型特征指标呈一致的变化趋...     

樟树(Cinnamomum camphora)幼苗细根形态对氮磷添加和幼苗密度的响应

全球氮沉降对森林生态系统结构和功能的影响已成为现代生态学研究热点之一,我国华南地区氮沉降的增长引起了土壤酸化和磷限制加剧等一系列生态问题。密度制约着植物个体对环境资源的吸收利用,是自然界中十分重要的选择压力之一。因此研究樟树(Cinnamomum camphora)幼苗的细根形态对氮磷添加和密度的响应,有利于了解亚热带树木根系对氮沉降和磷添加与林分密度的响应过程和机制,并为全球变化背景下樟树林生态系统的管理提供依据。本研究以1年生樟树幼苗为试验材料,选择氯化铵(NH_4Cl)作为氮肥以模拟大气氮沉降,并且以二水合磷酸二氢钠(NaH_2PO_4·2H_2O)模拟磷添加,氮磷处理设置4个水平,即对照、施N、施P和施N+P;种植密度设置10、20、40和80株/m~2 4个水平。测定各处理樟树幼苗细根的根长、表面积、体积和根尖数,分析氮磷添加、密度和两者交互作用对樟树幼苗细根的影响。研究结果表明,与对照处理相比,N、P和N+P处理促进了幼苗细根长度、表面积、体积以及根尖数的增加。低密度条件下的N添加对幼苗根系形态的促进效果强于P添加。N+P处理对10、20、40株/m~2幼苗根系形态的促进效果最佳,而各处理对80株/m~2幼苗根系形态的促进效果均无显著性差异。随着种植密度的增大,幼苗细根长度、表面积、体积和根尖数均减少。樟树幼苗的细根长度、表面积、体积和根尖数在各密度间和不同氮磷添加处理间均有显著性差异,密度和氮磷处理间的交互作用对根系形态各指标均无显著影响。     

重金属胁迫对毛竹种子萌发及其富集效应的影响

以毛竹种子为供试材料,研究4种重金属(Pb2+、Zn2+、Cu2+、Cd2+)胁迫对毛竹种子萌发的影响,并考察重金属在毛竹幼苗各组织部分的富集情况。结果表明:(1)Pb2+和Cd2+对毛竹种子的发芽率、发芽势、发芽指数及活力指数有抑制作用,低浓度下Cu2+和Zn2+对毛竹种子的发芽势、发芽率、发芽指数等指标有促进作用,高浓度则显著抑制;当浓度达到1600μmol/L时Cd2+对种子萌发的抑制效果明显强于其他3种元素;(2)选取根尖数、根表面积、根体积、根系总长4个根系形态指标发现,低浓度处理下Pb2+、Zn2+对根系生长有促进作用,而Cu2+和Cd2+起到明显的抑制作用;(3)处理10d后,种子萌发幼苗地上部对Pb2+、Zn2+、Cu2+、Cd2+的含量最高可达6810.51、1387.77、951.77、429.33 mg/kg,转移系数Zn2+Cd2+Pb2+Cu2+。综上,系统揭示了毛竹种子在重金属胁迫下的萌发和富集情况,为今后的土培、大田试验提供了有益的参考,也为将毛竹作为植物修复材料加以研究开启了新的研究视角,具有重要的研究价值。     

