外来入侵植物紫茎泽兰对土壤养分的影响

选取云南、四川省3个不同生境作为样地,研究紫茎泽兰入侵对不同生态系统土壤中碱解氮、速效磷、速效钾含量的影响.结果表明,紫茎泽兰入侵造成样地a土壤碱解氮、速效磷、速效钾含量分别显著下降33.9%、44.2%和32.2%;样地b仅土壤速效磷显著下降31.0%;样地c土壤各营养元素未见显著变化.在不同时间,样地a处理组各营养元素含量基本低于对照组,以2005年7月至10月的差异最显著.这说明紫茎泽兰入侵对土壤养分的影响因生境不同而异,且与紫茎泽兰的生长节律有关.     

接种Glomus versiforme对红三叶草利用有机磷的影响

以红三叶草为材料，利用三室隔网培养方法，研究接种菌根真菌Glmous versiforme对土壤有机磷及外加有机磷化合物植酸钠（Na-Phytate)、核糖核酸（RNA）和卵磷脂（Lecithin)的利用效率，植株生长7wk后收获测定植标干物重、含磷量和根系菌根侵染率，结果表明：接种菌根真菌能明显增加植株干物重、含磷量和吸磷总量，与各有机磷处理相比，无机磷（KH2PO4）处理生长效应最好，施用有机磷化合物各处理与CK相比均明显促进了植株生长，但不同有机磷处理之间没有显著差异，在植株吸磷量上，各接种处理均为相应CK处理的2倍以上，其中磷酸二氢钾处理吸磷量最高，菌根对照植物的根外菌丝虽然被限制在有限的空间内，但其吸磷量也达到不施磷的CK－M处理的2倍多，这说明由于菌根的形成植物能利用土壤因有的有机磷来满足自身生长的需要，表3参10     

不同土壤水分条件下添加硅对紫花苜蓿茎叶和土壤氮磷钾含量的影响

为提高植物氮磷钾利用能力,采用盆栽试验研究了不同土壤水分条件下添加硅对紫花苜蓿(Medicago sativa)茎叶和土壤氮、磷、钾含量的影响.结果表明,土壤含水量为饱和含水量的35%和80%时添加硅对紫花苜蓿生物量没有明显影响,而土壤含水量为饱和含水量的50%和65%时则显著提高了紫花苜蓿生物量(P<0.05);添加硅对紫花苜蓿茎叶内氮含量没有显著影响,但显著提高了茎叶内钾和磷含量(P<0.05);添加硅对土壤全氮、速效氮、全钾和全磷含量没有显著影响,而显著提高了土壤速效磷含量(P<0.05),显著降低了土壤速效钾含量(P<0.05).说明添加硅能够显著增加紫花苜蓿茎叶内磷和钾的积累量,刺激土壤速效磷释放,降低土壤速效钾含量.     

4种替代植物对黄顶菊入侵土壤养分和酶活性的影响

入侵植物对土壤环境的影响是植物竞争取胜的重要生态策略之一,而选择合适的植物可以替代控制和抵御外来植物的入侵。比较了高丹草、向日葵、紫花苜蓿和多年生黑麦草4种植物与黄顶菊单种和混种后不同时期的土壤养分和土壤酶活性变化规律。结果表明：（1）黄顶菊单独种植根区土壤NH4＋-N、NO3-N含量均显著低于紫花苜蓿和黄顶菊混种群落,其有效磷含量显著低于高丹草和黄顶菊混种群落;（2）紫花苜蓿和黄顶菊混种群落土壤脲酶、磷酸酶、蔗糖酶活性均显著高于黄顶菊单种群落。因此,在本试验条件下,高丹草、紫花苜蓿对土壤氮素转化利用能力比黄顶菊高,且能竞争性抑制黄顶菊对土壤磷素的吸收,利于实现对黄顶菊的替代控制。     

Effects of fly ash, Pseudomonas striata and Rhizobium on the reproduction of nematode Meloidogyne incognita and on the growth and transpiration of pea

