【作者】 肖艳平；

【导师】 陈玉成； 尹睿；

【作者基本信息】 西南大学 ， 微生物学， 2010， 硕士

【摘要】 砷是一种在自然界中分布极为广泛、毒性很强的类金属。土壤砷污染不仅影响农作物生长,还对人体健康和生态安全存在着极大威胁。目前,由于人为大量开采、生产和使用含砷化合物,使得砷污染现象越来越严重。因此,砷污染的治理技术已成为环境科学领域关注的焦点之一。然而,由于土壤砷污染存在量大面广的特点,应用传统的污染土壤修复技术存在技术难度较大、成本较高等问题。近年来发展起来的植物修复技术,掀起了砷污染土壤植物修复的研究热潮。本试验研究超富集砷的植物蜈蚣草的栽培技术以及对低砷污染土壤的修复,同时研究强化措施对普通植物玉米修复砷污染土壤的影响。研究的主要结果如下：通过温室盆栽试验,研究不同的处理对蜈蚣草孢子繁殖速度的影响。结果表明,化学处理使孢子萌发速度加快,缩短了孢子萌发时间,原叶体阶段喷施改良的Hogland营养液,可以加快蜈蚣草原叶体阶段的生长。同时研究施肥和接种AM真菌对蜈蚣草生长和富集砷的影响。结果表明,前期蜈蚣草生长对肥料的需求低,接种AM真菌的处理蜈蚣草生物量显著高于对照,AM真菌对蜈蚣草生长的促进作用在120d时显现出来。180d后,接种AM真菌显著提高蜈蚣草的生物量,并且适当添加N、P、K、Ca肥也促进蜈蚣草幼苗生长。接种AM真菌、添加钙和木质素干粉的处理蜈蚣草砷含量显著高于其它处理,可见,接种AM真菌、添加钙和木质素干粉能促进蜈蚣草对砷的富集。单接AM真菌、AM真菌与木质素干粉、AM真菌与钙能显著提高土壤pH值,施加氮、磷、钾肥土壤pH值较对照显著降低。另外,施加NPK肥的处理菌根侵染率显著低于其他处理,施肥对AM真菌侵染植物有很大的影响。单接AM真菌、AM真菌与木质素干粉、AM真菌与钙处理土壤脱氢酶活性显著高于其他处理,这可能与施肥使土壤pH降低有关。种植蜈蚣草60d后,单接AM真菌的处理土壤磷酸酶活性显著高于其它处理,接种AM真菌与木质素干粉的处理土壤磷酸酶活性显著高于施用N、P、K与AM真菌的处理,同时施加NPK肥和接种AM真菌在土壤磷酸酶活性中表现出拮抗效应。从总体来看,种植蜈蚣草180d后,土壤磷酸酶活性有所提高。春季,蜈蚣草幼苗长到10cm左右时,移栽到大田,结合蜈蚣草的生长特性,在夏秋炎热季节,用遮阳网遮荫。蜈蚣草对土壤和空气湿度要求较高,因此夏季要增加浇水,并结合叶面喷水,提高土壤和空气湿度,使生长茂盛。秋季则应减少浇水,保持土壤湿润为宜。蜈蚣草对低温的敏感性较强,而试验区冬季较冷,因此大田种植应覆盖薄膜保温,使蜈蚣草顺利度过冬天。春季在嫩叶长出前减去枯死衰老的叶片,有利于促进蜈蚣草的发芽。按照以上的管理措施,蜈蚣草生长茂盛,地上部干重达到32.33g/株,根系56.79g/株,合计总干重达到89.12g/株,产量达到6t/hm~2。可见,依据蜈蚣草的喜好而选择的管理措施,使蜈蚣草生长茂盛,为试验区内利用蜈蚣草修复As污染土壤提供了技术储备。另外,在砷污染农田土壤中,研究丛枝菌根、蚯蚓对玉米生长、土壤As形态变化以及土壤中酶活性变化的影响,尤其是对砷污染土壤修复效率的影响。结果发现,接种AM真菌和蚯蚓均显著提高玉米根系的AM真菌侵染率,且双接种处理显著高于单接种处理；接入蚯蚓或蚯蚓与AM真菌双接种显著提高玉米地上部、地下部生物量,并促进土壤中晶态的水合Fe、Al氧化物态砷含量显著升高；AM真菌与蚯蚓双接种土壤磷酸酶活性显著高于对照。接种AM真菌和蚯蚓均显著提高砷修复效率,且蚯蚓与AM真菌双接种显著高于单接种处理。经3年玉米修复后,只种植玉米的对照处理土壤中砷含量下降到19.70mg/kg,显著低于种植前,对砷的修复效率达到36.9%。接入蚯蚓和接种AM真菌的处理土壤中砷含量均显著低于对照,对砷的修复效率分别达到50.0%和55.4%。蚯蚓与AM真菌双接种处理土壤中砷含量显著低于单接AM真菌和蚯蚓的处理,该处理土壤中砷含量最低,比修复前降低了21.10mg/kg,对砷的修复效率达到676%,比对照提高了30.8%。接种AM真菌和蚯蚓可以促进玉米对砷污染土壤的修复。更多还原