空气断根对侧柏实生苗生物量分配和根系生长的影响

为探求林木幼苗生物量分配和根系生长对空气断根的响应,以侧柏(Platycladus Orientalis)实生苗为材料,设置空气断根(T)和不断根(CK)处理,研究了空气断根10、30 d和50 d后对侧柏生物量、根系形态特征及吸收面积的影响。结果表明:(1)T处理的侧柏幼苗地上生物量、根生物量、总生物量、根长、根表面积、根体积及根尖数在断根10、30 d和50 d后均大于CK,且显著扩大了根系总吸收面积和活跃吸收面积。(2)空气断根显著影响了侧柏实生苗的生物量分配格局,其根冠比在整个试验阶段呈先增大后减小的趋势,而CK逐渐减小。(3)两种处理的侧柏幼苗根系直径集中在0-0.5 mm。与CK相比,T处理侧柏随空气断根时间延长,单株根系直径在0-0.5 mm的根数量急剧增多,占总根尖数的79%,根平均长度、根表面积、根体积和根尖数显著增大。(4)生物量参数和根形态参数之间关系密切。根生物量与地上生物量及总生物量呈显著正相关(P0.05)。除根系平均直径外,根生物量、地上生物量和总生物量分别与根长、根表面积、根体积、根尖数呈显著正相关,根冠比与地上生物量呈负相关。因此,空气断根有效改善了侧柏幼苗的根系形态特征,提高了吸收面积,显著促进侧柏实生苗在生长早期快速发育。     

盐胁迫对弗吉尼亚栎生长及矿质离子吸收、运输和分配的影响

以低浓度(50 mmol.L-1)和高浓度(150 mmol.L-1)NaC l处理弗吉尼亚栎(Quercus virginiana)2年生扦插苗,研究了弗吉尼亚栎生长和根系形态学参数变化以及Na+、K+、Ca2+、Mg2+、NO3-等矿质离子在不同器官的吸收、运输和分配。结果表明,盐胁迫不同程度促进了地上部和根系生长,地上部和根系干重、根长、表面积和体积在低浓度盐胁迫下明显增加(P0.05),而在高浓度盐胁迫下变化不大。随着根系对Na+和C l-吸收的增加,K+、Ca2+、Mg2+在根部和茎部的积累明显降低,矿质离子由根部向茎部运输的能力在低浓度盐胁迫增加而高浓度下受到抑制。叶片在低浓度和高浓度盐胁迫下对K+、NO3-具有很强的选择吸收能力,这对于维持叶片离子平衡和正常的光合作用及代谢过程具有重要意义。Na+和C l-在根部的浓度远远大于地上部,说明弗吉尼亚栎根系对盐离子具有较高的耐受性,而减少盐离子在地上部的积累,对于维持地上部的正常生长具有重要意义,这也是弗吉尼亚栎对盐胁迫的适应机制之一。     

隔沟交替灌溉条件下玉米根系形态性状及结构分布

为揭示根系对土壤环境的适应机制,研究了隔沟交替灌溉条件下玉米根系形态性状及结构分布。以垄位和坡位的玉米根系为研究对象,利用Minirhizotrons法研究了根系（活/死根）的长度、直径、体积、表面积、根尖数和径级变化及其与土壤水分、土温和水分利用效率（WUE）的相关关系。结果表明,对于活根,在坡位非灌水区域复水后根系平均直径减小,而根系日均生长速率、单位面积土壤根系体积密度、根尖数和表面积均增大,并随灌水区域土壤水分的消退逐渐减小;对于死根,在坡位非灌水区域复水后根系日均死亡速率、根系体积密度、根尖数和表面积变化均减小,其中根系死亡速率和死根直径随土壤水分的消退逐渐降低,而死根体积密度、根尖数和表面积分布随土壤水分降低呈增大趋势;在垄位,根系形态分布趋势与坡位一致,除根系直径与与坡位比较接近外,其他根系形态值均小于坡位。将根系分成4个径级区间分析根系的形态特征,结果表明在根系长度和体积密度分布中以2.5－4.5 mm径级的根系所占比例最大,在根尖数和根系表面积分布中以0.0－2.5 mm径级的根系为主。通过显著性相关分析,死根直径、体积密度、活根表面积等根系形态与土壤含水率、土壤温度和WUE间均存在显著或极显著的正相关关系,部分根系形态指标（如根系的生长速率、活根体积密度）只与坡位土壤含水量、土壤温度具有明显的相关性,表明隔沟交替灌溉对坡位根系形态的调控作用比垄位显著。     

