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1.
铅镉高污染土壤的钝化材料筛选及其修复效果初探 总被引：8，自引：1，他引：7
本研究以重金属高污染农田土壤(全Pb含量为1 277 mg/kg,全Cd含量为39.0 mg/kg)为研究对象,通过土培试验和玉米苗期盆栽试验,探讨海泡石、石灰、腐植酸、钙镁磷肥、磷矿粉、生物质炭等常用稳定材料不同剂量及复配组合对高污染土壤重金属的钝化修复效应。土培试验结果表明,石灰对Pb和Cd钝化效果最好,其次是海泡石,但两者表现为较高添加量处理间没有显著差异;而低剂量生物质炭和腐植酸显著增加土壤有效态Pb和Cd含量,高剂量生物质炭具有较好的钝化效果。盆栽试验表明,海泡石与石灰配施钝化效果较好,与对照相比,土壤氯化钙提取态Pb、Cd含量分别降低了97.5%、81.4%;玉米根和地上部Cd含量分别降低48.5%、34.0%,Pb含量分别降低35.6%、29.6%;但海泡石与磷材料配施显著增加玉米根Pb含量,对玉米Cd吸收没有显著影响。以上结果表明,重金属高污染农田土壤添加合适的改良剂,可较大幅度降低土壤重金属有效性和植物重金属吸收性。 相似文献
2.
不同施用量石灰和生物炭对稻田镉污染钝化的延续效应 总被引：3，自引：1，他引：3
为筛选适用于西南地区稻田土壤及农作物Cd污染的修复技术,采用田间小区试验比较了单施石灰、生物炭以及复合施用石灰+生物炭及其不同用量对Cd污染稻田的土壤基本理化性质、稻米Cd含量及其水稻各部位富集转运的影响。结果表明:第1年修复试验中,单施石灰和生物炭以及复合施用均可降低稻米Cd含量以及水稻各部位富集和转运系数,且随着施加量的增加稻米Cd含量呈降低趋势,土壤至水稻根系Cd富集系数呈先降低后增加趋势,复合施用(石灰(1.5 t/hm^2)+生物炭)效果优于单施石灰和生物炭,与对照相比,稻米Cd含量降低57.14%~88.57%,土壤至水稻根系富集系数降低22.06%~32.96%;施用石灰可显著提高土壤pH和降低土壤有效态Cd含量。第2年修复剂施用延续效应试验中,石灰在短时间内降低土壤有效Cd和稻米Cd的效果较好,但其长效性和稳定性不及生物炭,与对照相比,单施石灰和生物炭以及复合施用土壤有效Cd分别降低2.97%~25.19%,13.94%~23.41%,1.93%~21.41%,稻米Cd含量分别降低0.72%~34.87%,12.11%~49.14%,36.55%~51.71%。总体来看,设定试验条件下,复合施用(石灰(1.5 t/hm^2)+生物炭(3.0 t/hm^2)),效果最优。 相似文献
3.
生物质炭施用对马铃薯产量和品质的影响 总被引：4，自引：0，他引：4
通过田间试验,观测分析不同生物质炭用量(0、20和40 t/hm~2)下马铃薯产量、品质和土壤肥力的变化及其年际效应,为生物质炭在马铃薯生产过程中的应用提供理论依据。结果表明,低剂量生物质炭施用(20 t/hm~2)显著提高了马铃薯总产量和商品率,生物质炭施用后第一年马铃薯总产量比对照提高了41.08%。当生物质炭用量为40 t/hm~2时,马铃薯产量与对照没有显著差异但降低了一些品质指标,其中2016年干物质和淀粉含量比对照降低了18.47%和24.03%。生物质炭施用显著提高了土壤有机碳、有效磷和速效钾含量,并增加了土壤C/N和电导率;而对土壤p H和全氮含量的影响与生物质炭施用年限有关。生物质炭施用量和施用年限显著影响马铃薯产量和品质。低剂量生物质炭施用能显著提高马铃薯产量,但第二年无增产效果;随着生物质炭用量增加马铃薯增产效果消失,还可能会降低马铃薯品质。生物质炭施用后马铃薯产量变化与土壤紧实度改善无必然联系。 相似文献
4.
