杨树林地处理生活污水生态效应

为了研究不同污水水力负荷对不同杨树品种人工林的影响,选择了‘I-72’、‘欧美107’、‘中林2001’与‘中林46’四个杨树品种,分别按照3、6、9、12、15 cm·周~(-1)5个水力负荷进行污水处理;测定试验期间各品种地上部分生长量、凋落物量与污染物积累量。结果表明:3~9 cm·周~(-1)水力负荷增加了‘I-72’、‘中林2001’、‘欧美107’的生长量、凋落物量与污染物积累量;水力负荷大于9 cm·周~(-1)时,这3个杨树品种生长量、凋落物量与污染物积累量随着水力负荷增加而降低。在这3个品种中,‘中林2001’年生长量与污染物积累量最大,‘欧美107’中等,‘I-72’最低。从杨树生长量与污染物积累量来看,‘中林2001’最适合作为污水处理的植物材料,其次是‘欧美107’、I-72杨,污水处理的适宜水力负荷为6~9 cm·周~(-1),‘中林46’不适合用于污水处理。     

温度与MgCl2对罗布白麻种子发芽和幼苗生长的影响

以罗布白麻( Apocynum pictum)为研究材料,通过设置不同温度和不同浓度的MgCl2处理,研究温度和MgCl2对罗布白麻种子萌发的影响,以探究其对镁质盐碱环境的适应性。结果表明：在低浓度 MgCl2(≤100 mmol.L-1⁾处理下,罗布白麻种子发芽率、发芽速率和发芽势普遍较高,且温度对其发芽几乎没有影响,而高浓度的MgCl2(≥ 200 mmol.L-1⁾对罗布白麻的发芽和幼苗根长芽长的生长有显著抑制作用 (P < 0.05)；温度显著地影响了罗布白麻种子和幼苗对高浓度MgCl2的耐受,25/10℃条件下罗布白麻所耐受的MgCl2的临界浓度和极限浓度达到最大。在春末夏初种植罗布白麻可能是盐碱地上的治理Mg土壤污染的一种有效方法。研究结果不仅丰富了对罗布白麻生态适应性的了解,也为镁质盐碱土的生态恢复、土地利用以及水土保持提供了理论依据。     

Phytoaccumulation of chromium by some multipurpose-tree seedlings

A pot culture experiment was conducted in green house to study the potential of chromium (Cr) phytoaccumulatory capabilities of four promising agroforestry tree species viz., Albizia amara, Casuarina equisetifolia, Tectona grandis, and Leucaena luecocephala. Possibility of enhancement of Cr uptake by chemical (citric acid) and biological vesicular arbuscular mycorrhizal fungi (VAM) amendments were also tried. Biologically stable speciation of Cr trivalent (Cr(III) and hexavalent Cr(VI) were used. Cr(VI) was more toxic to the tree growth in terms of collar diameter (CD) increment in all the tree species than Cr(III). In general, roots accumulated more Cr than shoots in all the tree species. There was more than 10 fold increase in root Cr content in comparison with shoot Cr content in all the trees at all the concentration of Cr and all sources of Cr. Citric acid significantly increased the Cr content in the tissues of roots in all the species under both speciation of Cr. The highest increase in Cr content brought by 20 mM citric acid addition was in A. amara. Unlike citric acid, VAM treatment did not bring about a significant increase in the Cr content of all the tree species studied. Results suggest that Albizia amara is a potential Cr accumulator with citric acid as soil amendment. The potential of this tree as a Cr phytoaccumulator may be investigated in long-term studies.     