丛枝菌根真菌对砂培玉米幼苗根系特征、光合生理与镉累积的影响

【背景】丛枝菌根真菌(arbuscular mycorrhizal fungi,AMF)是一类重要的土壤微生物,能显著影响植物对镉(cadmium,Cd)的耐性与累积,但其对不同形态Cd胁迫的响应尚不清楚。【目的】探讨不同形态Cd胁迫下接种AMF对玉米(Zea mays L.)生长和Cd累积的影响。【方法】采用30 cm高的培养容器填装石英砂(0.2 mm),开展室内砂培玉米试验,研究溶解态和胶体态Cd (1 mg/kg)胁迫下,接种摩西斗管囊霉(Funneliformis mosseae)对玉米幼苗生长、根系特征、光合生理及Cd累积的影响。【结果】双因素分析表明,AMF和Cd形态均对玉米生长(株高和生物量)、根系特征、光合生理(叶绿素含量和光合速率)与Cd累积量存在显著的影响,但二者之间没有显著交互作用。与未接种处理相比,接种AMF显著降低玉米株高、生物量、叶片叶绿素含量和光合速率,抑制玉米根长、根表面积、根体积和根尖数;同时增加了玉米根系Cd含量,但减少玉米地上部Cd含量以及地上部与根系Cd累积量;与胶体态Cd处理相比,溶解态Cd显著降低玉米的根长、根表面积、平均根系直径、根尖数和地上部Cd累积量,但增加了植株叶片光合速率、根系Cd含量和累积量。相关分析发现,玉米根长、根表面积和根尖数与地上部Cd含量呈显著或极显著正相关,与根系Cd含量呈极显著负相关。【结论】溶解态Cd比胶体态Cd对砂培玉米幼苗的毒害效应严重,而且接种AMF加重溶解态和胶体态Cd对玉米幼苗的损伤,但降低了植株对Cd的累积。     

蚯蚓-秸秆及其交互作用对黑麦草修复Cu污染土壤的影响

以高沙土为供试土壤,加入Cu^2＋以模拟成：0,100,200,400mg／kgCu^2＋的Cu污染土壤,设置接种蚯蚓（E）、表施秸秆（M）,同时加入蚯蚓和秸秆（ME）及不加蚯蚓和秸秆的对照（CK）4个处理,并种植黑麦草。研究蚯蚓、秸秆相互作用对黑麦草吸收、富集铜的影响。结果表明：加入秸秆显著提高了蚯蚓的生物量,一定程度上缓解了重金属对蚯蚓的毒害,同时蚯蚓显著提高了秸秆的分解率,较无蚯蚓对照提高了58．11％～77．32％。接种蚯蚓（E,ME）还提高了土壤有效态重金属（DTPA-Cu）含量,秸秆处理（M）则降低了土壤有效态重金属含量。研究还发现,E处理促进了黑麦草地上部生长,而M和ME处理均显著提高了黑麦草地下部的生物量。E和ME处理同时提高了植物地上部和地下部的Cu浓度及Cu吸收量,M处理则只对植物的地下部Cu浓度和Cu吸收量有显著促进作用。总体来看,E处理、M处理及ME处理分别使黑麦草地上部Cu富集系数提高了31．22％～121．07％．2．12％～61．28％和25．56％～132．64％。     

Role of earthworm-straw interactions on phytoremediation of Cu contaminated soil by ryegrass