Glasshouse experiments were conducted twice to assess the ash amendments (0, 20, and 40% with soil), a phosphate solubilizing microorganism Pseudomonas striata and a root-nodule bacterium Rhizobium sp on the reproduction of root-knot nematode Meloidogyne incognita and on the growth and transpiration of pea. Amendments of fly ash with soil had no effect on transpiration. However, M. incognita reduced the rate of transpiration from 1st week onward after inoculation while inoculation of Rhizobium sp and P. striata increased transpiration from 1st week onward after their inoculation both in nematode inoculated and uninoculated plants. Increase in transpiration was greater when both organisms were inoculated together. Addition of 20 and 40% fly ash with soil was beneficial for plant growth both in nematode inoculated and uninoculated plants. Inoculation of above organisms also increases plant growth of nematode inoculated and uninoculated plants in different fly ash soil mixture but increase in growth was greater when both organisms were inoculated together. Use of 20% fly ash increased galling and nematode multiplication over plants grown in without fly ash while 40% fly ash had adverse effect on galling and nematode multiplication. Rhizobium sp had greater adverse effect on galling and nematode multiplication than P. striata. Use of both organisms together had greater adverse effect on galling and nematode multiplication than caused by either of them alone. Highest reduction in galling and nematode multiplication was observed when both organisms were used in 40% fly ash amended soil. However, highest transpiration was observed in plants without nematodes and inoculated with both organisms together both in with or without fly ash amended soil.     

西南环境移民安置地的生态环境状况研究初报

以桂西北环江县肯福环境移民安置示范区为例，对我国西南喀斯特地区环境移民安置区的气候、地貌、土壤与植被等主要生态因子进行了调查研究和取样分析。研究表明，环境移民安置地由于地处亚热带季风气候区，具有气候温暖，雨量充沛，日照充足，且雨热同季的特点；地貌破碎，土地以坡地为主，但有一定量可开垦利用的土地；土壤主要为红壤，土壤剖面发育良好，土壤质地和结构尚可，有机质和氮含量相对丰富，但磷、钾缺乏，土壤酸度大；植被以先锋植物为主。     

Nanotechnology-based controlled release of sustainable fertilizers. A review

The rising population is increasing food demand, yet actual crop production is limited by the poor efficiency of classical fertilizers. In particular, only about 40–60% of fertilizer nitrogen, 15–20% of phosphorus and 50–60% of potassium are used by crop plants, the rest ending polluting the environment. Nanofertilizers are promising alternatives. Here, we review plant nutrients, synthesis of zinc oxide nanoparticles, encapsulation of nanoparticles in fertilizers, and effect on plants.

     

污泥土地利用对土壤中重金属形态的影响

土地利用是资源化利用城市污水厂污泥的有效途径，随污泥中的营养成分一起进入土壤中的还有其中的重金属元素，它们有可能成为一种环境安全的隐患。本实验所用的土壤为污泥经过无害化及稳定化处理后，与上海潮滩沙土按不同比例(干污泥质量比)混配而成。种植前后分别对沙土、污泥及混配土的重金属含量及形态进行测试。选择几种花卉植物，如菊花(Calendula officinalis）等进行植物种植试验，一个生长季后对植物中的重金属含量及形态进行测试。应用Tessler连续提取法，对污泥中的重金属进入土壤后，土壤中重金属的含量、赋存状态等方面的规律进行研究，发现污泥的土地利用会明显增加土壤中的重金属含量，而且重金属的形态也有明显的变化，可交换态和碳酸盐结合态的重金属含量有明显的增加；如长期使用，则必须采取相应的措施，以消除有害的影响。     

Uptake and translocation of phosphorus in eelgrass (Zostera marina)