生物质炭对土壤-水稻系统中Cd迁移累积的影响 总被引：3，自引：2，他引：1
探究生物质炭添加对Cd污染土壤中Cd形态、植株对Cd的吸收分配及土壤肥力的影响,为污染稻田粮食安全提供科学依据。在湖南省长沙市Cd污染稻田进行田间定位试验,设置5个生物质炭添加量处理(0,10,20,30,40t/hm^2),分析生物质炭对Cd在土壤中形态转化和水稻器官中分配的影响。结果表明:生物质炭通过将土壤中酸溶态Cd钝化为可还原态Cd以减少在水稻器官中的累积,钝化量随着生物质炭增加而增加,土壤酸溶态Cd较CK降低3.83%～19.08%;且茎对根和糙米对茎的转运系数随生物质炭的添加分别降低4.23%～9.30%和1.39%～8.33%;土壤酸溶态Cd含量直接影响糙米中Cd含量,且受土壤pH和土壤有机碳的调控。Cd污染稻田添加生物质炭可以提高土壤肥力,降低土壤Cd生物有效性,20t/hm^2生物质炭添加量可以作为研究区周边Cd污染稻田修复的参考标准。 相似文献
5.
生物质炭施用对潮土理化性状、酶活性及黄瓜产量的影响 总被引：4，自引：0，他引：4
分析生物质炭施用对潮土理化性状、酶活性及黄瓜产量的影响,为生物质炭在农业中的推广应用提供科学依据。以如皋市农业科学研究所大棚示范区为试验基地,通过田间小区试验,研究了不同生物质炭施用量(0,5,10,20,30,40t/hm~2)条件下土壤理化性状、酶活性及黄瓜产量变化。结果表明:生物质炭施用对土壤理化性状及土壤酶活性有显著的影响。高施用量(40t/hm~2)处理对土壤物理性状的改良效果最好,当生物质炭施用量为30t/hm~2时对土壤养分含量提升效果最好。与对照相比,施用生物质炭各处理土壤容重降幅为0.88%~10.52%,而土壤孔隙度、饱和含水量、田间持水量、饱和导水率、有机质、全氮、硝态氮、铵态氮和速效磷含量的增幅分别为3.68%~7.53%,27.96%~119.25%,30.73~55.05%,1.89%~224.61%,10.39%~54.56%,6.06%~22.58%,2.33%~45.63%,235.71%~414.29%和19.37%~77.76%。土壤脲酶和过氧化氢酶的活性及黄瓜产量随着生物质炭施用量的增加均呈先增加后降低的趋势,两种酶的活性分别在生物质炭施用量为30t/hm~2和20t/hm~2时最大,较对照分别提高了104.57%和15.38%;生物质炭施用量为30t/hm~2时对黄瓜增产效果最好,该处理下黄瓜产量较对照提高了21.80%。主成分分析结果表明,不同生物质炭施用量处理下的土壤质量次序为C4C5C3C2C1CK。在土壤中施用生物质炭不仅可以促进黄瓜增产,改善土壤理化性状,提高土壤养分含量,还可以改良土壤生物学性质,提升土壤酶活性。 相似文献
6.
生物质炭与氮肥配施对旱地红壤微生物量碳、氮和碳氮比的影响 总被引：10，自引：4，他引：10
以江西典型旱地红壤为研究对象,设置生物质炭和氮肥2个因素(生物质炭4个水平分别为0t/hm~2,5t/hm~2,20t/hm~2,40t/hm~2;氮肥4个水平分别为0kg/hm~2,60kg/hm~2,90kg/hm~2,120kg/hm~2),研究了生物质炭施入大田3a后对旱地红壤微生物量碳、氮及碳氮比的影响。结果表明:与对照相比,生物质炭与氮肥配施有效地提高了土壤微生物量碳,提高幅度为18.22%~122.74%,对土壤微生物量氮的提高效果更为明显,提高幅度为20.86%~312.91%。生物质炭与氮肥配施后土壤微生物碳氮比有不同程度的降低,降低幅度为18.11%~51.56%,其中以20t/hm~2生物质炭与60kg/hm~2氮肥以及40t/hm~2生物质炭与120kg/hm~2氮肥的比例施用后对微生物碳氮比的降低效果最为明显。因此,通过生物质炭与氮肥配施可以提高旱地红壤中微生物量碳、氮及土壤氮素生物活性。 相似文献
7.