【Abstract】 Arsenic is a kind of metal which is widely distributed in nature and high toxic. Soil arsenic contamination not only affects on crop, but also serious threat human health and ecological safety.At present, the situation of soil arsenic contamination is more and more serious due to the excessive exploiting, producing and use of arsenical compround. As a result, arsenic pollution has become the focus of environmental science. However, traditional remediations of contaminated soil are difficult and costly due to the characters of arsenic contamination of soil was huge in quantity and wide in spread, In recent years, phytoremediation of heavy metal contaminated soil, has become a hot spot of arsenic contaminated soil remediation. An experiment was conducted to investigate the cultivation techniques of Pteris vittata L. and affect to remediation of the low arsenic contaminated soils. Study to strengthen measures on the general plant at the same time, corn is a good candidate for phytoremediation of arsenic-contaminated soils. The main results are as follows:Through pot experiment in greenhouse, we have studied the impacts on Pteris vittata L spores reproduction speed by different treatments. The results show that the chemical treatment can accelerated germination speed, reduced germination time. The growth of Pteris vittata L prothallus stage is accelerated after spraying improved Hogland nutrient solution, which speed up the prothallus of Pteris vittata L on the growth.The research on the effects of inoculation of arbuscular mycorrhizal fungus (AM) and fertilizztion on the growth and the capability of As enrichment of Pteris vittata L is carried out at the same time. The results showed that the need of fertilizer is low during prophase of Pteris vittata L and Pteris vittata L inoculation with AM has significantly higher biomass than control, and the promoting effect on Pteris vittata L by arbuscular mycorrhizal fungus (AM) could be seen after 120 days.The experiment data showed that inoculation with AM can significantly enhance the biomass of Pteris vittata L and adding proper content of N、P、K、Ca fertilizer can also promote the growth of Pteris vittata L seedling. It was also found that compared with other treatments, inoculation with AM and adding Ca and organic could significantly enhance the content of As in Pteris vittata L. We can conciude that inoculation with AM and adding Ca and organic can promote the enrichment of As in Pteris vittata L.The treatments of inoculation of AM, inoculation of AM and adding organic, inoculation of AM and adding Ca can all increase pH of soil significantly while the pH of soil adding NPK fertilizers were lower than the control significantly. In addition, mycorrhizal infection rate of treatments which adding NPK fertilizers also were lower than other treatments significantly,we can conclude that fertilization has strong impact on AM infection rate. The treatments of inoculation of AM, inoculation of AM and adding organic, inoculation of AM and adding Ca have higher soil dehydrogenase activity than other treatments remarkably, which may be related to the decreasing pH by fertilizer.After planting Pteris vittata L for 60 days, the treatments of inoculation of AM has higher soil phosphatase activity than other treatments remarkably. The treatments of inoculation of AM and adding organic has obviously higher soil phosphatase activity than inoculation of AM and adding NPK fertilizer which has antagonistic effect in soil phosphatase activity.Overall, soil phosphatase activity has been improved after planting for 180 days.In spring, when the seedlings of Pteris vittata L grow about 10 cm, we transplant them in the field. According to the growth characteristics of Pteris vittata L, shading net should be used in hot summer. Pteris vittata L has strict requirement of soil and atmosphere humidity and more watering and spraying is necessary during summer.While in autumn it would be better have less watering to keep soil wetness. Pteris vittata L is sensitive to the low temperature, so it should be coverd with thin film in field for heat preservation take the cold winter of Jiangsu province into consideration. Cutting out withered and aged leaves before tender leaves come out in spring would promote the budding of Pteris vittata L.Through above management measures, the Pteris vittata L grow flourish. The per shoot dry weight is 32.33 gram. The per weight of root is 56.79 gram, and total dry weight is 89.12 gram, the yield of a unit area is 6 ton/hm~2. The management measures, according to the preference of Pteris vittata L, made Pteris vittata L grow well, which offer technical reserves for the remediation of As-contaminated soil by Pteris vittata L in Jiangsu Province.In addition, a field experiment was conducted to investigate the effects of inoculation of arbuscular mycorrhizal fungus (AM) or/and earthworms on phytoremediation efficiency of the low-arsenic contaminated soil by maize. The results showed that inoculation with AM or earthworms alone could significantly increase mycorrhizal infection of maize roots. And inoculation of AM and earthworms in combination showed the mycorrhizal infection was much higher than inoculation of AM or earthworms alone; While inoculating earthworms alone or combination with AM fungi, they could increase biomass of maize shoot and root,and also could significantly enhance the content of As involved in well-crystallized orhydrous oxides of ferrum and aluminum. It was also found that compared with the control treatment, the phosphatase activity in soils of AM fungi in combination with earthworms were significantly increased.Inoculation with AM fungi or earthworms alone could greatly enhance the phytoremediation efficiency of As-contaminated soil, but inoculation of earthworms and AM fungi in combination showed the highest remediation efficiency. After 3 years, the content of soil arsenic decrease to 19.70 mg/kg in the control, which is significantly lower than pre-implantation,the efficiency of arsenic is 36.9%. The content of soil arsenic inoculation with AM or earthworms alone could significantly lower than the control, the efficiency is 50.0% and 55.4% respectively. The content of soil arsenic, which inoculation of earthworms and AM fungi in combination is the lowest, is significantly lower than inoculation with AM or earthworms alone. The efficiency is 67.6%by inoculation of earthworms and AM fungi in combination, increase about 30.8% compared with the control. Inoculation of AM and earthworms could promote the phytoremediation efficiency of As-contaminated soil when maize was planted.更多还原