植物修复技术治理土壤重金属污染的机制研究进展及其应用前景

植物修复技术是依据植物从环境中积累重金属元素和化舍物的能力及其将这些有毒物质在植物体内代谢成无毒生物小分子的能力而建立的新的生物技术。通过植物修复的植物稳定、植物挥发、植物提取3种类型,分别阐述了其中植物修复技术治理重金属的机制,尤其是超积幕植物内部物质与重金属的螯合作用以及金属螯合蛋白的生物合成与基因调控。目前,植物修复技术在土壤重金属治理中是一种高效、廉价和颇具潜力的原位绿色技术,具有广阔的应用前景。     

重金属和有机污染土壤植物增效修复技术研究进展

目前,土壤重金属和有机物污染状况愈发严重,受到了越来越多国内外学者的关注.植物修复技术是新近发展起来的一项用于处理土壤重金属、有机物污染的绿色技术,也是当前研究的热点领域.该文综述了植物修复技术在重金属、有机物及重金属-有机物复合污染土壤修复治理中的应用,包括螯合诱导修复、表面活性剂增效修复等,最后提出该技术目前存在的一些问题及发展方向.     

蚯蚓和丛枝菌根真菌对南瓜修复多环芳烃污染土壤的影响

在温室盆栽实验条件下,研究接种AM(arbuscular mycorrhiza)真菌、蚯蚓(Eisenia fetida)对南瓜(Cucurbita moschata)修复3环以上多环芳烃(PAHs)污染农田土壤的影响,试验设置单接AM真菌、单接蚯蚓、双接AM真菌和蚯蚓、不接种的对照共4个处理,播种10周后收获。结果表明,接种AM真菌和蚯蚓促进AM真菌侵染南瓜,增加南瓜生物量;显著提高南瓜修复土壤中Phe(菲)、An(t蒽)、Py(r芘)、BkF(苯并(k)荧蒽)、BaP(苯并(a)芘)、BPe(r苯并(g,h,i)苝)等PAHs污染物的效率,促进南瓜高效地吸收3~5环PAHs,尤其是AM真菌和蚯蚓共同接种条件下对南瓜修复土壤效果最优;AM真菌利于南瓜转移根系吸收的高浓度PAHs化合物至地上部,降低PAHs对根系的胁迫,增强南瓜在高浓度PAHs污染土壤中存活,有利于南瓜应用于高浓度PAHs污染土壤的高效修复;蚯蚓对南瓜地下部吸持3~5环高分子量的PAHs化合物有积极作用。因此,选用的AM真菌和蚯蚓在土壤中具有协同作用,促进南瓜高效修复PAHs污染土壤。     

Enhanced phytoremediation of multi-metal contaminated soils by interspecific fusion between the protoplasts of endophytic Mucor sp. CBRF59 and Fusarium sp. CBRF14

The aim of this study was to isolate protoplasts from different metal resistant endophytic fungi and to carry out interspecific fusion of protoplasts to enhance bioremediation of contaminated soils. Three stable fusants (F1, F2, and F3) with resistance to Cd and Zn were constructed by interspecific fusion between inactivated protoplasts from Cd-resistant endophytic Mucor sp. CBRF59 and Zn-resistant endophytic Fusarium sp. CBRF14. The fusants increased concentrations of water soluble Cd, Pb, and Zn in soils, promoted rape growth, increased metal concentrations in the rape, elevated the extractable metal amount, and increased metal translocation from roots to shoots in soils containing single metals or multi-metals. Especially, the fusants showed much higher extraction efficacy than the parents in soils contaminated by multi-metals. The results indicated that protoplast fusion should be a feasible and efficient fungal method, which could be utilized to construct stable fusants by combining the genetic traits of parents for bioremediation of contaminated soils by multi-metals.     

Enhancement of arbuscular mycorrhizal fungus (Glomus versiforme) on the growth and Cd uptake by Cd-hyperaccumulator Solanum nigrum