钝化剂对酸性高镉土壤钝化效果及水稻镉吸收的影响 总被引：4，自引：2，他引：4
以海泡石、磷酸二氢钾、钙镁磷肥、钢渣、生石灰及生物炭为重金属镉钝化材料,研究钝化剂对湖南省酸性高镉(Cd)稻田土壤及水稻中Cd含量的影响。以土壤pH值和有效态镉作为评价指标,筛选出三种效果较优的钝化剂,通过正交试验进行复配,选择最优的钝化剂配方进行田间验证。结果表明,海泡石、钙镁磷肥、钢渣在施用比例为1%时均可显著提高土壤pH,pH的提升效果排序为钢渣钙镁磷肥海泡石;除钢渣外,其余钝化剂在施用比例为1%时均可不同程度降低土壤有效态Cd含量,钝化效果排序为磷酸二氢钾钙镁磷肥生物炭海泡石生石灰。选取海泡石、钙镁磷肥和磷酸二氢钾复配钝化剂,依据正交试验结果并综合考虑钝化效果、成本及材料易得性,确定钝化剂的最优施用量组合为海泡石500 mg kg-1、钙镁磷肥500 mg kg-1、磷酸二氢钾170 mg kg-1。大田试验结果表明,施用钝化剂后,土壤pH值提高0.5个单位,土壤有效Cd含量降低34.00%,糙米中Cd含量降低19.44%,水稻各器官Cd的富集与迁移系数明显降低,水稻产量明显升高。 相似文献
8.
《土壤通报》2017,(6):1423-1428
为了解生物质炭施于旱地红壤较长时间后对土壤物理、化学及微生物特性的影响,以江西典型旱地红壤为对象,采用田间长期定位试验的方法观察了不同用量生物质炭(0、2.5、5、10、20、30 t hm~(-2)和40 t hm~(-2))在施用4年后旱地红壤基础理化性质、土壤微生物生物量碳、氮、土壤基础呼吸强度及微生物商、微生物代谢熵等的变化。结果表明,施用生物质炭4年后,旱地红壤pH、有机碳、全氮、微生物生物量碳和生物量氮均随生物质炭施用量的增加呈上升趋势,土壤容重、微生物碳氮比呈下降趋势。以生物质炭用量40 t hm~(-2)时的改良效果最好,与对照相比,土壤容重显著(P0.05)降低了0.17 g cm-3,微生物碳氮比显著降低了7.97,土壤pH、有机碳、全氮、微生物生物量碳和生物量氮分别显著提高了6.1%、47%、21.5%、43.3%和162.6%。试验证明施用生物质炭较长时间后对旱地红壤的改良效果依旧良好,并且生物质炭施用量越高,对土壤理化性质和微生物特性的影响越显著。 相似文献
9.