The uptake and translocation of phosphorus in eelgrass (Zostera marina L.) was studied in two-compartment chambers using ³²P and autoradiography. Eelgrass was able to take up phosphorus both with leaves and rootrhizomes. Only a small amount (less than 4%) of the total amount of phosphorus taken up from either source was translocated within the plants during an incubation time of 120 h. Release of translocated phosphorus from the plant tissues to the surrounding water was not detected. The autoradiographs showed that the translocated phosphorus was localized mainly in the actively growing plant tissues, i.e. the stem and young leaves, and nodes of the rhizomes and young roots. The uptake of phosphorus in leaves and the bidirectional translocation in the plants was significantly lower in the dark. The uptake of phosphorus in rootrhizomes was unaffected by light-conditions. The concentration of phosphate in the water of one compartment did not affect the phosphorus uptake by the plant parts in the opposite compartment. However, the translocation was significantly reduced when both compartments were supplied with identical phosphate concentrations. The results of the present investigation indicate that the quantitative significance of eelgrass in the cycling of phosphorus between sediment and water may have been greatly overestimated in earlier studies. The amount of phosphorus taken up by root-rhizomes and subsequently translocated to leaves is probably insignificant during most of the growing season in comparison to the amount taken up by the leaves from the surrounding water. However the uptake of phosphorus by root-rhizomes may be significant in the nutrition of eelgrass during periods with low phosphate levels in the water.     

The Role of Macrophytes in the Retention of Phosphorus in the River Thame,England

The effects of the growth of the dominant species of macrophytes on phosphorus transport in the River Thame, a nutrient enriched lowland clay catchment in southern England, were assessed using a mass-balance approach. Macrophyte abundance was estimated between late March and early June at three sites along the river. the plant biomass of phosphorus and the total phosphorus content of sediments in the main part of the river channel and sediments associated with the plant roots were measured on each occasion. Total phosphorus concentrations in the river water were measured at weekly intervals at a gauging station at the lower end of the study reach.

The results showed that the phosphorus content of plants at the site most impacted by sewage derived phosphorus was < 1% of the flux of total phosphorus estimated for the water column in April and May. Phosphorus contained in the total standing crop of macrophytes at the least impacted site was estimated as approximately 3% of the mean daily flux of total phosphorus in the water. Although no trends were found in the total phosphorus contents of the roots, shoots or sediments through the season, differences in the phosphorus content of the sediments were found between sites with different phosphorus loading. Higher porewater and Equilibrium Phosphate Concentrations (EPC_oS) were recorded at the site most impacted by sewage effluent when compared to an upstream sampling site.     

VA菌根对喀斯特草本群落植物根际养分影响研究

以贵州花江喀斯特高原生态综合治理试验示范区内草本群落阶段的几种主要植物为材料,对其根际微生态环境进行了研究,包括根际土壤化学性质、土壤酶活性和VA菌根侵染率及AMF孢子密度。结果表明：VA菌根侵染率和根际土壤中AMF孢子密度存在极显著正相关,相关系数达到0.97;不同植物根际土壤的化学指标和土壤酶活性均表现出较强的根际效应,即R/S〉1;VA菌根侵染率与pH值存在显著负相关,与有效磷质量分数存在极显著正相关,与碱性磷酸酶存在显著正相关,说明VA菌根能够促进土壤中难溶态磷往有效磷方向转化;AMF对宿主植物的侵染能够在一定程度上改善根际微生态环境的营养状况。     

加勒比松幼林追肥试验研究

加勒比松1a生幼林氮磷钾不同配比的追肥试验表明，追肥后6a，肥效都极显著；其中以第2a的效果最显著，最大树高、胸径、材积分别比不追肥增加39．1％～52．6％、45．4％～109．3％和34．1％～405．6％；6a后肥效下降，但追肥仍比不追肥的树高、胸径、材积增长8．7％～20％、10．9％～17．9％、31．5％～54．7％。氮磷钾配合施用的效果最佳，施氮磷而缺钾有负效应。当氮磷钾相同配比（N30P30K30）时有特殊的低效应。     