Arbuscular mycorrhizal fungus (AMF) can enhance plant growth and resistance to toxicity produced by heavy metals (HMs), affect the bioavailability of HMs in soil and the uptake of HMs by plants, and thus has been emerged as the most prominent symbiotic fungus for contribution to phytoremediation. A greenhouse pot experiment was conducted to assess the effect of Glomus versiforme BGC GD01C (Gv) on the growth and Cd accumulation of Cd-hyperaccumulator Solanum nigrum in different Cd-added soils (0, 25, 50, 100 mg Cd kg⁻¹ soil). Mycorrhizal colonization rates were generally high (from 71% to 82%) in Gv-inoculated treatments at all Cd levels. Gv colonization enhanced soil acid phosphatase activity, and hence elevated P acquisition and growth of S. nigrum at all Cd levels. Moreover, the presence of Gv significantly increased DTPA-extractable (phytoavailable) Cd concentrations in 25 and 50 mg Cd kg⁻¹ soils, but did not affect phytoavailable Cd in 100 mg Cd kg⁻¹ soil. Similarly, inoculation with Gv significantly increased Cd concentrations of S. nigrum in 25 and 50 mg Cd kg⁻¹ soils, but decreased Cd concentrations of the plants in 100 mg Cd kg⁻¹ soil. Overall, inoculation with Gv greatly improved the total Cd uptakes in all plant tissues at all Cd levels. The present results indicated that S. nigrum associated with Gv effectively improved the Cd uptake by plant and would be a new strategy in microbe-assisted phytoremediation for Cd-contaminated soils.     

Wood anatomical changes due to uptake of cadmium and lead from contaminated soils in Acer velutinum seedlings

We investigated wood anatomical changes due to uptake and accumulation of cadmium and lead from contaminated soils in Acer velutinum Boiss seedlings. Two-year old seedlings were exposed for 180 days to soil concentrations with varying cadmium and lead concentrations. We measured three wood anatomical traits, average vessel area(μm2), vessel number per square millimetre, and vessel lumen area percentage (%). For assessing the cadmium and lead accumulation, we measured the concentrations in the soil, leaf, stem, and root. Average vessel area and vessel lumen area percentage were similar (p>0.05) incontrol and treated seedlings. Vessel number per square millimetre showed a decreasing trend from pith to bark in control and treated seedlings, and the trend was more pronounced in treated seedlings. We conclude that vessel number per square millimetre in A. velutinum is influenced by soil contamination. A. velutinum Boiss is not a suitable species for remediation of soils contaminated by cadmium and lead but it can beused as an indicator of the soil lead contamination, because lead concentrations in seedlings increased with increasing amount of lead in the soil.     

Effect of Nitrogen Fertilizers on Zinc Accumulation in Fescue

Abstract

This research evaluated effects of nitrogen fertilizers on availability of zinc (Zn) in soils. Two slit loams of the Hadley series (Typic Udifluvents) were used. Zinc sulfate was mixed with the soils to give Zn at 125, 250, 500, or 1,000 mg/kg and incubated for 14 days. Fertilizers (compost, cow manure, urea) were mixed with the soils to supply N at 200 mg/kg. Fourteen days after the fertilizers were mixed with the Zn‐treated soils, soil samples were taken for analysis of plant‐available Zn by extraction with Morgan's solution or water. After the soil samples were taken, fescue (Festuca arundinacea Schreb.) seeds were placed into pots to assess germination, growth, and Zn accumulation. Higher concentrations of Morgan's extractable Zn were detected in soils treated with compost (201 mg/kg) than with calcium nitrate (179 mg/kg), manure (153 mg/kg), or urea (152 mg/kg). However, with water extraction, higher Zn concentrations were detected in soils treated with calcium nitrate (36 mg/kg) with the lowest concentrations being extracted from soils treated with urea (8 mg/kg). Extraction of Zn by Morgan's solution or water increased as the soil‐Zn levels increased. Fescue germinated and grew at all of the soil‐Zn levels. The highest concentration of Zn occurred in plants grown in soils amended with calcium nitrate or urea, and the lowest concentration was in plants grown in soils amended with compost or manure. Fescue grown in soils amended with urea had the largest dry mass, and plants grown with compost or manure had the smallest. Zinc concentration and accumulation for fescue shoots increased as the soil‐Zn levels increased. These results suggest that accumulation of Zn in fescue can be enhanced by selection of nitrogen‐containing fertilizers that affect the solubility of Zn in soils.