[目的]探讨不同生物质炭施用量条件下旱地红壤中NO-3-N的含量及水平运移规律,为该地区的农田水分管理和环境保护提供科学依据。[方法]采用室内水平扩散率仪测定不同生物质炭施用量[C0(0t/hm~2,不施用生物质炭),C1(2.5t/hm~2),C2(5t/hm~2),C3(10t/hm~2),C4(20t/hm~2),C5(30t/hm~2)和C6(40t/hm~2)]条件下土壤中硝态氮水平运移速率和运移浓度。[结果]生物质炭施用对土壤中硝态氮的水平运移速率和水平运移浓度影响显著。随着生物质炭施用量的增加,硝态氮的水平运移速率和水平运移浓度呈先增加后降低的趋势,而土壤水扩散率呈逐渐降低趋势。C5(30t/hm~2)处理下硝态氮的水平运移速率和水平运移浓度均出现最大值,分别为0.67cm/min,165.52mg/kg。随着生物质炭施用量的继续增加,C6(40t/hm~2)处理的硝态氮的水平运移速率和水平运移浓度较C5(30t/hm~2)处理有所降低,硝态氮浓度最大值均出现在湿润峰峰面上。分析影响硝态氮水平运移规律的因素表明,生物质炭降低了土壤的容重、增加了土壤有机碳和孔隙度,从而导致了各处理硝态氮的水平运移规律发生了变化。[结论]生物质炭可以改善土壤的理化性状,促进硝态氮的水平运移,在利用生物质炭改良旱地红壤理化性状的同时,也要注意防止氮素流失对环境的影响,降低其对地表水的潜在污染风险。 相似文献
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采集浙江杭州郊区富春江沿岸镉(Cd)污染水稻土，选择前期试验筛选的对土壤Cd钝化效果良好、可显著降低稻米Cd的4种调理剂，开展室内培养试验和温室盆栽试验，探讨不同调理剂种类(袁梦YM、祝天峰ZTF、天象一号TX1、永清YQ)、用量(推荐用量、3倍推荐用量)和调理剂与生石灰配施对污染水稻土Cd的稳定效果及对水稻生长和糙米Cd含量的影响。室内培养试验结果发现，添加调理剂能使土壤pH显著升高，落干条件下土壤pH增幅较淹水条件下更为明显；施用推荐用量调理剂，土壤硝酸铵提取态Cd显著下降，调理剂推荐用量+生石灰处理较调理剂推荐用量处理下降更为显著；总体上，同一调理剂3倍推荐用量处理下硝酸铵提取态Cd降幅更大，表明硝酸铵提取态Cd受土壤pH影响显著，且YM、TX1调理剂对硝酸铵提取态Cd的降低效果较好。盆栽试验结果显示，施用石灰和商品调理剂均可实现水稻稳产或增产，并显著降低水稻糙米Cd含量，与调理剂施用后土壤Cd有效性降低相一致。含钙、能调节土壤pH并辅以有机质和养分的复合调理剂因兼具养分作用，对水稻稳产增产、糙米Cd含量降低更为有效。 相似文献
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【目的】以富士（Fuji）、 秦冠（Qinguan）嫁接在平邑甜茶（Malus hupehensis Rehd.）上的当年生盆栽苗为试验材料,采用砂培方法,研究了缺氮胁迫和干旱对富士和秦冠生长情况、 光合参数、 植株各部位氮磷钾含量及氮素利用效率的影响,分析比较了低氮干旱条件下富士和秦冠生长及氮素利用的差异,以期为果树生产高效肥水利用提供理论指导。【方法】试验共设四个处理: 正常氮正常水（ZZ）、 低氮正常水（DZ）、 正常氮干旱（ZG）、 低氮干旱（DG）。氮素和水分均设置两个水平,分别为正常氮（6 mmol/L NO-3-N）、 低氮（0.3 mmol/LNO-3-N）、 正常供水（保持盆中砂子相对含水量为饱和含水量的80%~85%）、 干旱处理（保持盆中砂子相对含水量为饱和含水量的60%~65%）。【结果】富士和秦冠的生物量（茎和叶）、 株高茎粗等生长指标以及光合速率、 气孔导度、 蒸腾速率均为正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）,并且相对应处理下秦冠的以上指标均高于富士;正常供水下,缺氮处理使富士、 秦冠的根冠比比正常氮处理均有所增加,富士提高了2.05%,秦冠提高了22.40%。富士和秦冠的氮、 磷、 钾含量均表现出正常氮正常水（ZZ）＞低氮正常水（DZ）＞正常氮干旱（ZG）＞低氮干旱（DG）; 氮、 钾元素含量在植株各部位的分布顺序依次是叶＞根＞茎,磷元素则是根＞叶＞茎;光合氮素利用效率（PNUE）和氮素利用效率表现为秦冠处理之间差异极显著,富士处理之间差异不显著;秦冠的PNUE和NUE明显高于富士,在低氮正常水（DZ）处理下,秦冠氮肥利用率比富士高42.07%,在低氮干旱（DG）处理下高64.14%;低氮胁迫下富士和秦冠的NUE显著提高,并且秦冠提高的幅度高于富士。【结论】施用氮肥能够显著提高富士与秦冠的干物质量,同等水肥条件下,秦冠生长优于富士;水分亏缺会减少叶片对氮的吸收,干旱条件下适度增施氮肥,可提高果树的抗旱能力;低氮干旱胁迫下秦冠的生长指标、 光合指标及氮素利用效率指标均优于富士,表现出较强的抗低氮干旱胁迫的能力。 相似文献
12.