It is well known that the earthworm's activities can increase the availability of soil nutrients, improve soil structure, and enhance the biomass of plants in uncontaminated soil. Recently, many researchers found that some metal-tolerant earthworms can survive and even change the fractional distribution of heavy metals in contaminated soil. Furthermore, it has been revealed that earthworms are able to increase metal availability, and therefore, accumulate more metals in plants through their burrowing and casting activity. It is clear that the influence of soil animals is an important factor for phyto-remedation that must be taken into account. ~In this article, the authors studied some effects of addition of earthworms (Metaphire guillelmi), corn straw, and in combinations of earthworms and corn straw on the growth and Cu uptake by ryegrass in Cu contaminated pot soils. The experiment consisted of four levels of Cu addition (0, 100, 200, 400 mg·kg?1) and four treatments. The treatments were 1. control (CK); 2.straw mulching only (M); 3. earthworm additions to soil only (E); and 4.straw mulching plus earthworm additions (ME). Each treatment had three replicates. 10 seeds of ryegrass (Lolium multiflorum) were sowed in each pot and harvested after 30 days. After 30 days of incubation, all earthworms were found to be alive and the pot soils were burrowed through by earthworms. Results showed that the biomass of earthworm declined with the increase of the dosage of Cu additions. The biomass of earthworm increased significantly in treatment 4 (ME) as compared with treatment 3 (E). Not only the earthworms could get more food from the straw, but also could counteract some negative effects of Cu on the earthworms. The rates of straw decomposition in ME treatment increased by about 58.11% ?77.32%. The earthworm activities increased root biomass of ryegrass significantly, but did not show the effect on plant root growth. On the contrary, straw enhanced roots biomass significantly instead of shoots biomass. It was also found that the concentration of Cu in the plant shoot and the plant root, as well as plant Cu uptake were enhanced by earthworm's activities and straw mulching. The increased amount by straw mulching was lower than that of earthworms (E). The treatment of the earthworm–straw mulching combinations enhanced plant Cu concentration, and the amount increased by it was lower than that of the earthworm treatment (E) but higher than that of straw mulching treatment (M). The accumulation factors of copper in the shoots of ryegrass were increased by 31.22% ?121.07%, 2.12% ?61.28% and 25.56% ?132.64%, respectively, in treatment 3(E), 2(M), and 4(ME), respectively. In conclusion, the earthworm activities, straw-mulching and their interactions may have potential roles in elevating phyto-extraction efficiency in low to medium level Cu contaminated soil.     

Root turnover in pasture species: chicory,lucerne, perennial ryegrass and white clover

For pastures, root turnover can have an important influence on nutrient and carbon cycling, and plant performance. Turnover was calculated from mini‐rhizotron observations for chicory (Cichorium intybus), lucerne (Medicago sativa), perennial ryegrass (Lolium perenne) and white clover (Trifolium repens) grown in the Manawatu, New Zealand. The species were combined factorially with four earthworm species treatments and a no‐earthworm control. Split plots compared the effects of not cutting and cutting the shoots at intervals. Observations were made c. 18 days apart for 2.5 years. This article concentrates on differences between plant species in root turnover in the whole soil profile to 40 cm depth. At this scale, earthworm effects were generally small and short lived. For ryegrass and white clover, root length and mass were linearly related (R² = 0.82–0.99). For chicory and lucerne, the relationships were poorer (R² = 0.38–0.77), so for those species length turnover may be a poor indicator of mass turnover. Standing root length, total growth and death generally decreased in the sequence ryegrass > lucerne > chicory = white clover. In length terms, scaled turnover (growth divided by average standing root length) generally followed the sequence lucerne > white clover > perennial ryegrass = chicory. Across species the scaled turnover rate averaged 3.4 per year or 0.9% per day. Cutting shoots reduced standing root length, growth and death, but increased scaled turnover. These results indicate fast and prolonged root turnover. For ryegrass and white clover, at least there is need to reappraise how to measure and model shoot : root ratios, dry matter production and carbon cycling.     