二氧化碳浓度升高对植物入侵的影响

从入侵植物和入侵植物群落两个方面,综述了大气二氧化碳浓度升高对植物入侵的影响。二氧化碳浓度升高,可以增加C3植物的入侵性,提高入侵植物的生物量、资源利用率以及繁殖能力,直接影响植物入侵;还可以通过改变土壤水分、氮循环、干扰体系等其它环境因子间接地影响植物入侵。此外,二氧化碳浓度升高,对入侵群落的初级生产量、组成与结构以及群落动态产生重要影响,改变群落的可入侵性。今后应当着重从群落水平,结合其它全球变化因子的共同作用研究二氧化碳浓度升高对植物入侵的影响,同时深入探讨其作用机制以及不同植物类群对二氧化碳的响应,为入侵种的预防和控制提供理论指导。     

Studies on the influence of mycorrhiza on the growth and physiology of Vigna unguiculata and Abelmoschus esculentus

Diverse forms of microorganisms present in the soil and near the roots of plants, which play a vital role in numerous physiological processes, have attracted the attention of scientists. The dynamic microbial associations may be saprophytic, pathogenic, or symbiotic. The most widespread symbiosis of plants is the mycorrhizal association between root-inhabiting fungi and the feeder roots of plants. The present study was conducted to study the effects of arbuscular mycorrhizal fungi on mineral nutrition of Vigna unguiculata and Abelmoschus esculentus. The experiment comprised of uninoculated seedlings and seedlings inoculated with Glomus mosseae. The chlorophyll a, chlorophyll b, total chlorophyll, carotenoid, protein, nitrate, nitrogen, and phosphorus content showed an increase in vesicular arbuscular mycorrhiza fungus-treated seedlings compared to non-mycorrhizal plants. The total soluble sugars and soluble starch content in leaves of all selected plant species in the present study showed a decrease in mycorrhizal seedlings compared to non-mycorrhizal seedlings.     

Effects of gasoline engine emissions on health status of auto rickshaw drivers at DIR (L) Khyber Pukhtunkhwa

A total of 50 blood samples were collected from auto rickshaw drivers who were exposed to environmental gasoline in different sites of Dir (L), Khyber Pukhtunkhwa, Pakistan, in July and August, 2009. Control group was selected among the individuals who were not regularly exposed to gasoline emissions. The samples were analyzed for calcium, cholesterol, glucose, phosphorus, potassium, and triglycerides levels. A significant increase was found in the blood levels of calcium, glucose, phosphorus, and triglycerides. A significant decrease was detected in the blood levels of potassium without any significant effect on the blood levels of cholesterol and magnesium.     

梯级河滩湿地模型对受污染河水氮磷和CODCr的净化效果

在贾鲁河畔构建3组并联的梯级河滩湿地模型,引种9种不同类型的湿地植物进行筛选试验,将湿地模型串联运行比较研究3种不同植物配置的梯级湿地对受污染河水的净化效果,在此基础上设定12h和24h等两组不同水力滞留时间,研究延长滞留时间对水质净化效果的影响。试验结果表明：对氮磷和有机物的去除效果挺水植物明显好于沉水植物,其中茭草（Zizania caduciflora）、荆三棱（Scirpus fluviatilis）和狭叶香蒲（Typha angustifolia）去除效果最好;沉水植物和挺水植物对氨氮的去除表现好于浮叶植物;延长水力滞留时间对改善水质净化效果明显,滞留时间由12h延长到24h后,TN、TP、氨氮和CODCr去除率分别提高10.2%、21.7%、30.2%和12.9%,对氨氮的净化效果改善最为明显;挺水植物＋沉水植物＋浮叶植物组合较单纯挺水植物组合在对氨氮和TN去除效果方面表现出较明显的优势,主要是由于不同类型湿地植物所营造的好氧、厌氧环境提高了对氨氮和TN去除效果。研究结果证明在湿地植被组建中,根据进水水质,应灵活选择植物种类,进行合理的植物配置,可提高湿地的净化效果。     