Kyle Devey Michael Mucalo Gordon Rajendram Joseph Lane 《Communications in Soil Science and Plant Analysis》2015,46(4):72-80
Laser-induced breakdown spectroscopy (LIBS) is a new technique for the analysis of plant material. This study investigates the application of LIBS to pasture-based plant samples. The LIBS measurements were obtained from pelletized pasture samples (100 samples) that had been also analyzed by inductively coupled plasma–optical emission spectroscopy (ICP-OES) following microwave digestion for calibration and comparison purposes. Comparisons for elements sodium (Na), potassium (K), magnesium (Mg), calcium (Ca), manganese (Mn), iron (Fe), copper (Cu), zinc (Zn), boron (B), phosphorus (P), and sulfur (S) showed that LIBS could be used for almost all the standard profile total elements with concentrations down to low mg/kg levels (observed error of Na: 0.024 percent, K: 0.18 percent, Mg: 0.016 percent, Ca: 0.073 percent, P: 0.017 percent, Mn: 31 mg/kg, Fe: 150 mg/kg, Zn: 6.6 mg/kg, and B: 1.1 mg/kg). Elemental analysis at less than mg/kg levels was not possible using LIBS. The elements S and Cu were particularly difficult to analyze with reliability using LIBS at the concentration levels found in the plant samples. Replacing microwave digestion and subsequent ICP analysis with a direct analysis of dried plant samples using LIBS has the potential to improve the productivity and reduce the cost of testing. 相似文献
13.
《中国生态农业学报》2014,(8)
正The Center for Agricultural Resources Research(CARR),the Institute of Genetics and Developmental Biology(IGDB),Chinese Academy of Sciences,invites applicants for several research group leader positions.CARR is one of the research organizations in Chinese Academy of Sciences(CAS).We seek nominations and applications from individuals who have expertise and a record of accomplishment in research areas related to ecology,agro-hydrology, 相似文献
14.
M.A. Callaham Jr. J.M. BlairT.C. Todd D.J. KitchenM.R. Whiles 《Soil biology & biochemistry》2003,35(8):1079-1093
The responses of tallgrass prairie plant communities and ecosystem processes to fire and grazing are well characterized. However, responses of invertebrate consumer groups, and particularly soil-dwelling organisms, to these disturbances are not well known. At Konza Prairie Biological Station, we sampled soil macroinvertebrates in 1994 and 1999 as part of a long-term experiment designed to examine the effects and interactions of annual fire, mowing, and fertilization (N and P) on prairie soil communities and processes. For nearly all taxa, in both years, responses were characterized by significant treatment interactions, but some general patterns were evident. Introduced European earthworms (Aporrectodea spp. and Octolasion spp.) were most abundant in plots where fire was excluded, and the proportion of the total earthworm community consisting of introduced earthworms was greater in unburned, unmowed, and fertilized plots. Nymphs of two Cicada genera were collected (Cicadetta spp. and Tibicen spp.). Cicadetta nymphs were more abundant in burned plots, but mowing reduced their abundance. Tibicen nymphs were collected almost exclusively from unburned plots. Treatment effects on herbivorous beetle larvae (Scarabaeidae, Elateridae, and Curculionidae) were variable, but nutrient additions (N or P) usually resulted in greater densities, whereas mowing usually resulted in lower densities. Our results suggest that departures from historical disturbance regimes (i.e. frequent fire and grazing) may render soils more susceptible to increased numbers of European earthworms, and that interactions between fire, aboveground biomass removal, and vegetation responses affect the structure and composition of invertebrate communities in tallgrass prairie soils. 相似文献
15.