Earthworm effect on root morphology in a split root system

Plants respond to their environment through adaptations such as root proliferation in nutrient-rich patches. Through their burrows and casts production in soil, earthworms create heterogeneity which could lead to local root adaptations or systemic effects. To investigate the effect of earthworms on root system morphology and determine whether earthworm effect is local or systemic, we set up two independent split root experiments with rice or barley, (i) without earthworm (CC), (ii) with earthworms in both compartments (EE), and (iii) with earthworms in one single compartment (CE). Earthworms had an effect on belowground plant biomass. The relative length of thick roots decreased with an increasing abundance of earthworms. Some root diameter classes responded to earthworm number in a linear or curvilinear way, making simple conclusions difficult. We found no difference in root biomass or morphology between the two compartments of the split root system in the CE treatment, but a positive effect of earthworm biomass on root biomass, volume, surface area, and length at the whole plant level. Results supported a systemic effect dependent on earthworm abundance. Modification of nutrient mineralization, soil physical structure, and/or the concentration of signal molecules could all be responsible for this systemic effect.     

The effect of sulfur supply on the root characteristics of subterranean clover and annual ryegrass

Summary The root characteristics and sulfur absorption of Trikkala sub-clover and Wimmera ryegrass were compared in a pot experiment in which plants were grown at two levels of sulfur supply (0 and 64 mgS/pot) for a period of 40 days after emergence.Ryegrass roots had a greater weight and root weight ratio, but a lower sulfur content than sub-clover roots at both levels of sulfur supply. Ryegrass roots were longer, had a greater length per unit weight, longer root hairs, and hence a larger volume and surface area than sub-clover roots. However, when the sulfur content in the whole plant was related to the root parameters, sub-clover absorbed a far greater amount of sulfur, irrespective of whether the content was expressed on the basis of the weight, length, volume or surface area of the roots.Sulfur application had relatively little effect on the morphology of roots of either species. However, whilst sulfur application increased the weight of both shoots and roots, it decreased the root weight ratio for sub-clover but not for ryegrass. Increasing sulfur supply reduced the total length of sub-clover roots but tended to increase the length of ryegrass roots. For both species, the length per unit weight of roots decreased, and the average root diameter increased, with increasing sulfur supply. Sulfur application decreased the volume and surface area of sub-clover roots, but increased these parameters in ryegrass roots.     

Temporal and spatial patterns of soil water following wildfire-induced changes in plant communities in the Great Basin in Nevada,USA

Infection of tall fescue (Festuca arundinacea Schreb.) with its endemicNeotyphodium coenophialum-endophyte (Morgan-Jones and Gams) Glenn, Bacon and Hanlin appears to reduce copper (Cu) concentrations in forage and serum of grazing animals, contributing to a range of immune-related disorders. A greenhouse experiment was conducted to identify effects of novel endophyte strains on Cu acquisition by tall fescue (Festuca arundinacea Schreb.) varieties Grasslands Flecha and Jesup infected with a novel, non ergot producing endophyte strain AR542, and two perennial ryegrass (Lolium perenne L.) varieties Aries and Quartet infected with a novel, non lolitrem B producing strain AR1, and their noninfected (E−) forms. Individual endophyte/grass associations were cultivated in nutrient solutions at 1.0 (P+) and 0.0 mM (P−) phosphorus concentrations. The Cu²⁺-binding activity of extracellular root exudates, and concentrations of Cu and other heavy metals in roots and shoots were measured. Extracellular root exudates of AR542-infected vs. E− tall fescue had higher Cu²⁺-binding activity only in P− nutrient solution as shown by lower concentration of free Cu²⁺ (0.096 vs. 0.188 mmol Cu²⁺ g⁻¹ root DM, respectively). The Cu²⁺-binding activity by root exudates of perennial ryegrass was not affected by endophyte infection, but was higher (i.e., lower concentration of free Cu²⁺) in P− vs. P+ nutrient solution (0.068 vs. 0.114 mmol Cu²⁺ g⁻¹ root DM). In this hydroponic experiment, Cu concentrations in shoots of both grasses were not a function of Cu²⁺-binding activity and endophyte effects on heavy metal concentrations in shoots and roots were specific for each variety. The Cu²⁺-binding activity of extracellular root exudates may affect Cu accumulation by field-grown, endophyte-infected tall fescue under P-limiting growth conditions and warrants verification by more specific methods.     

