生物炭对植物生长发育及镉吸收的影响

发布时间：2018-10-12 13:16

【摘要】：近年来，随着城市化和工农业的快速发展，土壤、水体和大气的重金属污染日益加剧。我国一些粮食、蔬菜及药用植物种植区正遭受重金属污染的巨大威胁，镉污染问题尤为严重，镉超标事件时有发生，直接危害人体健康。食用药用植物与人类生活及健康关系十分密切，因此，研究蔬菜、药用植物在重金属污染环境中的安全生产及污染治理具有重要的科学价值和现实意义。生物炭(Biochar)具有众多优良特性，以往研究表明生物炭可影响土壤中重金属的形态和迁移行为，在土壤改良和污染修复上优势显著，但在生产上能多大程度上降低重金属污染、应用潜力及如何应用，，目前还不够清晰。为评价生物炭对蔬菜、药用植物的生长和减轻重金属污染的作用，分析生物炭的最佳使用量，本研究分别选用根菜类萝卜(Raphanus sativus L.)和叶菜类小青菜(Brassicachinensis L.)、水生多用途植物荷花'太空莲36'(Nelumbo nucifera 'Taikong Lian36')和陆生药用植物丹参(Salvia miltiorrhiza Bunge)为材料，添加五个炭土重量比的不同粒径生物炭到人工镉污染的土壤中进行盆栽实验，主要结果如下： (1)添加生物炭可明显促进圆萝卜和小青菜、荷花和丹参的生长发育，其叶片长势明显优于对照，株高和鲜重都有显著增加(P 0.05)，有效地减少了镉造成的胁迫伤害。生物炭对植物根冠比的影响明显且存在一定规律：添加生物炭更有利于促进圆萝卜根的膨大和小青菜叶的生长；显著增加荷花地下部的生长和莲藕膨大。这说明土壤添加生物炭在一定程度上提高了植物主要食用部分的产量。植物生长不受生物炭的粒径大小影响，但同添加比例存在显著联系。 (2)添加镉使4种植物产生明显的生理胁迫，但是添加生物炭的不同比例对镉胁迫的缓解作用不显著。尤其是荷花和丹参，可能由于添加的镉浓度不足以产生严重胁迫，两种植物对镉都表现出一定的耐受力。生物炭的比例梯度及粒径对实验植物的生理影响无明显规律。 (3)添加生物炭可使镉污染土壤中生长的圆萝卜地下部分、小青菜地上部分的镉含量分别减少81.21%、83.04%，使荷藕、荷梗、荷叶镉含量分别减少68.51%、81.41%、54.66%，丹参根和叶的镉含量分别减少43.63%、52.81%；降低4种植物体内镉的富集系数；除荷花外，生物炭可抑制另外3种植物体内的镉由地下部分向地上部分转运，从而减少镉在植物可食用部分的富集。 (4)土壤添加4mg/kg镉离子时，两种蔬菜的最佳加炭量均为10%；添加3mg/kg镉离子时，两种药用植物的最佳加炭量均为20%。此两比例的生物炭不仅能明显促进相应植物的生长，缓解重金属产生的生理胁迫，还可显著降低植物体内的重金属含量，使植物达到可食用标准，为生物炭作为一种基质治理重金属污染和提高食用药用植物生产的安全性提供科学的理论依据和实践参考。
[Abstract]:In recent years, with the rapid development of urbanization and industry and agriculture, the pollution of heavy metals in soil, water and atmosphere is becoming more and more serious. Some grain, vegetable and medicinal plant planting areas in China are under the threat of heavy metal pollution, especially cadmium pollution, which occurs from time to time and directly endangers human health. The relationship between edible medicinal plants and human life and health is very close. Therefore, it is of great scientific value and practical significance to study the safe production and pollution control of vegetables and medicinal plants in heavy metal polluted environment. Biochar (Biochar) has many excellent properties. Previous studies have shown that biochar can affect the morphology and migration behavior of heavy metals in soil, and has significant advantages in soil improvement and pollution remediation, but in production, the degree of heavy metal pollution can be reduced. Application potential and how to apply, at present is not clear enough. In order to evaluate the effect of biochar on the growth of vegetables and medicinal plants and to reduce the pollution of heavy metals, the optimum amount of biochar was analyzed. The root vegetables radish (Raphanus sativus L.) was selected in this study. The pot experiment was carried out in the soil polluted by cadmium by adding different sizes of biochar with five carbon to soil weight ratios, including lotus (36'(Nelumbo nucifera 'Taikong Lian36') and red miltiorrhiza (Salvia miltiorrhiza Bunge), a small leafy greengrocery (Brassicachinensis L.),) aquatic multi-purpose plant, and the terrestrial medicinal plant, Danshen (Salvia miltiorrhiza Bunge), as materials. The main results were as follows: (1) adding biochar could promote the growth and development of turnip, lotus and salvia miltiorrhiza, and its leaf growth was better than that of control. The plant height and fresh weight increased significantly (P 0.05), which effectively reduced the stress injury caused by cadmium. The effects of biochar on the ratio of root to shoot of plants were obvious and regular: adding biochar was more beneficial to promote the expansion of turnip root and the growth of leaves of small green vegetables, and significantly increased the growth of underground part of lotus flower and the expansion of lotus root. This indicated that the addition of biochar to soil increased the yield of the main edible parts of plants to some extent. Plant growth was not affected by the size of biochar, but there was a significant relationship with the addition ratio. (2) the addition of cadmium resulted in significant physiological stress in four species of plants. However, the effect of different proportion of biochar on the mitigation of cadmium stress was not significant. Especially for lotus and salvia miltiorrhiza, both plants showed some tolerance to cadmium because the concentration of cadmium was not enough to produce severe stress. The ratio gradient and particle size of biochar had no obvious effect on the physiology of experimental plants. (3) addition of biochar could reduce the cadmium content in the underground part of radish grown in cadmium polluted soil, and the cadmium content in aboveground part of small green vegetable decreased by 81.21% and 83.04, respectively. The cadmium contents in the roots and leaves of Salvia miltiorrhiza decreased 43.63% and 52.81%, respectively, and the cadmium enrichment coefficients in the four plants were decreased respectively. Except for lotus flowers, biochar could inhibit the transport of cadmium from the underground part to the aboveground part of the other three plants, with the exception of lotus flower, the content of cadmium in the roots and leaves of Salvia miltiorrhiza was decreased by 43.63% and 52.81%, respectively. Therefore, the enrichment of cadmium in edible parts of plants was reduced. (4) when 4mg/kg cadmium ion was added to the soil, the optimum carbon addition of both vegetables was 10%, and the optimum carbon addition amount of the two medicinal plants was 20% when 3mg/kg cadmium ion was added. These two ratios of biochar can not only significantly promote the growth of the corresponding plants, alleviate the physiological stress caused by heavy metals, but also significantly reduce the content of heavy metals in plants, so that the plants can reach the edible standard. It provides scientific theoretical basis and practical reference for biochar as a substrate to control heavy metal pollution and improve the safety of edible medicinal plants.
【学位授予单位】：湖南科技大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：X173

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