Grete Skrede Berit Karoline Martinsen Anne-Berit Wold Stein-Erik Birkeland Kjersti Aaby 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2013,63(3):193-208
Abstract A 3-year study was carried out to investigate quality parameters in 14 tree fruit and berry species grown in southern Norway. The species were blueberry, apple, aronia, sour cherry, sweet cherry, red raspberry, strawberry, blackcurrant, gooseberry, red currant and elderberry, harvested along with wild bilberry, cloudberry and lingonberry. Significant differences between species were identified for all quality parameters. The coefficient of variation between species was lowest for pH (12.5%), dry matter (18.9%) and soluble solids (25.3%), followed by titratable acids (59.3%), total phenolics (83.8%), antioxidant capacity FRAP (85.7%) and antiradical power by the DPPH-assay (97.8%), total monomeric anthocyanins (132%) and ascorbic acid (137%). Average coefficient of variation within species were lower and ranged from 4 (pH) to 62% (ascorbic acid). Only the FRAP values were significantly affected by harvesting year with lower levels in 2004 than in 2005 and 2006. There were significant interactions between species and harvesting year for dry matter, soluble solids, pH, ascorbic acid and FRAP. The results indicate generic ranges in composition within species independent upon growing location and climate, and the composition of the tree fruits and berries is not likely to deviate from these ranges. It is concluded that desirable composition of tree fruits and berries and their products should primarily be achieved by selection among species rather than searching fors broadened variation within individual species. 相似文献
16.
《Communications in Soil Science and Plant Analysis》2012,43(7):865-877
Potassium (K) fixation and release in soil are important factors in the long-term sustainability of a cropping system. Changes in K concentration and characteristics of K fixation and release in rhizosphere and nonrhizosphere soils in the rapeseed (Brassica napus L.)–rice (Oryza sativa L.) rotation were investigated using a rhizobox system. The concentrations of different forms of K in both rhizosphere and nonrhizosphere soils decreased with plants compared to without plants, regardless of K fertilizer application. Potassium uptake by crops mainly came from the rhizosphere soil. In the treatment without K fertilizer (–K), the main form of K supplied by the soil to the crops was 1.0 mol L?1 nitric acid (HNO3) nonextractable K, followed by nonexchangeable K, and then exchangeable K. In the treatment with K fertilizer (+K), the main K forms supplied by the soil to the crops were exchangeable K and nonexchangeable K. The amount and rate of K fixation after one cycle of the rapeseed–rice rotation was greater in rhizosphere soil than in nonrhizosphere soil. The amount and rate of K fixation of soil in the +K treatment were significantly less than in the –K treatment. The cumulative amounts of K released with 1.0 mol L?1 ammonium acetate (NH4OAc) and 1.0 mol L?1 HNO3 extraction increased with the increasing numbers of extractions, but the K-releasing power of soil by successive extraction decreased gradually and finally became almost constant. The release of K was less in rhizosphere soil than in nonrhizosphere soil. The release of K in the +K treatment was similar to that in the –K treatment in rhizosphere soil, but the K release in nonrhizosphere soil was greater with the +K than the –K treatment. Overall, the information obtained in this study will be helpful in formulating more precise K fertilizer recommendations for certain soils. 相似文献
17.
Electron donor and pH relationships for biologically enhanced dissolution of chlorinated solvent DNAPL in groundwater 总被引：3，自引：0，他引：3
Biologically enhanced dissolution offers a method to speed removal of chlorinated solvent dense non-aqueous-phase liquid (DNAPL) sources such as tetrachloroethene (PCE) and trichoroethene (TCE) from aquifers. Bioremediation is accomplished by adding an electron donor to the source zone where fermentation to intermediates leading to acetic acid and hydrogen results. The hydrogen and possibly acetic acid are used by dehalogenating bacteria to convert PCE and TCE to ethene and hydrochloric acid. Reductive dehalogenation is thus an acid forming process, and sufficient alkalinity must be present to maintain a near neutral pH. The bicarbonate alkalinity required to maintain pH above 6.5 is a function of the electron donor: 800 mg/L of bicarbonate alkalinity is sufficient to achieve about 1.2 mM TCE dechlorination with glucose, 1.7 mM with lactate, and a much higher 3.3 mM with formate. Laboratory studies indicate that in mixed culture, formate can be used as an electron donor for complete conversion to ethene, contrary to pure cultures studies indicating it cannot. Various strategies can be used to add electron donor to an aquifer for DNAPL dehalogenation while minimizing pH problems and excessive electron donor usage, including use of injection-extraction wells, dual recirculation wells, and nested injection-extraction wells. 相似文献
18.