Some soil-plant and root-shoot relationships of copper,zinc and manganese in white clover and perennial ryegrass

Summary White clover and perennial ryegrass were grown separately, in pots maintained under controlled environment conditions, for a period of 7 months on ten soils. The proportion of the total soil content of each element taken up by the ryegrass, including that in roots, ranged from 0.88 to 2.18% for Cu, from 0.82 to 2.80% for Zn and from 0.25 to 3.15% for Mn. Uptake by the clover was within these ranges for Cu and Zn, but ranged from 0.10 to 1.71% for Mn.After adjustment for the effects of soil contamination, the ratio of root concentration: shoot concentration was always greater than 1 for both Cu and Zn, and for Cu, though not for Zn, it was considerably greater with ryegrass than with clover. For Mn, the ratio of root:shoot concentration was often greater than 1, and differences between clover and grass were not consistent.Concentrations of Cu and Zn in the shoots were always greater in the clover than in the grass, but concentrations of Mn were generally greater in the grass than the clover.     

老化和风干处理对蚓粪微生物学性质和结构稳定性的影响

蚓粪水稳性团聚体含量是结构稳定性表征之一,蚓粪中水稳性团聚体含量与其微生物学性质是紧密联系的,并且受到老化时问和有机质等因素的影响。国内将蚓粪水稳性团聚体含量与其微生物学性质联系,并结合施用不同有机物处理的研究很少见报道。研究通过室内短期培养试验,研究了在不同碳氮比有机物施用下蚓粪老化和风干处理对其微生物生物量、微生物活性和结构稳定性变化的影响。研究结果表明蚓粪经过老化处理后真菌数量、微生物生物量碳和微生物活性都显著降低。不同有机物的施用对蚓粪微生物学性质的影响主要表现在施用牛粪的处理中蚓粪细菌数量高于施用秸秆的处理,真菌数量相反。新鲜蚓粪经过老化处理后总的水稳性团聚体含量（〉0．053mm）增加,主要表现在水稳性大型大团聚体（〉2mm）含量增加,且在施用牛粪的处理中达到显著,可能是与牛粪比秸秆能分解产生更多的粘结物质有关。蚓粪的风于处理也显著增加各个处理中总水稳性团聚体含量,且风干后蚓粪中水稳性团聚体主要以微团聚体（0．25～0．053mm）形式存在。施用秸秆的处理中,新鲜蚓粪0．25～0．053mm粒级的水稳性团聚体含量显著高于施用牛粪的处理。经风干后,施用秸秆的处理0．25～0．053mm的水稳性团聚体含量显著低于施用牛粪的处理,而水稳性大型大团聚体含量显著高于施用牛粪的处理。蚓粪的不同粒级水稳性团聚体含量和蚓粪的生物学性质之间存在良好的相关性。     

Absorption and Distribution of Copper in Plants with Sufficient or Deficient Supplies

Wheat, red clover and ryegrass were grown in flowing solutionculture with sufficient (+ Cu) and deficient (–Cu) suppliesof copper. The rates of Cu absorption (µg g^–1 dryroot day^–1) did not differ greatly between species ineither treatment. Wheat plants, when transferred from the –Cu to the +Cu treatment, absorbed Cu at a much slower rate thanthose which had remained throughout in the + Cu treatment. Inall plants considerable proportions of the absorbed Cu wereretained in the roots, even when the plants were Cu-deficient,and the concentration in roots usually exceeded that in anypart of the shoots in both treatments. Transferring wheat plantsfrom the +Cu to the –Cu treatment decreased the concentrationin all plant parts except old leaves; similarly, transferringfrom the –Cu to +Cu treatment increased the concentrationin all parts of the shoots, execept old leaves, and in the roots. Lolium perenne, Trifolium pratense, Triticum aestivum, ryegrass, red clover, wheat, absorption, copper, flowing solution culture