酸雨对土壤营养元素迁移转化的影响

针对近年来北方一些城市大气污染严重并导致部分月份出现酸雨,及酸雨对主要营养元素产生影响的实际情况,通过模拟pH=5.6的酸雨的淋溶实验,对土壤营养元素迁移转化规律作了较深入的研究。结果表明,土壤中硝态氮质量分数随土壤深度的增加而呈下降的趋势;土壤中速效磷、速效钾对酸雨不敏感;拟合出在土壤表层(<5 cm)、10 cm、20 cm、30 cm的不同深度,硝态氮随时间变化的迁移规律方程。     

氮钾配合施用对亚种间杂交水稻养分吸收及产量影响的研究

氮促进亚种间杂交稻的分蘖和对磷、钾的吸收,钾也能促进氮、磷的吸收,但对分蘖似有抑制的趋势。稻株各生育期氮、磷、钾含量以分蘗盛期最高。随后迅速下降,至幼穗形成期下降速率减缓。齐穗后,累积在茎、叶的氮、磷大部分向穗部转移,而钾则很少运送到穗部。每生产100kg稻谷约需吸收1.71kg N、0.77kg P_2O_5、2.30kg K_2O,三者比例为1:0.45:1.35。氮、钾配合施用的增产效果大于单施氮或钾的效果;在施用量为82.5kg N ha~(-1)和75.0kg K_2O ha~(-1)的基础上,增施氮肥或钾肥,其增产效果相近,表明在施用适量氮肥的前提下,亚种间杂交稻对钾的反应甚为敏感。     

苏南丘陵地区森林土壤酶活性季节变化

研究了苏南丘陵区不同林分土壤养分、酶活性的剖面分布以及酶活性的季节动态变化特征。研究结果表明,研究区土壤偏酸性,土壤中TN质量分数较高,有机质、TK、AK质量分数中等,TP、AP质量分数较低,土壤TN、有机质、AK、AP的质量分数及蔗糖酶、脲酶、H2O2酶、磷酸酶活性随着土壤深度的增加而逐渐降低。土壤酶活性在不同季节也存在差异,蔗糖酶活性的季节变化表现为：秋季〉夏季〉春季〉冬季,脲酶活性为：夏季〉春季〉秋季〉冬季,毛竹林土壤的磷酸酶活性为：秋季〉春季〉夏季〉冬季,其它3种林分土壤的磷酸酶活性为：秋季〉夏季〉春季〉冬季,H2O2酶活性在马尾松、麻栎、毛竹林土壤内表现为：春季〉秋季〉夏季〉冬季,在杉木内林土壤内表现为：春季〉夏季〉秋季〉冬季。在α=0.01或α=0.05水平下,土壤酶活性与土壤TN、AP、AK、有机质及重元素Pb、Cu、Zn、Cr、Ni呈显著或极显著相关,与土壤容重呈显著或极显著负相关,冬季蔗糖酶与其它3个季节的蔗糖酶呈现极显著或显著正相关;秋季磷酸酶与其它3个季节的磷酸酶呈现极显著或显著正相关;夏季脲酶与其它3个季节的脲酶呈现极显著正相关;夏季H2O2酶与其它3个季节的H2O2酶呈现极显著正相关。     

氮磷钾对寒害腰果植株恢复生长结果的影响

通过观测不同施肥处理区寒害腰果植株重新开花坐果状况,分析施肥对寒害腰果植株恢复生长的影响,并分析腰果叶片养分含量与结果量之间的关系。结果表明:氮对寒害腰果植株重新开花的花枝数影响最大,钾次之,磷影响最小,随着氮施用量的增加,植株的花枝数逐渐增大;氮是影响寒害腰果植株结果量的主要因素,植株结果量随着氮施用量的增加而增加,磷、钾各处理间的结果量均未达到统计上显著差异;在施氮肥的基础上,配施磷钾肥,可以提高寒害腰果植株结果量,9个施肥处理中以N3P3K2处理的结果量最多。