Aleš Lebeda Ivana Doležalová Eva Křístková Barbora Mieslerová 《Genetic Resources and Crop Evolution》2001,48(2):153-164
Staff members of the Department of Botany of Palacký University in Olomouc and Gene Bank Department – Workplace Olomouc, Research Institute of Crop Production in Prague, Czech Republic, conducted an expedition in seven European countries (Austria, Czech Republic, France, Germany, Italy, the Netherlands, Switzerland) in August/September 1999 to collect wild Lactuca spp. germplasm and study its geographic distribution, ecology and biodiversity. During the mission, more than 600 locations were visited resulting in the collection of 602 seed samples (accessions) of wild Lactuca species and 13 seed samples of related genera (Chondrilla and Mycelis). Lactuca serriola f. serriola, L. serriola f. integrifolia, L. saligna and L. viminea subsp. chondrilliflora were prevalent in southern Europe (Italy, France), however, only L. serriola was common in central and western Europe (Austria, Czech Republic, Germany, Netherlands, Switzerland). The greatest diversity of Lactuca species was found in France, where also the most seed samples (165) were collected. The most characteristic habitats with a high density of Lactuca spp. populations were observed along roads and highways, grassy ditches, ruderal communities, and dust-heaps. Natural infections by powdery mildew (Erysiphe cichoracearum) and downy mildew (Bremia lactucae) on some wild Lactuca spp. were observed. Recent observations concerning the geographic distribution, population structure, habitats, and natural occurrence of diseases of Lactuca spp. are discussed. This assemblage of genetic resources of Lactuca spp. can serve as the basis of future studies of species diversification, spatial population structure, plant microevolution, domestication processes, and genetic variability of host-parasite interactions. 相似文献
19.
Y. Bashan J. J. Bustillos L. A. Leyva J.-P. Hernandez M. Bacilio 《Biology and Fertility of Soils》2006,42(4):279-285
Inoculation of wheat seedlings with the plant growth-promoting bacterium Azospirillum brasilense Cd was immobilized in alginate microbeads and, without applying any stress, significantly increased the quantity of several
photosynthetic pigments, such as chlorophyll a, chlorophyll b, and the auxiliary photoprotective pigments violaxanthin, zeaxanthin, antheroxanthin, lutein, neoxanthin, and β-carotene.
This resulted in greener plants with no apparent visible stress. After monitoring the quantity of photosynthetic pigments
for 4 weeks, we observed that inoculated plants had higher quantities of pigments in shoot and stem. The greatest difference
in the quantity of all pigments between inoculated and noninoculated plants occurred in the first week of growth. Regardless
of treatment, the quantity of pigments in stems was three to four times less than the quantity of these pigments in shoots.
Application of Azospirillum, either as liquid inoculant or as alginate microbeads, did not alter the positive effect of the bacteria on pigment production
or the positive response of the plants towards A. brasilense Cd inoculation. 相似文献
20.
Three slow-growing legume trees used for desert reforestation and urban gardening in the Sonoran Desert of Northwestern Mexico
and the Southwestern USA were evaluated whether their growth can be promoted by inoculation with plant growth-promoting bacteria
(Azospirillum brasilense and Bacillus pumilus), unidentified arbuscular mycorrhizal (AM) fungi (mainly Glomus sp.), and supplementation with common compost under regular screenhouse cultivation common to these trees in nurseries. Mesquite
amargo (Prosopis articulata) and yellow palo verde (Parkinsonia microphylla) had different positive responses to several of the parameters tested while blue palo verde (Parkinsonia florida) did not respond. Survival of all tree species was over 80% and survival of mesquite was almost 100% after 10 months of cultivation.
Inoculation with growth-promoting microorganisms induced significant effects on the leaf gas exchange of these trees, measured
as transpiration and diffusive resistance, when these trees were cultivated without water restrictions. 相似文献